TOSCA Version 2.0
Committee Specification Draft 05
19 January 2023
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Technical Committee:
OASIS Topology and Orchestration Specification for Cloud Applications (TOSCA) TC
Chair:
Chris Lauwers (lauwers@ubicity.com), Individual Member
Editors:
Chris Lauwers (lauwers@ubicity.com), Individual Member
Calin Curescu (calin.curescu@ericsson.com), Ericsson
This specification replaces or supersedes:
This specification is related to:
Declared XML namespace:
Abstract:
The OASIS TOSCA TC works to enhance the portability of cloud applications and services across their entire lifecycle. TOSCA will enable the interoperable description of application and infrastructure cloud services, the relationships between parts of the service, and the operational behavior of these services (e.g., deploy, patch, shutdown) independent of the supplier creating the service or of any particular cloud provider or hosting technology. TOSCA will also make it possible for higher-level operational behavior to be associated with cloud infrastructure management.
By increasing service and application portability in a vendor-neutral ecosystem, TOSCA will enable:
Status:
This document was last revised or approved by the OASIS Topology and Orchestration Specification for Cloud Applications (TOSCA) TC on the above date. The level of approval is also listed above. Check the “Latest stage” location noted above for possible later revisions of this document. Any other numbered Versions and other technical work produced by the Technical Committee (TC) are listed at https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=tosca#technical.
TC members should send comments on this specification to the TC’s email list. Others should send comments to the TC’s public comment list, after subscribing to it by following the instructions at the “Send A Comment” button on the TC’s web page at https://www.oasis-open.org/committees/tosca/.
This specification is provided under the RF on Limited Terms Mode of the OASIS IPR Policy, the mode chosen when the Technical Committee was established. For information on whether any patents have been disclosed that may be essential to implementing this specification, and any offers of patent licensing terms, please refer to the Intellectual Property Rights section of the TC’s web page (https://www.oasis-open.org/committees/tosca/ipr.php).
Note that any machine-readable content (Computer Language Definitions) declared Normative for this Work Product is provided in separate plain text files. In the event of a discrepancy between any such plain text file and display content in the Work Product's prose narrative document(s), the content in the separate plain text file prevails.
Citation format:
When referencing this specification, the following citation format should be used:
[TOSCA-v2.0]
TOSCA Version 2.0. Edited by Chris Lauwers and Calin Curescu. 19 January 2023. OASIS Committee Specification Draft 05. https://docs.oasis-open.org/tosca/TOSCA/v2.0/csd05/TOSCA-v2.0-csd05.html. Latest stage: https://docs.oasis-open.org/tosca/TOSCA/v2.0/TOSCA-v2.0.html.
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Table of Contents
3.1 Service Templates, Node Templates, and Relationships
3.2 Interfaces, Operations, and Artifacts
3.4 Requirements and Capabilities
3.5 Decomposition of Service Templates
3.7 Archive Format for Cloud Applications
4.1.2.1 Creating Service Representations
4.1.2.2 Requirement Fulfillment
5.1.1 Modeling concepts and goals
5.1.2 Modeling definitions and reuse
5.1.3 Goal of the derivation and refinement rules
5.2.1.3 Top-level keyname definitions
5.2.1.3.1 tosca_definitions_version
5.2.3.1.2.1 Single-line grammar:
5.2.3.1.2.2 Multi-line grammar
5.2.3.1.3 Import processing rules
5.2.3.1.3.1 Importing profiles
5.2.3.1.3.2 Importing service templates
5.2.3.2.1 Additional Requirements
5.2.3.3.2.1 Single-line grammar:
5.2.3.3.2.2 Multi-line grammar
5.2.4 Additional information definitions
5.2.4.1 Description definition
5.2.5.1 General derivation and refinement rules
5.2.5.2 Common keynames in type definitions
5.2.6 Service template definition
5.2.6.2.3 relationship_templates
5.2.6.2.7 substitution_mapping
5.2.6.2.7.1 requirement_mapping
5.3.1.4 Additional Requirements
5.3.2.3 Additional requirements
5.3.4.3 Additional requirements
5.3.5 Capabilities and Requirements
5.3.5.2.4.1 Simple notation example
5.3.5.2.4.2 Full notation example
5.3.5.2.5 Additional requirements
5.3.5.5 Requirement definition
5.3.5.5.1.1 Additional keynames for multi-line relationship grammar
5.3.5.5.2.1 Simple grammar (Capability Type only)
5.3.5.5.2.2 Extended grammar (with Node and Relationship Types)
5.3.5.5.2.3 Extended grammar for declaring Parameter Definitions on the relationship’s Interfaces
5.3.5.5.4 Additional requirements
5.3.5.5.6 Requirement definition is a tuple with a filter
5.3.5.6 Requirement assignment
5.3.5.6.2.2 Extended notation:
5.3.5.6.2.4 Extended grammar with capacity allocation
5.3.5.6.4.1 Example 1 – Hosting requirement on a Node Type
5.3.5.6.4.2 Example 2 - Requirement with Node Template and a custom Relationship Type
5.3.5.6.4.3 Example 3 - Requirement for a Compute node with additional selection criteria (filter)
5.3.5.6.4.4 Example 4 - Requirement assignment for definition with count_range: [2,2]
5.3.5.6.4.5 Example 5 - Requirement assignment for definition with capacity allocation
5.3.5.7 Node Filter definition
5.3.6.1.5 Additional Requirements
5.3.6.4.4 Additional requirements
5.3.6.4.5.1 Single-line example
5.3.6.4.5.2 Multi-line example with shorthand implementation definitions
5.3.6.4.5.3 Multi-line example with extended implementation definitions
5.3.6.5.3 Additional requirements
5.3.6.6 Notification definition
5.3.6.6.4 Additional requirements
5.3.6.7 Notification assignment
5.3.6.7.3 Additional requirements
5.3.6.8 Operation and notification implementation definition
5.3.6.8.2.1 Short notation for use with single artifact
5.3.6.8.2.2 Short notation for use with multiple artifacts
5.3.6.8.2.3 Extended notation for use with single artifact
5.3.6.8.2.4 Extended notation for use with multiple artifacts
5.3.7.1.5 Additional Requirements
5.3.7.2.2.2 Extended notation:
5.4 Properties, Attributes, and Parameters
5.4.2.1.5 Additional Requirements
5.4.2.4 TOSCA scalar-unit type
5.4.2.4.2 Additional requirements
5.4.2.4.6 scalar-unit.frequency
5.4.3.1.1.1 Square bracket notation
5.4.3.1.1.2 Bulleted list notation
5.4.3.1.2 Declaration Examples
5.4.3.1.2.1 List declaration using a simple type
5.4.3.1.2.2 List declaration using a complex type
5.4.3.1.3.1 Square bracket notation
5.4.3.1.3.2 Bulleted list notation
5.4.3.2.1.1 Single-line grammar
5.4.3.2.1.2 Multi-line grammar
5.4.3.2.2 Declaration Examples
5.4.3.2.2.1 Map declaration using a simple type
5.4.3.2.2.2 Map declaration using a complex type
5.4.3.2.3.1 Single-line notation
5.4.3.2.3.2 Multi-line notation
5.4.4.4 Additional Requirements
5.4.4.5.1 Defining a complex datatype
5.4.4.5.2 Defining a datatype derived from an existing datatype
5.4.6 Validation clause definition
5.4.7.1 Attribute and Property reflection
5.4.7.6 Additional Requirements
5.4.8.3 Additional Requirements
5.4.9.1 Attribute and Property reflection
5.4.9.5 Additional Requirements
5.4.10.3 Additional requirements
5.4.11.4 Additional requirements
5.4.12 Parameter value assignment
5.4.12.3 Additional requirements
5.4.13 Parameter mapping assignment
5.4.13.3 Attribute selection format
5.4.13.4 Additional requirements
5.4.15.4.1 Square root function with several signatures
5.4.15.4.2 Function with list of arguments
5.4.15.4.3 Function with no arguments
5.4.15.4.4 Function with polymorphic arguments/result inside of lists
5.4.15.4.5 Defining a list in a map argument
5.4.15.4.6 User-defined function usage
5.5.1.4 Additional requirements
5.5.2.4 Additional constraints
5.6.6.1 Delegate workflow activity definition
5.6.6.2 Set state activity definition
5.6.6.3 Call operation activity definition
5.6.6.4 Inline workflow activity definition
5.7.1 Imperative Workflow definition
5.7.2 Workflow precondition definition
5.7.3 Workflow step definition
6.1 Representation graph query functions
6.1.2.2.1 The simplified TOSCA_PATH definition in BNF format
6.1.4.3.1 Example: Retrieving artifact without specified location
6.1.4.3.2 Example: Retrieving artifact as a local path
6.1.4.3.3 Example: Retrieving artifact in a specified location
6.2.3 Boolean list, map and string functions
6.3 String, list, and map functions
7 TOSCA Cloud Service Archive (CSAR) format
7.1 Overall Structure of a CSAR
7.2.1 Custom keynames in the TOSCA.meta file
7.3 Archive without TOSCA-Metadata
9.2 Conformance Clause 1: TOSCA YAML service template
9.3 Conformance Clause 2: TOSCA processor
9.4 Conformance Clause 3: TOSCA orchestrator
9.5 Conformance Clause 4: TOSCA generator
9.6 Conformance Clause 5: TOSCA archive
[All text is normative unless otherwise labeled]
This specification is provided under the RF on Limited Terms Mode of the OASIS IPR Policy, the mode chosen when the Technical Committee was established. For information on whether any patents have been disclosed that may be essential to implementing this specification, and any offers of patent licensing terms, please refer to the Intellectual Property Rights section of the TC’s web page (https://www.oasis-open.org/committees/tosca/ipr.php).
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] and [RFC8174] when, and only when, they appear in all capitals, as shown here.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <http://www.rfc-editor.org/info/rfc8174>.
[YAML-1.2] YAML, Version 1.2, 3rd Edition, Patched at 2009-10-01, Oren Ben-Kiki, Clark Evans, Ingy döt Net http://www.yaml.org/spec/1.2/spec.html
[YAML-TS-1.1] Timestamp Language-Independent Type for YAML Version 1.1, Working Draft 2005-01-18, http://yaml.org/type/timestamp.html
[ISO-IEC-21320-1] ISO/IEC 21320-1 "Document Container File — Part 1: Core", https://www.iso.org/standard/60101.html
[Apache] Apache Server, https://httpd.apache.org/
[Chef] Chef, https://wiki.opscode.com/display/chef/Home
[NodeJS] Node.js, https://nodejs.org/
[Puppet] Puppet, http://puppetlabs.com/
[WordPress] WordPress, https://wordpress.org/
[Maven-Version] Apache Maven version policy draft: https://cwiki.apache.org/confluence/display/MAVEN/Version+number+policy
[JSON-Spec] The JSON Data Interchange Format (ECMA and IETF versions):
· http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf
· https://tools.ietf.org/html/rfc7158
[JSON-Schema] JSON Schema specification:
· http://json-schema.org/documentation.html
[XMLSpec] XML Specification, W3C Recommendation, February 1998, http://www.w3.org/TR/1998/REC-xml-19980210
[XML Schema Part 1] XML Schema Part 1: Structures, W3C Recommendation, October 2004, http://www.w3.org/TR/xmlschema-1/
[XML Schema Part 2] XML Schema Part 2: Datatypes, W3C Recommendation, October 2004, http://www.w3.org/TR/xmlschema-2/
[IANA register for Hash Function Textual Names] https://www.iana.org/assignments/hash-function-text-names/hash-function-text-names.xhtml
[Jinja2] Jinja2, jinja.pocoo.org/
[Twig] Twig, https://twig.symfony.com
Cloud computing can become more valuable if the creation and lifecycle management of application, infrastructure, and network services can be fully automated and supported across a variety of deployment environments. The core TOSCA specification provides a language for describing service components and their relationships using a service topology, and it provides for specifying the lifecycle management procedures that allow for creation or modification of services using orchestration processes. The combination of topology and orchestration in a Service Template describes what is needed in different environments to enable automated deployment of services and their management throughout the complete service lifecycle (e.g. scaling, patching, monitoring, etc.).
TOSCA is a domain-specific language for designing services and for defining the deployment and run-time management aspects of these services with the goal of enabling fully automated service management. As such, TOSCA is designed to support all three phases of the service lifecycle:
1. Day 0—Service Design: Service designers use TOSCA to model services as topology graphs that consist of nodes and relationships. Nodes model the components of which a service is composed, and relationships model dependencies between these service components.
2. Day 1—Service Deployment: TOSCA can also be used to define mechanisms for deploying TOSCA service topologies on external platforms.
3. Day 2—Service Management: TOSCA can enable run-time management of services by providing support for updating and/or upgrading deployed services and by providing service assurance functionality.
Note that it is not mandatory for compliant TOSCA implementations to support all three service lifecycle phases. Some implementations may use TOSCA only for service design and delegate orchestration and ongoing lifecycle management functionality to external (non-TOSCA) orchestrators. Other implementations may decide to use TOSCA for all three phases of the service lifecycle.
TOSCA can be used to specify automated lifecycle management of the following:
· Infrastructure-as-a-Service Clouds: automate the deployment and management of workloads in IaaS clouds such as OpenStack, Amazon Web Services, Microsoft Azure, and others.
· Cloud-native applications: deploy containerized applications and micro-services, for example by interfacing to orchestration platforms such as Kubernetes.
· Network Functions Virtualization: define the management of Virtual Network Functions and their composition into complex network services.
· Software Defined Networking: support on-demand creation of network services (for example SD-WAN).
· Functions-as-a-Service: define abstract software applications without any deployment or operational considerations.
· IoT and Edge computing: deploy services at the network edge with the goal of minimizing latency.
· Process automation: support open and interoperable process control architectures.
This list is by no means intended to be exhaustive and only serves to demonstrate the breadth of application domains that can benefit from TOSCA’s automated lifecycle management capabilities.
Different kinds of processors and artifacts qualify as implementations of TOSCA. Those that this specification is explicitly mentioning or referring to fall into the following categories:
· TOSCA processor (or “processor”): An engine or tool that is capable of parsing and interpreting a TOSCA service template for a particular purpose. For example, the purpose could be validation, translation or visual rendering.
· TOSCA orchestrator (also called orchestration engine): A TOSCA processor that interprets a TOSCA file or a TOSCA CSAR in order to instantiate, deploy, and manage the described application in a Cloud.
· TOSCA translator: A tool that translates TOSCA files into documents that use another language, such as Kubernetes Helm charts or Amazon CloudFormation templates.
· TOSCA template generator: A tool that generates a TOSCA file. An example of generator is a modeling tool capable of generating or editing a TOSCA file (often such a tool would also be a TOSCA processor).
The above list is not exclusive. The above definitions should be understood as referring to and implementing TOSCA as described in this document.
The following terms are used throughout this specification and have the following definitions when used in context of this document.
Term |
Definition |
Instance Model |
A deployed service is a running instance of a Service Template. The instance is typically derived by running a declarative workflow that is automatically generated based on the node templates and relationship templates defined in the service template. |
Node Template |
A Node Template specifies the occurrence of a component node as part of a service template. Each Node Template refers to a Node Type that defines the semantics of the node (e.g., properties, attributes, requirements, capabilities, interfaces). Node Types are defined separately for reuse purposes. |
Relationship Template |
A Relationship Template specifies the occurrence of a relationship between nodes in a service template. Each Relationship Template refers to a Relationship Type that defines the semantics relationship (e.g., properties, attributes, interfaces, etc.). Relationship Types are defined separately for reuse purposes. |
A Service Template is typically used to specify the “topology” (or structure) and “orchestration” (or invocation of management behavior) of IT services so that they can be provisioned and managed in accordance with constraints and policies. |
|
Topology Model |
A Topology Model defines the structure of a service in the context of a Service Template. A Topology model consists of a set of Node Template and Relationship Template definitions that together define the topology of a service as a (not necessarily connected) directed graph. |
Abstract Node Template |
An abstract node template is a node template that doesn’t define any implementations for the TOSCA lifecycle management operations. Service designers explicitly mark node templates as abstract using the substitute directive. TOSCA orchestrators provide implementations for abstract node templates by finding substituting templates for those node templates. |
The TOSCA language introduces a YAML-based grammar for creating service templates that define the lifecycle management of application, infrastructure, and network services. The language defines a metamodel for specifying both the structure of a service as well as its management aspects. Within a TOSCA file, a Service Template defines the structure of a service. Interfaces, Operations, and Workflows define how service elements can be created and terminated as well as how they can be managed during their whole lifetimes. Policies specify operational behavior of the service such as quality-of-service objectives, performance objectives, and security constraints, and allow for closed-loop automation. The major elements defining a service are depicted in Figure 1.
Within a TOSCA file, a Service Template defines the topology model of a service as a directed acyclic graph. Each node in this graph is represented by a Node Template. A Node Template specifies the presence of an entity of a specific Node Type as a component of a service. A Node Type defines the properties of such a component (via Node Type Properties) and the operations (via Interfaces) available to manipulate the component. Node Types are defined separately for reuse purposes. In a service template a Node Template assigns values to the properties defined in the Node Type.
Figure 1: Structural Elements of a Service Template and their Relations
For example, consider a service that consists of an application server, a process engine, and a process model. A Service Template defining that service would include one Node Template of Node Type “application server”, another Node Template of Node Type “process engine”, and a third Node Template of Node Type “process model”. The application server Node Type defines properties like the IP address of an instance of this type, an operation for installing the application server with the corresponding IP address, and an operation for shutting down an instance of this application server. A constraint in the Node Template can specify a range of IP addresses available when making a concrete application server available.
Node templates may include one or more relationships to other node templates in the Service Template. Relationships represent the edges in the service topology graph. The node template that includes the relationship definition is implicitly defined as the source node of the relationship and the target node is explicitly specified as part of the relationship definition. Each relationship definition refers to a Relationship Type that defines the semantics and any properties of the relationship. Relationship Types are defined separately for reuse purposes.
In the example above, a relationship can be established from the process engine Node Template to the application server Node Template with the meaning “hosted by”, and from the process model Node Template to the process engine Node Template with meaning “deployed on”.
Both node and relationship types may define lifecycle operations that implement the behavior an orchestration engine can invoke when instantiating a service template. For example, a node type for some software product might provide a ‘create’ operation to handle the creation of an instance of a component at runtime, or a ‘start’ or ‘stop’ operation to handle a start or stop event triggered by an orchestration engine.
Operations that are related to the same management mission (e.g. lifecycle management) are grouped together in Interfaces that are defined by node and relationship types. Just like other TOSCA entities, interfaces refer to their corresponding Interface Type that defines the group of operations that are part of the interface. Interface Types can also define notifications that represent external events that are generated by the outside world and received by the orchestrator.
The implementations of interface operations can be provided as TOSCA artifacts. An artifact represents the content needed to provide an implementation for an interface operation. A TOSCA artifact could be an executable (e.g. a script, an executable program, an image), a configuration file or data file, or something that might be needed so that another executable can run (e.g. a library). Artifacts can be of different types, for example EJBs or python scripts. The content of an artifact depends on its type. Typically, descriptive metadata (such as properties) will also be provided along with the artifact. This metadata might be needed to properly process the artifact, for example by describing the appropriate execution environment.
A deployed service is an instance of a service template. More precisely, the instance is created by instantiating the Service Template of its TOSCA file by running workflows that are most often automatically created by the orchestrator and that invoke the interface operations of the Node Types or the Node Templates. Orchestrators can automatically generate workflows by using the relationship between components to derive the order of component instantiation. For example, during the instantiation of a two-tier application that includes a web application that depends on a database, an orchestration engine would first invoke the ‘create’ operation on the database component to install and configure the database, and it would then invoke the ‘create’ operation of the web application to install and configure the application (which includes configuration of the database connection).
Interface operations invoked by workflows must use actual values for the various properties of the various Node Templates and Relationship Templates of the Service Template. These values can come from input passed in by users as triggered by human interactions with the orchestrator or the templates can specify default values for some properties. For example, the application server Node Template will be instantiated by installing an actual application server at a concrete IP address considering the specified range of IP addresses. Next, the process engine Node Template will be instantiated by installing a concrete process engine on that application server (as indicated by the “hosted by” relationship template). Finally, the process model Node Template will be instantiated by deploying the process model on that process engine (as indicated by the “deployed on” relationship template).
We discussed earlier how relationships are used to link node templates together into a service topology graph. However, it may not always be possible to define all node templates for a given service topology within a single service template. For example, modular design practices may dictate that different service subcomponents be modeled using separate service templates. This may result in relationships that need to be established across multiple service templates. Additionally, relationships may need to target components that already exist and do not need to be instantiated by an orchestrator. For example, relationships may reference physical resources that are managed in a resource inventory. Service templates may not include node templates for these resources.
TOSCA accommodates these scenarios using requirements and capabilities of node templates. A requirement expresses that one component depends on (requires) a feature provided by another component, or that a component has certain requirements against the hosting environment such as for the allocation of certain resources or the enablement of a specific mode of operation. Capabilities represent features exposed by components that can be used to fulfill requirements of other components.
Relationships are the result of fulfilling a requirement in one node template using a capability of a different node template. If both source and target node templates are defined in the same service template, service designers typically define the relationship between these node templates explicitly. Requirements that do not explicitly specify a target node must be fulfilled by the orchestrator at service deployment time. Orchestrators can take multiple service templates into account when fulfilling requirements, or they can attempt to use resources managed in an inventory, which will result in relationships that are established across service template boundaries.
Requirements and capabilities are modeled by annotating Node Types with Requirement Definitions and Capability Definitions. Capability Types are defined as reusable entities so that those definitions can be used in the context of several Node Types. Requirement definitions can specify the relationship type that will be used when creating the relationship that fulfills the requirement.
Figure 2: Requirements and Capabilities
Node Templates which have corresponding Node Types with Requirement Definitions or Capability Definitions will include representations of the respective Requirements and Capabilities with content specific to the respective Node Template.
Requirements can be matched in two ways as briefly indicated above: (1) requirements of a Node Template can be matched by capabilities of another Node Template in the same Service Template by connecting the respective requirement-capability-pairs via relationships; (2) requirements of a Node Template can be matched by the orchestrator, for example by allocating needed resources for a Node Template during instantiation.
TOSCA provides support for decomposing service components using the Substitution Mapping feature. For example, a Service Template for a business application that is hosted on an application server tier might focus on defining the structure and manageability behavior of the business application itself. The structure of the application server tier hosting the application can be provided in a separate Service Template built by another vendor specialized in deploying and managing application servers. This approach enables separation of concerns and re-use of common infrastructure templates.
Figure 3: Service Template Decomposition
From the point of view of a Service Template (e.g. the business application Service Template from the example above) that uses another Service Template, the other Service Template (e.g. the application server tier) “looks” like just a Node Template. During deployment, however, this Node Template can be substituted by the second Service Template if it exposes the same external façade (i.e. properties, capabilities, etc.) as the Node Template. Thus, a substitution with any Service Template that has the same facade as a certain Node Template in one Service Template becomes possible, allowing for a flexible composition of different Service Templates. This concept also allows for providing substitutable alternatives in the form of Service Templates. For example, a Service Template for a single node application server tier and a Service Template for a clustered application server tier might exist, and the appropriate option can be selected per deployment.
Non-functional behavior or quality-of-services are defined in TOSCA by means of policies. A Policy can express such diverse things like monitoring behavior, payment conditions, scalability, or continuous availability, for example.
A Node Template can be associated with a set of Policies collectively expressing the non-functional behavior or quality-of-services that each instance of the Node Template will expose. Each Policy specifies the actual properties of the non-functional behavior, like the concrete payment information (payment period, currency, amount etc.) about the individual instances of the Node Template.
These properties are defined by a Policy Type. Policy Types might be defined in hierarchies to properly reflect the structure of non-functional behavior or quality-of-services in particular domains. Furthermore, a Policy Type might be associated with a set of Node Types the non-functional behavior or quality-of-service it describes.
Policy Templates provide actual values of properties of the types defined by Policy Types. For example, a Policy Template for monthly payments for US customers will set the “payment period” property to “monthly” and the “currency” property to “US$”, leaving the “amount” property open. The “amount” property will be set when the corresponding Policy Template is used for a Policy within a Node Template. Thus, a Policy Template defines the invariant properties of a Policy, while the Policy sets the variant properties resulting from the actual usage of a Policy Template in a Node Template.
In order to support in a certain environment for the execution and management of the lifecycle of a cloud application, all corresponding artifacts have to be available in that environment. This means that beside the service template of the cloud application, the deployment artifacts and implementation artifacts have to be available in that environment. To ease the task of ensuring the availability of all of these, this specification defines a corresponding archive format called CSAR (Cloud Service ARchive).
A CSAR is a container file, i.e. it contains multiple files of possibly different file types. These files are typically organized in several subdirectories, each of which contains related files (and possibly other subdirectories etc.). The organization into subdirectories and their content is specific for a particular cloud application. CSARs are zip files, typically compressed. A CSAR may contain a file called TOSCA.meta that describes the organization of the CSAR.
When defining services using TOSCA, we must distinguish between four kinds of entities:
1. TOSCA Types: TOSCA types define re-usable building blocks that can be used during service design. For example, TOSCA Node Types define reusable service components, including their configurable properties.
2. TOSCA Templates: TOSCA templates define (typed) components of a service. For example, service templates include node templates that assign specific values (often using TOSCA intrinsic functions) to the configurable properties defined in the corresponding node types. It is not uncommon to have multiple node templates of the same node type in a service template.
3. Representations: At deployment time, TOSCA implementations combine TOSCA service templates with deployment-specific input values to create run-time representations of the service that is to be deployed and managed. Note that TOSCA does not standardize an object model for representations. Instead, such models are implementation specific.
4. External Implementations: These are the actual entities in the external world that correspond to the representations managed by the orchestrator. TOSCA implementations that provide runtime service management must keep their internal service representations in sync with the actual state of the external implementations.
This section presents a TOSCA Functional Architecture and an associated operational model that supports the three service lifecycle phases outline above. Note that this functional architecture is not intended to prescribe how TOSCA must be implemented. Instead, it aims to provide users of TOSCA with a mental model of how TOSCA implementations are expected to process TOSCA files.
While TOSCA does not mandate that compatible implementations must support all three lifecycle phases, a complete architecture must anticipate all three and must include support for all four kinds of TOSCA entities. The TOSCA architecture defined here illustrates how the various TOSCA entities are used and how they are related.
Figure 1: TOSCA Functional Architecture
The functional architecture defines the following three blocks:
1. TOSCA Processor: This functional block defines functionality that must be provided by all TOSCA implementations. TOSCA processors convert TOSCA-based service definitions into service representations that can be processed by an Orchestrator.
2. Orchestrator: This functional block creates external implementations on various resource platforms based on the service representations created by a TOSCA processor. The orchestration functionality can itself be defined using TOSCA or can be provided by external (non-TOSCA) orchestration platforms.
3. Platform: In the context of a TOSCA architecture, platforms represent external cloud, networking, or other infrastructure resources on top of which service entities can be created.
The remainder of this section describes each of these functional blocks in more detail.
At the core of a compliant TOSCA implementation is a TOSCA Processor that can create service representations from TOSCA service templates. A TOSCA Processor contains the following functional blocks:
· Accepts a single TOSCA file plus imported TOSCA files (files without a “service_template”)
· Can (optionally) import these units from one or more repositories, either individually or as complete profiles
· Outputs valid normalized node templates and unresolved requirements (one-to-one equivalency)
A resolver performs the following functions
· Applies service inputs.
· Converts normalized node templates to node representations (one-to-one equivalency [cardinality?]) [a full TOSCA orchestrator can manage these instead of the external orchestrator/platform]
· Calls intrinsic functions (on demand for all the above) using the graph of node representations.
· Satisfies all requirements and creates the relationship graph (an unsatisfied requirement results in an error)
An orchestrator performs the following actions:
· (Continuously) turns node representations into zero or more node implementations (one-to-any)
· (Continuously) updates node representation attribute values (error if they do not adhere to TOSCA type validation clauses or property definition validation clauses) [we still don’t know how to handle multiplicity]
· (Continuously) reactivates the resolver: outputs and even satisfaction of requirements may change.
· (Optionally) changes the node representations themselves for day 2 transformations.
Except for the examples, this section is normative and describes the YAML grammar, definitions, and semantics for all keynames that are defined in the TOSCA Version 2.0 specification.
This section defines the models and the modeling goals that comprise the TOSCA Version 2.0 specification.
TBD. Here we should have selected core concepts of TOSCA 1.0 from section “3 Core Concepts and Usage Pattern” and this section should be a more in-depth section than section 2.1 in this document.
Add a metamodel picture
Explain separation of concerns and different roles. Refer to email from Peter.
The TOSCA metamodel includes complex definitions used in types and templates. Reuse concepts simplify the design of TOSCA templates by allowing relevant TOSCA entities to use and/or modify definitions already specified during entity type design. The following four concepts are clarified next:
· Definition:
– The TOSCA specification is based on defining modeling entities.
– Entity definitions are based on different sets of keynames (with specific syntax and semantics) that are associated with values (of a specific format).
· Derivation:
– Specific TOSCA entities support a type definition.
– When defining a type, it can be derived from a parent type and inherit all the definitions of the parent type.
– The derivation rules describe what (keyname) definitions are inherited from the parent type and further if and how they can be expanded or modified. Note that some definitions (for example, “version”) and intrinsic to the type declaration and so are not inherited.
– A parent type can in turn be derived from a parent type. There is no limit to the depth of a chain of derivations.
· Refinement:
– Definitions within a type definition consist of the definition of keynames and other TOSCA entities (e.g. properties, requirements, capabilities, etc.). Definitions within a parent type can be refined (adjusted) to better suit the needs of the referencing type.
– The refinement rules pertaining to an entity describe how such entity definitions that are inherited from the parent type during a type derivation can be expanded or modified.
· Augmentation:
– Definitions within a parent type can be expanded, which is the addition of properties, to better suit the requirements of the referencing type.
– The augmentation rules pertaining to an entity describe how the inherited parent type during a type derivation can be added to.
· Assignment:
– When creating a service template, we specify several entities that are part of the template (e.g., nodes, relationships, groups, etc.).
– When adding such an entity in the service template, for some definitions that appear in the corresponding entity type (e.g., properties, operations, requirements, etc.) we may (or must) assign a certain specification (or value).
The main reason for derivation and refinement rules is to create a framework useful for a consistent TOSCA type profile creation. The intuitive idea is that a derived type follows to a large extent the structure and behavior of a parent type, otherwise it would be better to define a new "not derived" type.
The guideline regarding the derivation rules is that a node of a derived type should be usable instead of a node of the parent type during the selection and substitution mechanisms. These two mechanisms are used by TOSCA templates to connect to TOSCA nodes and services defined by other TOSCA templates:
· The selection mechanism allows a node instance created a-priori by another service template to be selected for usage (i.e., building relationships) to the current TOSCA template.
· The substitution mechanism allows a node instance to be represented by a service created simultaneously via a substitution template.
It is relevant to emphasize the cross-template usage, as only in this case we deal with templates defined at different design time-points, with potentially different editing and maintenance restrictions.
The TOSCA metamodel includes complex definitions used in types (e.g., Node Types, Relationship Types, Capability Types, Data Types, etc.), definitions and refinements (e.g., Requirement Definitions, Capability Definitions, Property and Parameter Definitions, etc.) and templates (e.g., Service Template, Node Template, etc.) all of which include their own list of reserved keynames that are sometimes marked as mandatory. If a keyname is marked as mandatory it MUST be defined in that particular definition context. In some definitions, certain keywords may be mandatory depending on the value of other keywords in the definition. In that case, the keyword will be marked as conditional and the condition will be explained in the description column. Note that in the context of type definitions, types may be used to derive other types, and keyname definitions MAY be inherited from parent types (according to the derivation rules of that type entity). If a keyname definition is inherited, the derived type does not have to provide such definition.
A TOSCA Service is specified by a TOSCA Service Template.
A TOSCA file contains definitions of building blocks for use in cloud applications or complete models of cloud applications. This section describes the top-level TOSCA keynames—along with their grammars—that are allowed to appear in a TOSCA file.
The following is the list of recognized keynames for a TOSCA file:
Keyname |
Mandatory |
Type |
Description |
tosca_definitions_version |
yes |
Defines the version of the TOSCA specification used in the TOSCA file |
|
profile |
no |
string |
The profile name that can be used by other TOSCA files to import the type definitions in this document. |
metadata |
no |
map of YAML values |
Defines a section used to declare additional metadata information. Domain-specific TOSCA profile specifications may define keynames that are mandatory for their implementations. |
description |
no |
Declares a description for this TOSCA file and its contents. |
|
dsl_definitions |
no |
N/A |
Defines reusable YAML macros (i.e., YAML alias anchors) for use throughout the TOSCA file. |
repositories |
no |
map of |
Declares the map of external repositories that contain artifacts that are referenced in the TOSCA file along with the addresses used to connect to them in order to retrieve the artifacts. |
imports |
no |
list of |
Declares a list of import statements pointing to external TOSCA files or well-known profiles. For example, these may be file locations or URIs relative to the TOSCA file within the same TOSCA CSAR file. |
artifact_types |
no |
map of |
This section contains amap of artifact type definitions for use in the TOSCA file and/or external TOSCA files. |
data_types |
no |
map of |
Declares a map of TOSCA Data Type definitions for use in the TOSCA file and/or external TOSCA files. |
capability_types |
no |
map of |
This section contains amap of capability type definitions for use in the TOSCA file and/or external TOSCA files. |
interface_types |
no |
map of |
This section contains amap of interface type definitions for use in the TOSCA file and/or external TOSCA files. |
relationship_types |
no |
map of |
This section contains a map of relationship type definitions for use in the TOSCA file and/or external TOSCA files. |
node_types |
no |
map of |
This section contains a map of node type definitions for use in the TOSCA file and/or external TOSCA files. |
group_types |
no |
map of |
This section contains a map of group type definitions for use in the TOSCA file and/or external TOSCA files. |
policy_types |
no |
map of |
This section contains a map of policy type definitions for use in the TOSCA file and/or external TOSCA files. |
service_template |
no |
Defines a template from which to create a mode/representation of an application or service. Service templates consist of node templates that represent the application’s or service’s components, as well as relationship templates representing relations between these components. |
|
Functions |
no |
map of function definitions |
This section contains a map of function definitions for use in the TOSCA file and/or external TOSCA files. |
The overall structure of a TOSCA file and its top-level keynames is shown below:
# Mandatory TOSCA version string tosca_definitions_version: <value> # Mandatory, see section 3.1 for usage profile: <string> # Optional, see section 3.2 for usage
# Optional metadata keyname: value pairs metadata:
# map of YAML values
# Optional description of the definitions inside the file. description: <template_ description>
dsl_definitions: # map of YAML alias anchors (or macros)
repositories: # map of external repository definitions which host TOSCA artifacts
imports: # ordered list of import definitions
artifact_types: # map of artifact type definitions
data_types: # map of datatype definitions
capability_types: # map of capability type definitions
interface_types # map of interface type definitions
relationship_types: # map of relationship type definitions
node_types: # map of node type definitions
group_types: # map of group type definitions
policy_types: # map of policy type definitions
functions: # map of function definitions`
service_template: # service template definition of the cloud application or service |
· The key “tosca_definitions_version” MUSTbe the first line of each TOSCA file..
· TOSCA files do not have to contain a service_template and MAY contain simply type definitions (e.g., Artifact, Interface, Capability, Node, Relationship Types, etc.), repository definitions, function definitions, or other import statements and be imported for use in other TOSCA files.
This mandatory element provides a means to specify the TOSCA version used within the TOSCA file. It is an indicator for the version of the TOSCA grammar that should be used to parse the remainder of the TOSCA file.
tosca_definitions_version |
tosca_definitions_version: <tosca_ version> |
TOSCA uses the following version strings for the various revisions of the TOSCA specification:
Version String |
TOSCA Specification |
tosca_2_0 |
TOSCA Version 2.0 |
tosca_simple_yaml_1_3 |
TOSCA Simple Profile in YAML Version 1.3 |
tosca_simple_yaml_1_2 |
TOSCA Simple Profile in YAML Version 1.2 |
tosca_simple_yaml_1_1 |
TOSCA Simple Profile in YAML Version 1.1 |
tosca_simple_yaml_1_0 |
TOSCA Simple Profile in YAML Version 1.0 |
The version for this specification is tosca_2_0.
Note that it is not mandatory for TOSCA Version 2.0 implementations to support older versions of the TOSCA specifications.
A TOSCA file designed using the TOSCA Version 2.0 specification:
tosca_definitions_version: tosca_2_0 |
The profile keyword is used to assign a profile name to the collection of types defined in this TOSCA file. TOSCA implementations use profile names to register known profiles into an internal repository. These profiles can then be imported by other TOSCA files using the profile keyword in their import statement.
profile |
profile: <string_value> |
TOSCA does not place any restrictions on the value of the profile name string. However, we encourage a Java-style reverse-domain notation with version as a best-practice convention.
The following is an example of a TOSCA file that defines TOSCA Simple Profile Version 2.0 types:
profile: org.oasis-open.tosca.simple:2.0 |
The following defines a domain-specific profile for Kubernetes:
profile: io.kubernetes:1.18 |
This keyname is used to associate domain-specific metadata with the Service Template. The metadata keyname allows a declaration of a map of keynames with values that can use all types supported by the YAML 1.2.2 recommended schemas [Yaml-1.2]. Specifically, the following types can be used for metadata values: map, seq, str, null, bool, int, float.
·
metadata |
metadata: <map_of_yaml_values> |
metadata: creation_date: 2015-04-14 date_updated: 2015-05-01 status: developmental |
This optional keyname provides a means to include single or multiline descriptions within a TOSCA template as a scalar string value.
description |
description: <description> |
Single line example
description: A simple example service template |
Multi-line example
description: "A multiline description using a quoted string” |
This optional keyname provides a section to define macros YAML-style macros for use in the TOSCA file.
dsl_definitions |
dsl_definitions: ... |
dsl_definitions: ubuntu_image_props: &ubuntu_image_props architecture: x86_64 type: linux distribution: ubuntu os_version: 14.04
redhat_image_props: &redhat_image_props architecture: x86_64 type: linux distribution: rhel os_version: 6.6 |
This optional keyname provides a section to define external repositories that may contain artifacts or other TOSCA files that might be referenced or imported by this TOSCA file.
repositories |
repositories: ... |
repositories: my_project_artifact_repo: description: development repository for TAR archives and Bash scripts url: http://mycompany.com/repository/myproject/ external_repo: https://foo.bar |
This optional keyname provides a way to import a one or more TOSCA profiles or other TOSCA files that contain reusable TOSCA type definitions (e.g., Node Types, Relationship Types, Artifact Types, etc.), function definitions, repository definitions, or other imports defined by other authors. This mechanism provides an effective way for companies and organizations to define domain-specific types and/or describe their software applications for reuse in other TOSCA files.
imports |
imports: - ... |
# An example import of TOSCA files from a location relative to the # file location of the TOSCA file declaring the import. imports: - relative_path/my_defns/my_typesdefs_1.yaml - url: my_defns/my_typesdefs_n.yaml repository: my_company_repo namespace: mycompany |
This optional keyname lists the Artifact Types that are defined by this TOSCA file..
artifact_types |
artifact_types: ... |
artifact_types: mycompany.artifacttypes.myFileType: derived_from: tosca.artifacts.File |
This optional keyname provides a section to define new data types in TOSCA.
data_types |
data_types: ... |
data_types: # A complex datatype definition simple_contactinfo_type: properties: name: type: string email: type: string phone: type: string
# datatype definition derived from an existing type full_contact_info: derived_from: simple_contact_info properties: street_address: type: string city: type: string state: type: string postalcode: type: string |
This optional keyname lists the Capability Types that provide the reusable type definitions that can be used to describe features of nodes that can be used to fulfill requirements of other nodes.
capability_types |
capability_types: ... |
capability_types: mycompany.mytypes.myCustomEndpoint: derived_from: tosca.capabilities.Endpoint properties: # more details ...
mycompany.mytypes.myCustomFeature: derived_from: tosca.capabilities.Feature properties: # more details ... |
This optional keyname lists the Interface Types that provide the reusable type definitions that can be used to describe operations exposed by TOSCA relationships and nodes.
interface_types |
interface_types: ... |
interface_types: mycompany.interfaces.service.Signal: operations: signal_begin_receive: description: Operation to signal start of some message processing. signal_end_receive: description: Operation to signal end of some message processed. |
This optional keyname lists the Relationship Types that provide the reusable type definitions that can be used to describe dependent relationships between nodes.
relationship_types |
relationship_types: ... |
relationship_types: mycompany.mytypes.myCustomClientServerType: derived_from: tosca.relationships.HostedOn properties: # more details ... mycompany.mytypes.myCustomConnectionType: derived_from: tosca.relationships.ConnectsTo properties: # more details ... |
This optional keyname lists the Node Types that provide the reusable type definitions for nodes in a service.
node_types |
node_types: ... |
node_types: my_webapp_node_type: derived_from: WebApplication properties: my_port: type: integer
my_database_node_type: derived_from: Database capabilities: mytypes.myfeatures.transactSQL |
This optional keyname lists the Group Types that are defined by this TOSCA file.
group_types |
group_types: ... |
group_types: mycompany.mytypes.myScalingGroup: derived_from: tosca.groups.Root |
This optional keyname lists the Policy Types that are defined by this TOSCA file.
policy_types |
policy_types: ... |
policy_types: mycompany.mytypes.myScalingPolicy: derived_from: tosca.policies.Scaling |
A profile is a named collection of TOSCA type definitions, artifacts, and service templates that logically belong together. One can think of TOSCA profiles as platform libraries exposed by the TOSCA orchestration platform and made available to all services that use that platform. Profiles in TOSCA are similar to libraries in traditional computer programming languages.
Profiles contain a collection of pre-defined components that can be used by service designers to compose complex service templates, Entities defined in TOSCA profiles are used as follows:
· Types defined in a TOSCA profile provide reusable building blocks from which services can be composed.
· Artifacts and service templates defined in a TOSCA profile provide implementations for the TOSCA types defined in the profile. Whereas artifacts provide interface operation implementations for concrete nodes and relationships, service templates defined in TOSCA profiles are intended to implement abstract nodes through substitution mapping.
TOSCA implementations can organize supported profiles in a catalog to allow other service templates to import those profiles by profile name. This avoids the need for every service that use those profiles to include the profile type definitions in their service definition packages.
Version 1.x of the TOSCA specification included a collection of normative type definitions for building cloud applications. This collection of type definitions was defined as the TOSCA Simple Profile. Implementations of TOSCA Version 1.x were expected to include implementations for the types defined in the TOSCA Simple Profile, and service templates defined using TOSCA Version 1.x implicitly imported the corresponding TOSCA Simple Profile version.
Starting with TOSCA Version 2.0, the TOSCA Simple Profile type definitions are no longer part of the TOSCA standard and support for the TOSCA Simple Profile is no longer mandatory. Instead, the definition of the TOSCA Simple Profile has been moved to an OASIS Open Github repository with the goal of being maintained by the TOSCA community and governed as an open-source project. In addition, TOSCA Version 2.0 removes the implicit import of the TOSCA Simple Profile. Service templates that want to continue to use the TOSCA Simple Profile type definitions must explicitly import that profile.
Eliminating mandatory support for the TOSCA Simple Profile makes it easier for TOSCA to be used for additional application domains. For example, the European Telecommunications Standards Institute (ETSI) has introduced a TOSCA profile for Network Functions Virtualization defines Virtualized Network Function Descriptors (VNFDs), Network Service Descriptors (NSDs) and a Physical Network Function Descriptors (PNFDs).
We should give a couple of additional examples.
A TOSCA file defines a TOSCA Profile if the profile keyword is used in that service template. The value of the profile keyword defines the name for the profile, which allows other service templates to import the profile by name.
TOSCA does not impose naming conventions for profile names, but as a best practice we recommend a domain-name-like structure as used for Java package naming. For example, the following profile statement is used to define TOSCA Simple Profile Version 2.0 types:
profile: org.oasis-open.tosca.simple:2.0 |
TOSCA parsers MUST process profile definitions according to the following rules:
· TOSCA files that define a profile (i.e., that contain a profile keyname) MUST NOT also define a service template.
· If the parser encounters the profile keyname in a TOSCA file, then the corresponding profile name will be applied to all types defined in that file as well as to types defined in any imported TOSCA files.
· If one of those imported files also defines the profile keyname—and that profile name is different from the name of the importing profile—then that profile name overrides the profile name value from that point in the import tree onward, recursively.
· TOSCA service templates defined in profiles MUST advertise substitution mapping to allow them to be used as implementations for abstract nodes defined using profile types.
TOSCA Profiles are likely to evolve over time and profile designers will release different versions of their profiles. For example, the TOSCA Simple Profile has gone through minor revisions with each release of the TOSCA Version 1 standard. It is expected that profile designers will use a version qualifier to distinguish between different versions of their profiles, and service template designers must use the proper string name to make sure they import the desired versions of these profiles.
Do we impose a structure on profile names that distinguishes the version qualifier from the base profile name? If so, is there a specific separator character or string (in which case the use of the separator must be escaped somehow (or disallowed) in profile names.
When multiple versions of the same profile exist, it is possibly that service templates could mix and match different versions of a profile in the same service definition. The following code snippets illustrate this scenario:
Assume a profile designer creates version 1 of a base profile that defines (among other things) a Host capability type and a corresponding HostedOn relationship type as follows:
tosca_definitions_version: tosca_2_0 profile: org.base.v1 capability_types: Host: description: Hosting capability relationship_types: HostedOn: valid_capability_types: [ Host ] |
Now let’s assume a different profile designer creates a platform-specific profile that defines (among other things) a Platform node type. The Platform node type defines a capability of type Host. Since the Host capability is defined in the org.base.v1 profile, that profile must be imported as shown in the snippet below:
tosca_definitions_version: tosca_2_0 profile: org.platform imports: - profile: org.base.v1 namespace: p1 node_types: Platform: capabilities: host: type: p1:Host |
At some later point of time, the original profile designer updates the org.base profile to Version 2. The updated version of this profile just adds a Credential data type (in addition to defining the Host capability type and the HostedOn relationship type), as follows:
tosca_definitions_version: tosca_2_0 profile: org.base.v2 capability_types: Host: description: Hosting capability relationship_types: HostedOn: valid_capability_types: [ Host ] data_types: Credential: properties: key: type: string |
Finally, let’s assume a service designer creates a template for a service that is to be hosted on the platform defined in the org.platform profile. The template introduces a Service node type that has a requirement for the platform’s Host capability. It also has a credential property of type Credential as defined in org.base.v2:
tosca_definitions_version: tosca_2_0 imports: - profile: org.base.v2 namespace: p2 - profile: org.platform namespace: pl node_types: Service: properties: credential: type: p2:Credential requirements: - host: capability: p2:Host relationship: p2:HostedOn service_template: node_templates: service: type: Service properties: credential: key: password requirements: - host: platform platform: type: pl:Platform |
This service template is invalid, since the platform node template does not define a capability of a type that is compatible with the valid_capability_types specified by the host requirement in the service node template. TOSCA grammar extensions are needed to specify that the Host capability type defined in org.base.v2 is the same as the Host capability type defined in org.base.v1
The example in this section illustrates a general version compatibility issue that exists when different versions of the same profile are used in a TOSCA service.
A number of suggestions for these extensions are currently being discussed. Grammar extensions will be included in this document one they are agreed upon.
An import definition is used within a TOSCA file to locate and uniquely name another TOSCA file or TOSCA profile that has type, repository, and function definitions to be imported (included) into another TOSCA file.
The following is the list of recognized keynames for a TOSCA import definition:
Keyname |
Mandatory |
Type |
Description |
url |
conditional |
The url that references a service template to be imported. An import statement must include either a url or a profile, but not both. |
|
profile |
conditional |
string |
The profile name that references a named type profile to be imported. An import statement must include either a url or a profile, but not both. |
repository |
conditional |
The optional symbolic name of the repository definition where the imported file can be found as a string. The repository name can only be used when a url is specified. |
|
namespace |
no |
The optional name of the namespace into which to import the type definitions from the imported template or profile. |
Import definitions have one the following grammars:
When using the single-line grammar, the url keyword is assumed:
imports: - <URI_1> - <URI_2> |
The following multi-line grammar can be used for importing TOSCA files:
imports: - url: <file_URI> repository: <repository_name> namespace: <namespace_name> |
The following multi-line grammar can be used for importing TOSCA profiles:
imports: - profile: <profile_name> namespace: <namespace_name> |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· file_uri: contains the URL that references the service template file to be imported as a string.
· repository_name: represents the optional symbolic name of the repository definition where the imported file can be found as a string.
· profile_name: the name of the well-known profile to be imported.
· namespace_name: represents the optional name of the namespace into which type definitions will be imported. The namespace name can be used to form a namespace-qualified name that uniquely references type definitions from the imported file or profile. If no namespace name is specified, type definitions will be imported into the root namespace.
TOSCA Orchestrators, Processors and tooling SHOULD handle import statements as follows:
If the profile keyname is used in the import definition, then the TOSCA orchestrator or processor SHOULD attempt to import the profile by name:
· If <profile_name> represents the name of a profile that is known to the TOSCA orchestrator or processor, then it SHOULD cause the Profile Type definitions to be imported.
· If <profile_name> is not known, the import SHOULD be considered a failure.
If the url keyname is used, the TOSCA orchestrator or processor SHOULD attempt to import the file referenced by <file_URI> as follows:
· If the <file_URI> includes a URL scheme (e.g. file: or https:) then<file_URI> is considered to be a network accessible resource. If the resource identified by <file_URL> represents a valid TOSCA file, then it SHOULD cause the remote Service Template to be imported.
– Note that if in addition to a URL with a URL scheme, the import definition also specifies a <repository_name> (using the repository key), then that import definition SHOULD be considered invalid.
· If the <file_URI> does not include a URL scheme, it is a considered a relative path URL. The TOSCA orchestrator or processor SHOULD handle such a <file_URI> as follows:
– If the import definition also specifies a <repository_name> (using the repository keyname), then <file_URI> refers to the path name of a file relative to the root of the named repository
– If the import definition does not specify a <profile_name> then <file_URI> refers to a TOSCA file located in the repository that contains the Service Template file that includes the import definition. If the importing service template is located in a CSAR file, then that CSAR file should be treated as the repository in which to locate the service template file that must be imported.
· If <file_URI> starts with a leading slash (‘/’) then <file_URI> specifies a path name starting at the root of the repository.
· If <file_URI> does not start with a leading slash, then <file_URI> specifies a path that is relative to the importing document’s location within the repository. Double dot notation (‘../’) can be used to refer to parent directories in a file path name.
· If <file_URI> does not reference a valid TOSCA file file, then the import SHOULD be considered a failure.
The first example shows how to use an import definition import a well-known profile by name:
# Importing a profile imports: - profile: org.oasis-open.tosca.simple:2.0 |
The next example shows an import definition used to import a network-accessible resource using the https protocol:
# Absolute URL with scheme imports: - url: https://myorg.org/tosca/types/mytypes.yaml |
The following represents shows an import definition used to import a service template in the same repository as the importing template. The template to be imported is referenced using a path name that is relative to the location of the importing template. This example shows the short notation:
# Short notation supported imports: - ../types/mytypes.yaml |
The following shows the same example but using the long notation:
# Long notation imports: - url: ../types/mytypes.yaml |
The following example shows how to import service templates using absolute path names (i.e. path names that start at the root of the repository):
# Root file imports: - url: /base.yaml |
And finally, the following shows how to import templates from a repository that is different than the repository that contains the importing template:
# External repository imports: - url: types/mytypes.yaml repository: my_repository |
When importing TOSCA files or TOSCA profiles, there exists a possibility for name collision. For example, an imported file may define a node type with the same name as a node type defined in the importing file.
For example, let say we have two TOSCA files, A and B, both of which contain a Node Type definition for “MyNode”:
TOSCA File B
tosca_definitions_version: tosca_2_0 description: TOSCA File B
node_types: MyNode: derived_from: SoftwareComponent properties: # omitted here for brevity capabilities: # omitted here for brevity |
TOSCA File A
tosca_definitions_version: tosca_2_0 description: TOSCA File A
imports: - url: /templates/ServiceTemplateB.yaml
node_types: MyNode: derived_from: Root properties: # omitted here for brevity capabilities: # omitted here for brevity
service_template: node_templates: my_node: type: MyNode |
As you can see, TOSCA file A imports TOSCA file B which results in duplicate definitions of the MyNode node type. In this example, it is not clear which type is intended to be used for the my_node node template.
To address this issue, TOSCA uses the concept of namespaces:
· Each TOSCA file defines a root namespace for all type definitions defined in that template. Root namespaces are unnamed.
· When a TOSCA file imports other templates, it has two options:
– It can import any type definitions from the imported templates into its root namespace
– Or it can import type definitions from the imported templates into a separate named namespace. This is done using the namespace keyname in the associated import statement. When using types imported into a named namespace, those type names must be qualified using the namespace name.
The following snippets update the previous example using namespaces to disambiguate between the two MyNode type definitions. This first snippet shows the scenario where the MyNode definition from TOSCA file B is intended to be used:
tosca_definitions_version: tosca_2_0
description: TOSCA file A
imports:
- url: /templates/ServiceTemplateB.yaml
namespace: templateB
node_types:
MyNode:
derived_from: Root
properties:
# omitted here for brevity
capabilities:
# omitted here for brevity
service_template:
node_templates:
my_node:
type: templateB:MyNode
The second snippet shows the scenario where the MyNode definition from TOSCA file A is intended to be used:
tosca_definitions_version: tosca_2_0
description: TOSCA file A
imports:
- url: /templates/ServiceTemplateB.yaml
namespace: templateB
node_types:
MyNode:
derived_from: Root
properties:
# omitted here for brevity
capabilities:
# omitted here for brevity
service_template:
node_templates:
my_node:
type: MyNode
In many scenarios, imported TOSCA files may in turn import their own TOSCA files, and introduce their own namespaces to avoid name collisions. In those scenarios, nested namespace names are used to uniquely identify type definitions in the import tree.
The following example shows a mytypes.yaml TOSCA file that imports a Kubernetes profile into the k8s namespace. It defines a SuperPod node type that derives from the Pod node type defined in that Kubernetes profile:
tosca_definitions_version: tosca_2_0
description: mytypes.yaml
imports:
- profile: io.kubernetes:1.18
namespace: k8s
node_types:
MyNode: {}
SuperPod:
derived_from: k8s:Pod
The mytypes.yaml template is then imported into the main.yaml TOSCA file, which defines both a node template of type SuperPod as well as a node template of type Pod. Nested namespace names are used to identify the Pod node type from the Kubernetes profile:
tosca_definitions_version: tosca_2_0
description: main.yaml
imports:
- url: mytypes.yaml
namespace: my
service_template:
node_templates:
mynode:
type: my:MyType
pod:
type: my:k8s:Pod
Within each namespace, names must be unique. This means the following:
· Duplicate local names (i.e., within the same TOSCA file SHALL be considered an error. These include, but are not limited to duplicate names found for the following definitions:
– Repositories (repositories)
– Data Types (data_types)
– Node Types (node_types)
– Relationship Types (relationship_types)
– Capability Types (capability_types)
– Artifact Types (artifact_types)
– Interface Types (interface_types)
· Duplicate Template names within a Service Template SHALL be considered an error. These include, but are not limited to duplicate names found for the following template types:
– Node Templates (node_templates)
– Relationship Templates (relationship_templates)
– Inputs (inputs)
– Outputs (outputs)
· Duplicate names for the following keynames within Types or Templates SHALL be considered an error. These include, but are not limited to duplicate names found for the following keynames:
– Properties (properties)
– Attributes (attributes)
– Artifacts (artifacts)
– Requirements (requirements)
– Capabilities (capabilities)
– Interfaces (interfaces)
– Policies (policies)
– Groups (groups)
A repository definition defines an external repository which contains deployment and implementation artifacts that are referenced within the TOSCA file.
The following is the list of recognized keynames for a TOSCA repository definition:
Keyname |
Mandatory |
Type |
Description |
description |
no |
The optional description for the repository. |
|
url |
yes |
The mandatory URL or network address used to access the repository. |
Repository definitions have one the following grammars:
<repository_name>: <repository_address> |
description: <repository_description> url: <repository_address> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· repository_name: represents the mandatory symbolic name of the repository as a string.
· repository_description: contains an optional description of the repository.
· repository_address: represents the mandatory URL of the repository as a string.
The following represents a repository definition:
repositories: my_code_repo: description: My project’s code repository in GitHub url: https://github.com/my-project/ |
This optional element provides a means include single or multiline descriptions within a TOSCA template as a scalar string value.
The following keyname is used to provide a description within the TOSCA specification:
description |
Description definitions have the following grammar:
description: <description_string> |
Simple descriptions are treated as a single literal that includes the entire contents of the line that immediately follows the description key:
description: This is an example of a single line description (no folding). |
The YAML “folded” style may also be used for multi-line descriptions which “folds” line breaks as space characters.
description: > This is an example of a multi-line description using YAML. It permits for line breaks for easier readability...
if needed. However, (multiple) line breaks are folded into a single space character when processed into a single string value. |
· Use of “folded” style is discouraged for the YAML string type apart from when used with the description keyname. .
This optional element provides a means to include optional metadata as a map of strings.
The following keyname is used to provide metadata within the TOSCA specification:
metadata |
Metadata definitions have the following grammar:
metadata: map of <string> |
metadata: foo1: bar1 foo2: bar2 ... |
· Data provided within metadata, wherever it appears, MAY be ignored by TOSCA Orchestrators and SHOULD NOT affect runtime behavior.
TBD.
TOSCA provides a type system to describe possible building blocks to construct a service template (i.e. for the nodes, relationship, group and policy templates, and the data, capabilities, interfaces, and artifacts used in the node and relationship templates). TOSCA types are reusable TOSCA entities and are defined in their specific sections in the service template, see Section 4.2.1 Service Template definition.
Next, in Section 4.2.5.2 Common keynames in type definitions we present the definitions of common keynames that are used by all TOSCA types. Type-specific definitions for the different TOSCA type entities are presented further in the document:
· Node Type in Section 4.3.1 Node Type.
· Relationship Type in Section 4.3.3 Relationship Type.
· Interface Type in Section 4.3.6.1 Interface Type.
· Capability Type in Section 4.3.5.1 Capability Type.
· Requirement Type in Section 4.3.5.4 Requirement Type.
· Data Type in Section 4.4.4 Data Type.
· Artifact Type in Section 4.3.7.1 Artifact Type.
· Group Type in Section 4.6.1 Group Type.
· Policy Type in Section 4.6.3 Policy Type.
To simplify type creation and to promote type extensibility TOSCA allows the definition of a new type (the derived type) based on another type (the parent type). The derivation process can be applied recursively, where a type may be derived from a long list of ancestor types (the parent, the parent of the parent, etc).
Unless specifically stated in the derivation rules, when deriving new types from parent types the keyname definitions are inherited from the parent type. Moreover, the inherited definitions may be refined according to the derivation rules of that particular type entity.
For definitions that are not inherited, a new definition MUST be provided (if the keyname is mandatory) or MAY be provided (if the keyname is not mandatory). If not provided, the keyname remains undefined. For definitions that are inherited, a refinement of the inherited definition is not mandatory even for mandatory keynames (since it has been inherited). A definition refinement that is exactly the same as the definition in the parent type does not change in any way the inherited definition. While unnecessary, it is not wrong.
The following are some generic derivation rules used during type derivation (the specific rules of each TOSCA type entity are presented in their respective sections):
· If not refined, usually a keyname/entity definition, is inherited unchanged from the parent type, unless explicitly specified in the rules that it is “not inherited”.
· New entities (such as properties, attributes, capabilities, requirements, interfaces, operations, notification, parameters) may be added during derivation.
· Already defined entities that have a type may be redefined to have a type derived from the original type.
· New validation clauses are added to already defined keynames/entities (i.e. the defined validation clauses do not replace the validation clause defined in the parent type but are added to it).
· Some definitions must be totally flexible, so they will overwrite the definition in the parent type.
· Some definitions must not be changed at all once defined (i.e. they represent some sort of “signature” fundamental to the type).
The following keynames are used by all TOSCA type entities in the same way. This section serves to define them at once.
The following is the list of recognized keynames used by all TOSCA type definitions:
Keyname |
Mandatory |
Type |
Description |
derived_from |
no |
An optional parent type name from which this type derives. |
|
version |
no |
An optional version for the type definition. |
|
metadata |
no |
Defines a section used to declare additional metadata information. |
|
description |
no |
An optional description for the type. |
The common keynames in type definitions have the following grammar:
<type_name>: derived_from: <parent_type_name> version: <version_number> metadata: description: <type_description> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· parent_type_name: represents the optional parent type name.
· version_number: represents the optional TOSCA version number for the type.
· entity_description: represents the optional description string for the type.
· metadata_map: represents the optional metadata map of string.
During type derivation the common keyname definitions use the following rules:
· derived_from: obviously, the definition is not inherited from the parent type. If not defined, it remains undefined and this type does not derive from another type. If defined, then this type derives from another type, and all its keyname definitions must respect the derivation rules of the type entity.
· version: the definition is not inherited from the parent type. If undefined, it remains undefined.
· metadata: the definition is not inherited from the parent type. If undefined, it remains undefined.
· description: the definition is not inherited from the parent type. If undefined, it remains undefined.
This section defines the service template of a TOSCA file. The main ingredients of the service template are node templates representing components of the application and relationship templates representing links between the components. These elements are defined in the nested node_templates section and the nested relationship_templates sections, respectively. Furthermore, a service template allows for defining input parameters, output parameters as well as grouping of node templates.
The following is the list of recognized keynames for a TOSCA service template:
Keyname |
Mandatory |
Type |
Description |
description |
no |
The optional description for the service template. |
|
inputs |
no |
map of |
An optional map of input parameters (i.e., as parameter definitions) for the service template. |
node_templates |
yes |
map of |
A mandatory map of node template definitions for the service template. |
relationship_templates |
no |
map of |
An optional map of relationship templates for the service template. |
groups |
no |
map of |
An optional map of Group definitions whose members are node templates defined within this same service template. |
policies |
no |
list of |
An optional list of Policy definitions for the service template. |
outputs |
no |
map of |
An optional map of output parameters (i.e., as parameter definitions) for the service template. |
substitution_mappings |
no |
substitution_mapping |
An optional declaration that exports the service template as an implementation of a Node type.
This also includes the mappings between the external Node Types capabilities and requirements to existing implementations of those capabilities and requirements on Node templates declared within the service template. |
workflows |
no |
map of imperative workflow definitions |
An optional map of imperative workflow definition for the service template. |
The overall grammar of the service_template section is shown below.Detailed grammar definitions are provided in subsequent subsections.
service_template: description: <template_description> inputs: <input_parameters> outputs: <output_parameters> node_templates: <node_templates> relationship_templates: <relationship_templates> groups: <group_definitions> policies: - <policy_definition_list> workflows: <workflows> # Optional declaration that exports the service template # as an implementation of a Node Type. substitution_mappings: <substitution_mappings> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· template_description: represents the optional description string for service template.
· input_parameters: represents the optional map of input parameter definitions for the service template.
· output_parameters: represents the optional map of output parameter definitions for the service template.
· group_definitions: represents the optional map of group definitions whose members are node templates that also are defined within this service template.
· policy_definition_list: represents the optional list of sequenced policy definitions for the service template.
· workflows: represents the optional map of imperative workflow definitions for the service template.
· node_templates: represents the mandatory map of node template definitions for the service template.
· relationship_templates: represents the optional map of relationship templates for the service template.
· node_type_name: represents the optional name of a Node Type that the service template implements as part of the substitution_mappings.
· map_of_capability_mappings_to_expose: represents the mappings that expose internal capabilities from node templates (within the service template) as capabilities of the Node Type definition that is declared as part of the substitution_mappings.
· map_of_requirement_mappings_to_expose: represents the mappings of link requirements of the Node Type definition that is declared as part of the substitution_mappings to internal requirements implementations within node templates (declared within the service template).
More detailed explanations for each of the service template grammar’s keynames appears in the sections below.
The inputs section provides a means to define parameters using TOSCA parameter definitions, their allowed values via validation clauses and default values within a TOSCA template. Input parameters defined in the inputs section of a service template can be mapped to properties of node templates or relationship templates within the same service template and can thus be used for parameterizing the instantiation of the service template.
When deploying a service from the service template, values must be provided for all mandatory input parameters that have no default value defined. If no input is provided, then the default value is used.
The grammar of the inputs section is as follows:
inputs: |
This section provides a set of examples for the single elements of a service template.
Simple inputs example without any validation clauses:
inputs: fooName: type: string description: Simple string parameter without a validation clause. default: bar |
Example of inputs with a validation clause:
inputs: SiteName: type: string description: String parameter with validation clause. default: My Site validation: { $min_length: [ $value, 9 ] } |
The node_templates section lists the Node Templates that describe the (software) components that are used to compose cloud applications.
The grammar of the node_templates section is a follows:
node_templates: ... |
Example of node_templates section:
node_templates: my_webapp_node_template: type: WebApplication
my_database_node_template: type: Database |
The relationship_templates section lists the Relationship Templates that describe the relations between components that are used to compose cloud applications.
Note that in TOSCA, the explicit definition of relationship templates as it was required in TOSCA v1.0 is optional, since relationships between nodes get implicitly defined by referencing other node templates in the requirements sections of node templates.
The grammar of the relationship_templates section is as follows:
relationship_templates: <relationship_template_defn_1> ... |
Example of relationship_templates section:
relationship_templates: my_connectsto_relationship: type: tosca.relationships.ConnectsTo interfaces: Configure: inputs: speed: { $$get_attribute: [ SELF, SOURCE, connect_speed ] } |
The outputs section provides a means to define the output parameters that are available from a TOSCA service template. It allows for exposing attributes of node templates or relationship templates within the containing service_template to users of a service.
The grammar of the outputs section is as follows:
outputs: |
Example of the outputs section:
outputs: server_address: description: The first private IP address for the provisioned server. value: { $get_attribute: [ node5, networks, private, addresses, 0 ] } |
The groups section allows for grouping one or more node templates within a TOSCA Service Template and for assigning special attributes like policies to the group.
The grammar of the groups section is as follows:
groups: ... |
The following example shows the definition of three Compute nodes in the node_templates section of a service_template as well as the grouping of two of the Compute nodes in a group server_group_1.
node_templates: server1: type: tosca.nodes.Compute # more details ...
server2: type: tosca.nodes.Compute # more details ...
server3: type: tosca.nodes.Compute # more details ...
groups: # server2 and server3 are part of the same group server_group_1: type: tosca.groups.Root members: [ server2, server3 ] |
The policies section allows for declaring policies that can be applied to entities in the service template.
The grammar of the policies section is as follows:
policies: - <policy_defn_1> - ... - <policy_defn_n> |
The following example shows the definition of a placement policy.
policies: - my_placement_policy: type: mycompany.mytypes.policy.placement |
The grammar of a requirement_mapping is as follows:
<requirement_name>: [ <node_template_name>, <node_template_requirement_name> ] |
The multi-line grammar is as follows :
<requirement_name>: mapping: [ <node_template_name>, <node_template_capability_name> ] properties: <property_name>: <property_value> |
· requirement_name: represents the name of the requirement as it appears in the Node Type definition for the Node Type (name) that is declared as the value for on the substitution_mappings’ “node_type” key.
· node_template_name: represents a valid name of a Node Template definition (within the same service_template declaration as the substitution_mapping is declared).
· node_template_requirement_name: represents a valid name of a requirement definition within the <node_template_name> declared in this mapping.
The following example shows the definition of a placement policy.
service_template:
inputs: cpus: type: integer validation: { $less_than: [ $value, 2 ] } # OR use “defaults” key
substitution_mappings: node_type: MyService properties: # Do not care if running or matching (e.g., Compute node) # get from outside? Get from contsraint? num_cpus: cpus # Implied “PUSH” # get from some node in the topology… num_cpus: [ <node>, <cap>, <property> ] # 1) Running architecture: # a) Explicit value: { $get_property: [some_service, architecture] } # b) implicit value: [ some_service, <req | cap name>, <property name> architecture ] default: “amd” # c) INPUT mapping? ??? # 2) Catalog (Matching) architecture: contraints: equals: “x86”
capabilities: bar: [ some_service, bar ] requirements: foo: [ some_service, foo ]
node_templates: some_service: type: MyService properties: rate: 100 capabilities: bar: ... requirements: - foo: ...
|
A Node Type is a reusable entity that defines the type of one or more Node Templates. As such, a Node Type defines the structure of observable properties and attributes, the capabilities and requirements of the node as well as its supported interfaces and the artifacts it uses.
The Node Type is a TOSCA type entity and has the common keynames listed in Section 4.2.5.2 Common keynames in type definitions. In addition, the Node Type has the following recognized keynames:
Keyname |
Mandatory |
Type |
Description |
properties |
no |
map of |
An optional map of property definitions for the Node Type. |
attributes |
no |
map of |
An optional map of attribute definitions for the Node Type. |
capabilities |
no |
map of |
An optional map of capability definitions for the Node Type. |
requirements |
no |
list of |
An optional list of requirement definitions for the Node Type. |
interfaces |
no |
map of |
An optional map of interface definitions supported by the Node Type. |
artifacts |
no |
map of |
An optional map of artifact definitions for the Node Type. |
Node Types have following grammar:
derived_from: <parent_node_type_name> version: <version_number> metadata: description: <node_type_description> properties: attributes: capabilities: requirements: interfaces: artifacts: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· node_type_name: represents the mandatory symbolic name of the Node Type being declared.
· parent_node_type_name: represents the name (string) of the Node Type this Node Type definition derives from (i.e. its parent type).
· version_number: represents the optional TOSCA version number for the Node Type.
· node_type_description: represents the optional description string for the corresponding node_type_name.
· property_definitions: represents the optional map of property definitions for the Node Type.
· attribute_definitions: represents the optional map of attribute definitions for the Node Type.
· capability_definitions: represents the optional map of capability definitions for the Node Type.
· requirement_definitions: represents the optional list of requirement definitions for the Node Type.
· interface_definitions: represents the optional map of one or more interface definitions supported by the Node Type.
· artifact_definitions: represents the optional map of artifact definitions for the Node Type
During Node Type derivation the keyname definitions follow these rules:
· properties: existing property definitions may be refined; new property definitions may be added.
· attributes: existing attribute definitions may be refined; new attribute definitions may be added.
· capabilities: existing capability definitions may be refined; new capability definitions may be added.
· requirements: existing requirement definitions may be refined; new requirement definitions may be added.
· interfaces: existing interface definitions may be refined; new interface definitions may be added.
· artifacts: existing artifact definitions (identified by their symbolic name) may be redefined; new artifact definitions may be added.
– note that an artifact is created for a specific purpose and corresponds to a specific file (with e.g. a path name and checksum); if it cannot meet its purpose in a derived type then a new artifact should be defined and used.
– thus, if an artifact defined in a parent node type does not correspond anymore with the needs in the child node type, its definition may be completely redefined; thus, an existing artifact definition is not refined, but completely overwritten.
· Requirements are intentionally expressed as a list of TOSCA Requirement definitions which SHOULD be resolved (processed) in sequence by TOSCA Orchestrators.
my_company.my_types.my_app_node_type: derived_from: tosca.nodes.SoftwareComponent description: My company’s custom applicaton properties: my_app_password: type: string description: application password validation: $and: - { $min_length: [ $value, 6 ] } - { $max_length: [ $value, 10 ] } attributes: my_app_port: type: integer description: application port number requirements: - some_database: capability: EndPoint.Database node: Database relationship: ConnectsTo |
A Node Template specifies the occurrence of a manageable component as part of an application’s topology model which is defined in a TOSCA Service Template. A Node Template is an instance of a specified Node Type and can provide customized properties, relationships, or interfaces that complement and change the defaults provided by its Node Type.
The following is the list of recognized keynames for a TOSCA Node Template definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory name of the Node Type the Node Template is based upon. |
|
description |
no |
An optional description for the Node Template. |
|
metadata |
no |
Defines a section used to declare additional metadata information. |
|
directives |
no |
list of string |
An optional list of directive values to provide processing instructions to orchestrators and tooling. |
properties |
no |
map of |
An optional map of property value assignments for the Node Template. |
attributes |
no |
map of |
An optional map of attribute value assignments for the Node Template. |
requirements |
no |
list of |
An optional list of requirement assignments for the Node Template. |
capabilities |
no |
map of |
An optional map of capability assignments for the Node Template. |
interfaces |
no |
map of |
An optional map of interface assignments for the Node Template. |
artifacts |
no |
map of
|
An optional map of artifact definitions for the Node Template. |
node_filter |
no |
The optional filter definition that TOSCA orchestrators will use to select the correct target node. |
|
copy |
no |
The optional (symbolic) name of another node template to copy into (all keynames and values) and use as a basis for this node template. |
type: <node_type_name> description: <node_template_description> directives: [<directives>] metadata: properties: attributes: requirements: capabilities: interfaces: artifacts: node_filter: copy: <source_node_template_name> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· node_template_name: represents the mandatory symbolic name of the Node Template being declared.
· node_type_name: represents the name of the Node Type the Node Template is based upon.
· node_template_description: represents the optional description string for Node Template.
· directives: represents the optional list of processing instruction keywords (as strings) for use by tooling and orchestrators.
· property_assignments: represents the optional map of property assignments for the Node Template that provide values for properties defined in its declared Node Type.
· attribute_assignments: represents the optional map of attribute assignments for the Node Template that provide values for attributes defined in its declared Node Type.
· requirement_assignments: represents the optional list of requirement assignments for the Node Template for requirement definitions provided in its declared Node Type.
· capability_assignments: represents the optional map of capability assignments for the Node Template for capability definitions provided in its declared Node Type.
· interface_assignments: represents the optional map of interface assignments for the Node Template interface definitions provided in its declared Node Type.
· artifact_definitions: represents the optional map of artifact definitions for the Node Template that augment those provided by its declared Node Type.
· node_filter_definition: represents the optional node filter TOSCA orchestrators will use for selecting a matching node template.
· source_node_template_name: represents the optional (symbolic) name of another node template to copy into (all keynames and values) and use as a basis for this node template.
· The source node template provided as a value on the copy keyname MUST NOT itself use the copy keyname (i.e., it must itself be a complete node template description and not copied from another node template).
node_templates: mysql: type: tosca.nodes.DBMS.MySQL properties: root_password: { $get_input: my_mysql_rootpw } port: { $get_input: my_mysql_port } requirements: - host: db_server interfaces: Standard: operations: configure: scripts/my_own_configure.sh |
A Relationship Type is a reusable entity that defines the type of one or more relationships between Node Types or Node Templates.
The Relationship Type is a TOSCA type entity and has the common keynames listed in Section 4.2.5.2 Common keynames in type definitions. In addition, the Relationship Type has the following recognized keynames:
Keyname |
Mandatory |
Definition/Type |
Description |
properties |
no |
map of |
An optional map of property definitions for the Relationship Type. |
attributes |
no |
map of |
An optional map of attribute definitions for the Relationship Type. |
interfaces |
no |
map of |
An optional map of interface definitions supported by the Relationship Type. |
valid_capability_types
|
no |
list of string |
An optional list of one or more names of Capability Types that are valid targets for this relationship. If undefined, all Capability Types are valid. |
valid_target_node_types |
no |
list of string |
An optional list of one or more names of Node Types that are valid targets for this relationship. If undefined, all Node Types are valid targets. |
valid_source_node_types |
no |
list of string |
An optional list of one or more names of Node Types that are valid sources for this relationship. If undefined, all Node Types are valid sources. |
Relationship Types have following grammar:
derived_from: <parent_relationship_type_name> version: <version_number> metadata: description: <relationship_description> properties: attributes: interfaces: valid_capability_types: [ <capability_type_names> ] valid_target_node_types: [ <target_node_type_names> ] valid_source_node_types: [ <source_node_type_names> ] |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· relationship_type_name: represents the mandatory symbolic name of the Relationship Type being declared as a string.
· parent_relationship_type_name: represents the name (string) of the Relationship Type this Relationship Type definition derives from (i.e., its “parent” type).
· relationship_description: represents the optional description string for the corresponding relationship_type_name.
· version_number: represents the optional TOSCA version number for the Relationship Type.
· property_definitions: represents the optional map of property definitions for the Relationship Type.
· attribute_definitions: represents the optional map of attribute definitions for the Relationship Type.
· interface_definitions: represents the optional map of interface definitions supported by the Relationship Type.
· capability_type_names: represents the optional list of valid target Capability Types for the relationship; if undefined, the valid target types are not restricted at all (i.e., all Capability Types are valid).
· target_node_type_names: represents the optional list of valid target Node Types for the relationship; if undefined, the valid types are not restricted at all (i.e., all Node Types are valid).
· source_node_type_names: represents the optional list of valid source Node Types for the relationship; if undefined, the valid types are not restricted at all (i.e., all Node Types are valid).
During Relationship Type derivation the keyname definitions follow these rules:
· properties: existing property definitions may be refined; new property definitions may be added.
· attributes: existing attribute definitions may be refined; new attribute definitions may be added.
· interfaces: existing interface definitions may be refined; new interface definitions may be added.
· valid_capability_types: if valid_capability_types is defined in the parent type, each element in this list must either be in the parent type list or derived from an element in the parent type list; if valid_target_types is not defined in the parent type then no restrictions are applied.
· valid_target_node_types: same derivation rules as for valid_capability_types
· valid_source_node_types: same derivation rules as for valid_capability_types
mycompanytypes.myrelationships.AppDependency: derived_from: tosca.relationships.DependsOn valid_capability_types: [ mycompanytypes.mycapabilities.SomeAppCapability ] |
A Relationship Template specifies the occurrence of a manageable relationship between node templates as part of an application’s topology model that is defined in a TOSCA Service Template. A Relationship template is an instance of a specified Relationship Type and can provide customized properties, or operations that complement and change the defaults provided by its Relationship Type and its implementations.
Relations between Node Templates can be defined either using Relationship Templates or Requirements and Capability definitions within Node Types. Use of Relationship Templates decouples relationship definitions from Node Type definitions, allowing Node Type definitions to be more “generic” for use in a wider set of service templates which have varying relation definition requirements. The Relationship Templates are local within a service template and so have a limited scope. Requirements and Capabilities defined in Node Types have a wider scope, exposed within any service template which contains a Node Template of the Node Type.
Note that using the relationship templates is underspecified currently and can be used only as a further template for relationships in requirements definition. This topic needs further work.
The following is the list of recognized keynames for a TOSCA Relationship Template definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory name of the Relationship Type the Relationship Template is based upon. |
|
description |
no |
An optional description for the Relationship Template. |
|
metadata |
no |
Defines a section used to declare additional metadata information. |
|
properties |
no |
map of |
An optional map of property assignments for the Relationship Template. |
attributes |
no |
map of |
An optional map of attribute assignments for the Relationship Template. |
interfaces |
no |
map of |
An optional map of interface assignments for the relationship template. |
copy |
no |
The optional (symbolic) name of another relationship template to copy into (all keynames and values) and use as a basis for this relationship template. |
<relationship_template_name>: type: <relationship_type_name> description: <relationship_type_description> metadata: properties: attributes: interfaces: copy: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· relationship_template_name: represents the mandatory symbolic name of the Relationship Template being declared.
· relationship_type_name: represents the name of the Relationship Type the Relationship Template is based upon.
· relationship_template_description: represents the optional description string for the Relationship Template.
· property_assignments: represents the optional map of property assignments for the Relationship Template that provide values for properties defined in its declared Relationship Type.
· attribute_assignments: represents the optional map of attribute assignments for the Relationship Template that provide values for attributes defined in its declared Relationship Type.
· interface_assignments: represents the optional map of interface assignments for the Relationship Template for interface definitions provided by its declared Relationship Type.
· source_relationship_template_name: represents the optional (symbolic) name of another relationship template to copy into (all keynames and values) and use as a basis for this relationship template.
· The source relationship template provided as a value on the copy keyname MUST NOT itself use the copy keyname (i.e., it must itself be a complete relationship template description and not copied from another relationship template).
relationship_templates: storage_attachment: type: AttachesTo properties: location: /my_mount_point |
A Capability Type is a reusable entity that describes a kind of capability that a Node Type can declare to expose. Requirements (implicit or explicit) that are declared as part of one node can be matched to (i.e., fulfilled by) the Capabilities declared by another node.
The Capability Type is a TOSCA type entity and has the common keynames listed in Section 4.2.5.2 Common keynames in type definitions. In addition, the Capability Type has the following recognized keynames:
Keyname |
Mandatory |
Type |
Description |
properties |
no |
map of |
An optional map of property definitions for the Capability Type. |
attributes |
no |
map of |
An optional map of attribute definitions for the Capability Type. |
valid_source_node_types |
no |
list of string |
An optional list of one or more valid names of Node Types that are supported as valid sources of any relationship established to the declared Capability Type. If undefined, all Node Types are valid sources. |
valid_relationship_types |
no |
list of string |
An optional list of one or more valid names of Relationship Types that are supported as valid types of any relationship established to the declared Capability Type. If undefined, all Relationship Types are valid. |
Capability Types have following grammar:
derived_from: <parent_capability_type_name> version: <version_number> description: <capability_description> properties: attributes: valid_source_node_types: [ <node_type_names> ] valid_relationship_types: [ <relationship_type_names> ] |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· capability_type_name: represents the mandatory name of the Capability Type being declared as a string.
· parent_capability_type_name: represents the name of the Capability Type this Capability Type definition derives from (i.e., its “parent” type).
· version_number: represents the optional TOSCA version number for the Capability Type.
· capability_description: represents the optional description string for the Capability Type.
· property_definitions: represents the optional map of property definitions for the Capability Type.
· attribute_definitions: represents the optional map of attribute definitions for the Capability Type.
· node_type_names: represents the optional list of one or more names of Node Types that the Capability Type supports as valid sources for a successful relationship to be established to a capability of this Capability Type; if undefined, the valid source types are not restricted at all (i.e. all Node Types are valid).
· relationship_type_names: represents the optional list of one or more names of Relationship Types that the Capability Type supports as valid types for a successful relationship to be established to a capability of this Capability Type; if undefined, the valid types are not restricted at all (i.e. all Relationship Types are valid).
During Capability Type derivation the keyname definitions follow these rules:
· properties: existing property definitions may be refined; new property definitions may be added.
· attributes: existing attribute definitions may be refined; new attribute definitions may be added.
· valid_source_node_types: if valid_source_types is defined in the parent type, each element in this list must either be in the parent type list or derived from an element in the parent type list; if valid_source_types is not defined in the parent type then no restrictions are applied.
· valid_relationship_types: same derivations rules as for valid_source_node_types.
mycompany.mytypes.myapplication.MyFeature: derived_from: tosca.capabilities.Root description: a custom feature of my company’s application properties: my_feature_setting: type: string my_feature_value: type: integer |
A Capability definition defines a typed set of data that a node can expose and is used to describe a relevant feature of the component described by the node. A Capability is defined part of a Node Type definition and may be refined during Node Type derivation.
The following is the list of recognized keynames for a TOSCA capability definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory name of the Capability Type this capability definition is based upon. |
|
description |
no |
The optional description of the Capability definition. |
|
properties |
no |
map of |
An optional map of property refinements for the Capability definition. The referred properties must have been defined in the Capability Type definition referred by the type keyword. New properties may not be added. |
attributes |
no |
map of |
An optional map of attribute refinements for the Capability definition. The referred attributes must have been defined in the Capability Type definition referred by the type keyword. New attributes may not be added. |
valid_source_node_types |
no |
list of string |
An optional list of one or more valid names of Node Types that are supported as valid sources of any relationship established to the declared Capability Type. If undefined, all node types are valid sources. If valid_source_node_types is defined in the Capability Type, each element in this list must either be or derived from an element in the list defined in the type. |
valid_relationship_types |
no |
list of string |
An optional list of one or more valid names of Relationship Types that are supported as valid types of any relationship established to the declared Capability Type. If undefined, all Relationship Types are valid. If valid_relationship_types is defined in the Capability Type, each element in this list must either be or derived from an element in the list defined in the type. |
Capability definitions have one of the following grammars:
The following single-line grammar may be used when only the capability type needs to be declared, without further refinement of the definitions in the capability type:
The following multi-line grammar may be used when additional information on the capability definition is needed:
type: <capability_type> description: <capability_description> properties: attributes: valid_source_node_types: [ <node_type_names> ] valid_relationship_types: [ <relationship_type_names> ] |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· capability_definition_name: represents the symbolic name of the capability as a string.
· capability_type: represents the mandatory name of a capability type the capability definition is based upon.
· capability_description: represents the optional description of the capability definition.
· property_refinements: represents the optional map of property definitions refinements for properties already defined in the capability type; new properties may not be added.
· attribute_refinements: represents the optional map of attribute definitions refinements for attributes already defined in the capability type; new attributes may not be added.
· node_type_names: represents the optional list of one or more names of node types that the capability definition supports as valid sources for a successful relationship to be established to said capability
· if valid_source_node_types is defined in the capability type, each element in this list MUST either be in that list or derived from an element in that list; if valid_source_types is not defined in the capability type then no restrictions are applied.
· relationship_type_names: represents the optional list of one or more names of relationship types that the capability definition supports as valid type for a successful relationship to be established to said capability
· if valid_relationship_types is defined in the capability type, each element in this list MUST either be in that list or derived from an element in that list; if valid_source_types is not defined in the capability type then no restrictions are applied.
A capability definition within a node type uses the following definition refinement rules when the containing node type is derived:
· type: must be derived from (or the same as) the type in the capability definition in the parent node type definition.
· description: a new definition is unrestricted and will overwrite the one inherited from the capability definition in the parent node type definition.
· properties: not applicable to the definitions in the parent node type but to the definitions in the capability type referred by the type keyname (see grammar above for the rules).
· attributes: not applicable to the definitions in the parent node type but to the definitions in the capability type referred by the type keyname (see grammar above for the rules).
· valid_source_node_types: not applicable to the definitions in the parent node type but to the definitions in the capability type referred by the type keyname (see grammar above for the rules).
· valid_relationship_types: not applicable to the definitions in the parent node type but to the definitions in the capability type referred by the type keyname (see grammar above for the rules).
The following examples show capability definitions in both simple and full forms:
# Simple notation, no properties need to be refined some_capability: mytypes.mycapabilities.MyCapabilityTypeName |
# Full notation, refining properties some_capability: type: mytypes.mycapabilities.MyCapabilityTypeName properties: limit: default: 100 |
· Capability symbolic names SHALL be unique; it is an error if a capability name is found to occur more than once.
· The occurrences keyname is deprecated in TOSCA 2.0. By default, the number of “occurrences” is UNBOUNDED, i.e. any number of relationships can be created with a certain capability as a target. To constrain the creation of a relationship to a target capability, the new “allocation” keyname is used within a requirement assignment.
A capability assignment allows node template authors to assign values to properties and attributes for a capability definition that is part of the node templates’ respective type definition, and also to set the capability occurrences.
The following is the list of recognized keynames for a TOSCA capability assignment:
Keyname |
Mandatory |
Type |
Description |
|
properties |
no |
map of |
An optional map of property assignments for the Capability definition. |
|
attributes |
no |
map of |
An optional map of attribute assignments for the Capability definition. |
|
directives |
no
default: [internal, external] |
list of string
valid string values: “internal”, “external” |
Describes if the fulfillment of this capability assignment should use relationships with source nodes created within this template (“internal”) or should use source nodes created outside this template as available to the TOSCA environment ("external”) or if it should use a combination of the above. If so, the order of the strings in the list defines which scope should be attempted first. If no scope is defined, the default value is [internal, external]. If no directives are defined, the default value is left to the particular implementation. |
|
Capability assignments have one of the following grammars:
properties: attributes: directives: <directives_list> |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· capability_definition_name: represents the symbolic name of the capability as a string.
· property_assignments: represents the optional map of property assignments that provide values for properties defined in the Capability definition.
· attribute_assignments: represents the optional map of attribute assignments that provide values for attributes defined in the Capability definition.
· directives_list: represents the optional list of strings that defines directives for this capability:
· valid values for the strings:
· “internal” – relationships to this capability can be created from source nodes created within this template.
· “external” – relationships to this capability can be created from source nodes created outside this template as available to the TOSCA environment.
· the order of the strings in the list defines which scope should be attempted first when fulfilling the assignment.
· If no directives are defined, the default value is left to the particular implementation.
The following example shows a capability assignment:
node_templates: some_node_template: capabilities: some_capability: properties: limit: 100 |
· The occurrences keyname is deprecated in TOSCA 2.0. By default, the number of “occurrences” is UNBOUNDED, i.e. any number of relationships can be created with a certain capability as a target. To constrain the creation of a relationship to a target capability, the new “allocation” keyname is used within a requirement assignment.
Requirement types are not defined in TOSCA. TOSCA seeks to simplify the modeling by not declaring specific Requirement Types with nodes declaring their features sets using TOSCA Capability Types. So, it suffices that capabilities are advertised a-priory by Capability Types, while requirement definitions can be directly created during Node Type design.
The Requirement definition describes a requirement (dependency) of a TOSCA node which needs to be fulfilled by a matching Capability definition declared by another TOSCA node. A Requirement is defined as part of a Node Type definition and may be refined during Node Type derivation.
The following is the list of recognized keynames for a TOSCA requirement definition:
Keyname |
Mandatory |
Type |
Description |
description |
no |
The optional description of the Requirement definition. |
|
capability |
yes |
The mandatory keyname used to provide either the: · symbolic name of a Capability definition within a target Node Type that can fulfill the requirement. · name of a Capability Type that the TOSCA orchestrator will use to select a type-compatible target node to fulfill the requirement at runtime. |
|
node |
conditional |
The optional keyname used to provide the name of a valid Node Type that contains the capability definition that can be used to fulfill the requirement. If a symbolic name of a Capability definition has been used for the capability keyname, then the node keyname is mandatory. |
|
relationship |
conditional |
The optional keyname used to provide the name of a valid Relationship Type to construct a relationship when fulfilling the requirement. The relationship definition is mandatory either in the requirement definition of in the requirement assignment. |
|
node_filter |
no |
The optional filter definition that TOSCA orchestrators will use to select a type-compatible target node that can fulfill the associated abstract requirement at runtime. |
|
count_range |
no |
The optional minimum required and maximum allowed number of relationships created by the requirement. If this key is not specified, the implied default of [0, UNBOUNDED] will be used. Note: the keyword UNBOUNDED is also supported to represent any positive integer. |
The Requirement definition contains the Relationship Type information needed by TOSCA Orchestrators to construct relationships to other TOSCA nodes with matching capabilities; however, it is sometimes recognized that additional parameters may need to be passed to the relationship (perhaps for configuration). In these cases, additional grammar is provided so that the requirement definition may declare interface refinements (e.g. changing the implementation definition or declaring additional parameter definitions to be used as inputs/outputs).
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The optional keyname used to provide the name of the Relationship Type as part of the relationship keyname definition. |
|
interfaces |
no |
map of interface refinements |
The optional keyname used to reference declared interface definitions on the corresponding Relationship Type for refinement. |
Requirement definitions have one of the following grammars:
<requirement_definition_name>: description: <requirement_description> capability: <capability_symbolic_name> | <capability_type_name> node: <node_type_name> relationship: <relationship_type_name> node_filter: <node_filter_definition> count_range: [ <min_count>, <max_count> ] |
The following additional multi-line grammar is provided for the relationship keyname in order to declare new parameter definitions for inputs/outputs of known Interface definitions of the declared Relationship Type.
<requirement_definition_name>: # Other keynames omitted for brevity relationship: type: <relationship_type_name> interfaces: <interface_refinements> |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· requirement_definition_name: represents the mandatory symbolic name of the requirement definition as a string.
· requirement_description: represents the optional description of the requirement definition.
· capability_symbolic_name: represents the mandatory symbolic name of the Capability definition within the target Node Type.
· capability_type_name: represents the mandatory name of a Capability Type that can be used to fulfill the requirement.
· node_type_name: represents the name of a Node Type that contains either the Capability Type or the Capability definition the requirement can be fulfilled by; the node_type_name is mandatory if the capability_symbolic_name was used, and is optional if the capability_type_name was used.
· relationship_type_name: represents the optional name of a Relationship Type to be used to construct a relationship between this requirement definition (i.e. in the source node) to a matching capability definition (in a target node).
· node_filter_definition: represents the optional node filter TOSCA orchestrators will use to fulfill the requirement when selecting a target node, or to verify that the specified node template fulfills the requirement (if a node template was specified during requirement assignment).
· min_count, max_count: represents the optional range between a minimum required and maximum allowed count of the requirement
· this range constrains how many relationships from this requirement towards target capabilities (in target nodes) are created, and that number MUST be within the range specified here.
· by default (i.e. if count_range is undefined here), a requirement shall form exactly one relationship ( [1, 1] i.e. allowed at least one, and at most one).
· interface_refinements: represents refinements for one or more already declared interface definitions in the Relationship Type (as declared on the type keyname)
· allowing for the declaration of new parameter definitions for these interfaces or for specific operation or notification definitions of these interfaces or for the change of the description or implementation definitions.
A requirement definition within a node type uses the following definition refinement rules when the containing node type is derived:
· description: a new definition is unrestricted and will overwrite the one inherited from the requirement definition in the parent node type definition.
· capability: the type of the capability must be derived from (or the same as) the capability type in the requirement definition in the parent node type definition.
· if the capability was specified using the symbolic name of a capability definition in the target node type, then the capability keyname definition MUST remain unchanged in any subsequent refinements or during assignment.
· node: must be derived from (or the same as) the node type in the requirement definition in the parent node type definition; if node is not defined in the parent type then no restrictions are applied;
· the node type specified by the node keyname must also contain a capability definition that fulfills the requirement set via the capability keyname above.
· relationship: must be derived from (or the same as) the relationship type in the requirement definition in the parent node type definition; if relationship is not defined in the parent type then no restrictions are applied.
· node_filter: a new definition is unrestricted and will be considered in addition (i.e. logical and) to the node_filter definition in the parent node type definition; further refinements may add further node filters.
· count_range: the new range MUST be within the range defined in the requirement definition in the parent node type definition.
· Requirement symbolic names SHALL be unique; it is an error if a requirement name is found to occur more than once.
· If the count_range keyname is not present, then a default declaration as follows will be assumed:
count_range: [0, UNBOUNDED]
· The requirement symbolic name is used for identification of the requirement definition only and not relied upon for establishing any relationships in the topology.
A requirement definition allows type designers to govern which types are allowed (valid) for fulfillment using three levels of specificity with only the Capability definition or Capability Type being mandatory.
4. Node Type (mandatory/optional)
5. Relationship Type (optional)
6. Capability definition or Capability Type (mandatory)
The first level allows selection, as shown in both the simple or complex grammar, simply providing the node’s type using the node keyname. The second level allows specification of the relationship type to use when connecting the requirement to the capability using the relationship keyname. Finally, the specific Capability definition or Capability Type on the target node is provided using the capability keyname. Note that if a Capability definition is used, the Node Type definition is mandatory (as it refers to a Capability definition in that Node Type).
In addition to the node, relationship and capability types, a filter, with the keyname node_filter, may be provided to constrain the allowed set of potential target nodes based upon their properties and their capabilities’ properties. This allows TOSCA orchestrators to help find the “best fit” when selecting among multiple potential target nodes for the expressed requirements. Also, if a Node Template was specified during requirement assignment it allows TOSCA orchestrators to verify that the specified node template fulfills the requirement.
A Requirement assignment allows Node Template authors to provide assignments for the corresponding Requirement definition (i.e. having the same symbolic name) in the Node Type definition.
A Requirement assignment provides either names of Node Templates or selection criteria for TOSCA orchestrators to find matching TOSCA nodes that are used to fulfill the requirement’s declared Capability Type and/or Node Type. A Requirement assignment also provides either names of Relationship Templates (to use) or the name of Relationship Types (to create relationships) for relating the source node (containing the Requirement) to the target node (containing the Capability).
Note that several Requirement assignments in the Node Template definition can have the same symbolic name, each referring to different counts of the Requirement definition. To how many counts a particular assignment allows is set via the count_range keyname. Nevertheless, the sum of the count values for all of the Requirement assignments with the same symbolic name MUST be within the range of count_range specified by the corresponding Requirement definition.
The following is the list of recognized keynames for a TOSCA requirement assignment:
Keyname |
Mandatory |
Type |
Description |
capability |
no |
The optional keyname used to provide either the: · symbolic name of a Capability definition within a target node that can fulfill the requirement. · name of a Capability Type that the TOSCA orchestrator will use to select a type-compatible target node to fulfill the requirement at runtime. |
|
node |
no |
The optional keyname used to identify the target node of a relationship; specifically, it is used to provide either the: · name of a Node Template that can fulfill the target node requirement. · name of a Node Type that the TOSCA orchestrator will use to select a type-compatible target node to fulfill the requirement at runtime. |
|
relationship |
conditional |
The conditional keyname used to provide either the: · name of a Relationship Template to use to relate this node to the target node when fulfilling the requirement. · name of a Relationship Type that the TOSCA orchestrator will use to create a relationship to relate this node to the target node when fulfilling the requirement. · Details of a Relationship Type and its property and interface assignments that the TOSCA orchestrator will use to create a relationship to relate this node to the target node when fulfilling the requirement. The relationship definition is mandatory either in the requirement definition of in the requirement assignment. |
|
allocation |
no |
allocation block |
The optional keyname that allows the inclusion of an allocation block. The allocation block contains a map of property assignments that semantically represent “allocations” from the property with the same name in the target capability. · The allocation acts as a “capacity filter” for the target capability in the target node. When the requirement is resolved, a capability in a node is a valid target for the requirement relationship if for each property of the target capability, the sum of all existing allocations plus the current allocation is less_or_equal to the property value.
|
node_filter |
no |
The optional filter definition that TOSCA orchestrators will use to select a type-compatible target node that can fulfill the requirement at runtime. |
|
count |
no |
non-negative integer |
An optional keyname that sets the cardinality of the requirement assignment, that is how many relationships to be established from this requirement assignment specification. If not defined, the assumed count for an assignment is 1. Note that there can be multiple requirement assignments for a requirement with a specific symbolic name. · The sum of all count values of assignments for a requirement with a specific symbolic name must be within the count_range defined in the requirement definition. · Moreover, the sum of all count values of non-optional assignments for a requirement with a specific symbolic name must also be within the count_range defined in the requirement definition. |
directives |
no
|
list of string
valid string values: “internal”, “external” |
Describes if the fulfillment of this requirement assignment should use relationships with target nodes created within this template (“internal”) or should use target nodes created outside this template as available to the TOSCA environment ("external”) or if it should use a combination of the above. If so, the order of the strings in the list defines which directive should be attempted first. If no directives are defined, the default value is left to the particular implementation. |
optional |
no
default: false |
boolean |
Describes if the fulfillment of this requirement assignment is optional (true) or not (false). If not specified, the requirement assignment must be fulfilled, i.e. the default value is false. Note also, that non-optional requirements have precedence, thus during a service deployment, the optional requirements for all nodes should be resolved only after the non-optional requirements for all nodes have been resolved. |
The following is the list of recognized keynames for a TOSCA requirement assignment’s relationship keyname which is used when property assignments or interface assignments (for e.g. changing the implementation keyname or declare additional parameter definitions to be used as inputs/outputs) need to be provided:
Keyname |
Mandatory |
Type |
Description |
type |
no |
The optional keyname used to provide the name of the Relationship Type for the Requirement assignment’s relationship. |
|
properties |
no |
map of |
An optional keyname providing property assignments for the relationship. |
interfaces |
no |
map of |
The optional keyname providing Interface assignments for the corresponding Interface definitions in the Relationship Type. |
Requirement assignments have one of the following grammars:
The following single-line grammar may be used if only a concrete Node Template for the target node needs to be declared in the requirement:
The following grammar should be used if the requirement assignment needs to provide more information than just the Node Template name:
capability: <capability_symbolic_name> | <capability_type_name> node: <node_template_name> | <node_type_name> relationship: <relationship_template_name> | <relationship_type_name> node_filter: <node_filter_definition> count: <count_value> directives: <directives_list> optional: <is_optional> |
The following additional multi-line grammar is provided for the relationship keyname in order to provide new Property assignments and Interface assignments for the created relationship of the declared Relationship.
# Other keynames omitted for brevity relationship: type: <relationship_template_name> | <relationship_type_name> properties: <property_assignments> interfaces: <interface_assignments> |
The following additional multi-line grammar is provided for capacity allocation in the target capability. The property assignments under the allocation keyname represent “allocations” from the property with the same name in the target capability.
· The sum of all the allocations for all requirements assignments for a property in a target capability cannot exceed the value of that property.
· This means that during the deployment time of a certain service template – as a certain requirement assignment is resolved – a capability in a node is a valid target if
· for each property of the target capability
· the sum of all existing allocations plus the current allocation is less_or_equal to the property value
· Of course, allocations can be defined only for integer, float, or scalar property types.
<requirement_name>: # Other keynames omitted for brevity allocation: properties: <allocation_property_assignments> |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· requirement_name: represents the symbolic name of a requirement assignment as a string.
· capability_symbolic_name: represents the optional name of the Capability definition within the target Node Type or Node Template;
· if the capability in the Requirement definition was specified using the symbolic name of a capability definition in a target node type, then the capability keyname definition
· MUST remain unchanged in any subsequent refinements or during assignment.
· if the capability in the Requirement definition was specified using the name of a Capability Type, then the Capability definition referred here by the capability_symbolic_name must be of a type that is the same as or derived from the said Capability Type in the Requirement definition.
· capability_type_name: represents the optional name of a Capability Type definition within the target Node Type or Node Template this requirement needs to form a relationship with;
· may not be used if the capability in the Requirement definition was specified using the symbolic name of a capability definition in a target node type.
· otherwise the capability_type_name must be of a type that is the same as or derived from the type defined by the capability keyname in the Requirement definition.
· node_template_name: represents the optional name of a Node Template that contains the capability this requirement will be fulfilled by;
· in addition, the Node Type of the Node Template must be of a type that is the same as or derived from the type defined by the node keyname (if the node keyname is defined) in the Requirement definition,
· in addition, the Node Template must fulfill the node filter requirements of the node_filter (if a node_filter is defined) in the Requirement definition.
· node_type_name: represents the optional name of a Node Type that contains the capability this Requirement will be fulfilled by;
· in addition, the node_type_name must be of a type that is the same as or derived from the type defined by the node keyname (if the node keyname is defined) in the Requirement definition.
· relationship_template_name: represents the optional name of a Relationship Template to be used when relating the Requirement to the Capability in the target node.
· in addition, the Relationship Type of the Relationship Template must be of a type that is the same as or derived from the type defined by the relationship keyname (if the relationship keyname is defined) in the Requirement definition.
· relationship_type_name: represents the optional name of a Relationship Type that is compatible with the Capability Type in the target node; the TOSCA orchestrator will create a relationship of the Relationship Type when relating the Requirement to the Capability in the target node.
· in addition, the relationship_type_name must be of a type that is the same as or derived from the type defined by the relationship keyname (if the relationship keyname is defined) in the Requirement definition.
· property_assignments: within the relationship declaration, it represents the optional map of property assignments for the declared relationship.
· interface_assignments: represents the optional map of interface assignments for the declared relationship used to provide parameter assignments on inputs and outputs of interfaces, operations and notifications or changing the implementation definition.
· allocation_property_assignments: within the allocation declaration, it represents the optional map of property assignments that semantically represent “allocations” from the property with the same name in the target capability. Syntactically their form is the same as for a normal property assignments.
· The allocation acts as a “capacity filter” for the target capability in the target node. When the requirement is resolved, a capability in a node is a valid target for the requirement relationship if for each property of the target capability, the sum of all existing allocations plus the current allocation is less_or_equal to the property value.
· Intuitively, the sum of “allocations” from all the incoming relationships for a certain capability property cannot exceed the value of the property.
· If the “allocation” refers (via its name) to a property that does not exist in a capability, then that capability cannot be a valid target.
· Of course, allocations can be defined only for integer, float, or scalar property types.
· node_filter_definition: represents the optional node filter TOSCA orchestrators will use to fulfill the requirement for selecting a target node; if a node template was specified during requirement assignment, the TOSCA orchestrator verifies that the specified node template fulfills the node filter.
· this node_filter does not replace the node_filter definition in the Requirement definition, it is applied in addition to that.
· count_value: represents the optional cardinality of this requirement assignment, that is how many relationships are to be established from this requirement assignment specification.
· If count is not defined, the assumed count_value for an assignment is 1.
· Note that there can be multiple requirement assignments for a requirement with a specific symbolic name.
· The sum of all count values of assignments for a requirement with a specific symbolic name must be within the count_range defined in the requirement definition.
· Moreover, the sum of all count values of non-optional assignments for a requirement with a specific symbolic name must also be within the count_range defined in the requirement definition.
· directives: represents the optional list of strings that defines directives for this requirement assignment:
· valid values for the strings:
· “internal” – relationship created by this requirement assignment use target nodes created within this template.
· “external” – relationship created by this requirement assignment use target nodes created outside this template as available to the TOSCA environment.
· the order of the strings in the list defines which directive should be attempted first when fulfilling the assignment.
· If no directives are defined, the default value is left to the particular implementation.
· is_optional: represents the optional boolean value specifying if this requirement assignment is optional or not.
· If is_optional is false, the assignment MUST be fulfilled.
· If is_optional is true, the assignment SHOULD be fulfilled, but if not possible the service deployment is still considered valid.
· The default value for is_optional is false.
· If no explicit requirement assignment for a requirement with symbolic name is defined, a default requirement assignment with keynames: capability, node, relationship, node_filter having the same values as in the requirement definition in the corresponding node type is assumed.
· Additionally, the count_value is assumed to be equal to the min_count value of the requirement definition in the corresponding node type.
· For all explicit requirement assignments with the same symbolic name:
· the sum of the count_value must be within the count_range specified in the corresponding requirement definition.
· the sum of the count_value for all non-optional requirements assignments must be within the count_range specified in the corresponding requirement definition.
· Non-optional requirements have precedence, thus during a service deployment, the optional requirements for all nodes should be resolved only after the non-optional requirements for all nodes have been resolved.
Examples of uses for the extended requirement assignment grammar include:
· The need to allow runtime selection of the target node a Node Type rather than a Node Template. This may include use of the node_filter keyname to provide node and capability filtering information to find the “best match” of a node at runtime.
· The need to further specify the Relationship Template or Relationship Type to use when relating the source node’s requirement to the target node’s capability.
· The need to further specify the capability (symbolic) name or Capability Type in the target node to form a relationship between.
· The need to specify the number of counts the requirement assigns (when greater than 1).
A web application node template named ‘my_application_node_template’ of type WebApplication declares a requirement named ‘host’ that needs to be fulfilled by any node that derives from the node type WebServer.
# Example of a requirement fulfilled by a specific web server node template node_templates: my_application_node_template: type: tosca.nodes.WebApplication ... requirements: - host: node: tosca.nodes.WebServer |
In this case, the node template’s type is WebApplication which already declares the Relationship Type HostedOn to use to relate to the target node and the Capability Type of Container to be the specific target of the requirement in the target node.
This example is similar to the previous example; however, the requirement named ‘database’ describes a requirement for a connection to a database endpoint (Endpoint.Database) Capability Type in a node template (my_database). However, the connection requires a custom Relationship Type (my.types.CustomDbConnection’) declared on the keyname ‘relationship’.
# Example of a (database) requirement that is fulfilled by a node template named # “my_database”, but also requires a custom database connection relationship my_application_node_template: requirements: - database: node: my_database capability: Endpoint.Database relationship: my.types.CustomDbConnection |
This example shows how to extend an abstract ‘host’ requirement for a Compute node with a filter definition that further constrains TOSCA orchestrators to include additional properties and capabilities on the target node when fulfilling the requirement.
node_templates: mysql: type: tosca.nodes.DBMS.MySQL properties: # omitted here for brevity requirements: - host: node: tosca.nodes.Compute node_filter: capabilities: - host: properties: - num_cpus: { in_range: [ 1, 4 ] } - mem_size: { greater_or_equal: 512 MB } - os: properties: - architecture: { equal: x86_64 } - type: { equal: linux } - distribution: { equal: ubuntu } - mytypes.capabilities.compute.encryption: properties: - algorithm: { equal: aes } - keylength: { valid_values: [ 128, 256 ] } |
This example shows how the assignments can look if the Requirement definition has the count_range different from the default [1,1]. In this case the redundant_database requirement has count_range: [2,2]. The Requirement definition is not presented here for brevity. In the Requirement assignment we use the short notation. Note that the count keyname for each assignment is not declared (i.e. the default value of 1 is used) and that the sum of the count values of both assignments is 2 which is in the range of [2,2] as specified in the Requirement definition.
# Example of a (redundant_database) requirement that is fulfilled by # two node templates named “database1” and “database1 my_critical_application_node_template: requirements: - redundant_database: database1 - redundant_database: database2 |
This example shows how the assignment can look if the requirement is assuming a “capacity allocation” on the properties of the target capability (in this case a capability of type “tosca.capabilities.Compute”). When this requirement is resolved, a node is a valid target and a relationship is created only if both the capacity allocations for num_cpu and mem_size are fulfilled, that is the sum of the capacity allocations from all established relationships + current allocation is less or equal to the value of each respective property in the target capability.
So assuming that num_cpu property in the target capability of a candidate node has value 4 and the sum of capacity allocations of the other resolved requirements to that capability for num_cpu is 1 then then there is enough “remaining capacity” (4 – 1 = 3) to fulfill the current allocation (2), and a relationship to that node is established. Another node with num_cpu with value 2 could not be a valid target since 1 (existing) + 2 (current) = 3, and that is larger than the property value which is 2. Of course, similar calculations must be done for the mem_size allocation.
# Example of a (redundant_database) requirement that is fulfilled by # two node templates named “database1” and “database1 my_critical_application_node_template: requirements: - host: node: tosca.nodes.Compute allocation: properties: num_cpu: 2 mem_size: 128 MB |
Node filters are defines using condition clauses as shown in the following grammar:
node_filter: <condition_clause> |
In the above grammar, the condition_clause represents a Boolean expression that will be used to select (filter) TOSCA nodes that are valid candidates for fulfilling the requirement that defines the node filter. TOSCA orchestrators use node filters are follows:
· Orchestrators select an initial set of target node candidates based on the target capability type and/or the target node type specified in the requirement definition.
· A node in this initial set is a valid target node candidate if—when that node is used as the target node for the requirement—the node filter condition clause evaluates to True.
· Note that the context within which the node filter must be evaluated is the relationship that is established to the target node as a result of fulfilling the requirement. Specifically, this means that the SELF keyword in any TOSCA Path expressions refer to that relationship.
The following example is a filter that will be used to select a Compute node based upon the values of its defined capabilities. Specifically, this filter will select Compute nodes that support a specific range of CPUs (i.e., num_cpus value between 1 and 4) and memory size (i.e., mem_size of 2 or greater) from its declared “host” capability.
my_node_template: # other details omitted for brevity requirements: - host: node_filter: $and: - $in_range: - $get_property: [ SELF, CAPABILITY, num_cpus ] - [ 1, 4 ] - $greater_or_equal: - $get_property: [ SELF, CAPABILITY, mem_size ] - 512 MB |
An Interface Type is a reusable entity that describes a set of operations that can be used to interact with or to manage a node or relationship in a TOSCA topology.
The Interface Type is a TOSCA type entity and has the common keynames listed in Section 4.2.5.2 Common keynames in type definitions. In addition, the Interface Type has the following recognized keynames:
Keyname |
Mandatory |
Type |
Description |
inputs |
no |
map of parameter definitions |
The optional map of input parameter definitions available to all operations defined for this interface. |
operations |
no |
map of operation definitions |
The optional map of operations defined for this interface. |
notifications |
no |
map of notification definitions |
The optional map of notifications defined for this interface. |
Interface Types have following grammar:
derived_from: <parent_interface_type_name> version: <version_number> metadata: description: <interface_description> inputs: operations: notifications: <Error! Reference source not found.Error! Reference source not found.notification_definitions> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· interface_type_name: represents the mandatory name of the interface as a string.
· parent_interface_type_name: represents the name of the Interface Type this Interface Type definition derives from (i.e. its “parent” type).
· version_number: represents the optional TOSCA version number for the Interface Type.
· interface_description: represents the optional description for the Interface Type.
· parameter_definitions: represents the optional map of parameter definitions which the TOSCA orchestrator will make available (i.e., or pass) to all implementation artifacts for operations declared on the interface during their execution.
· operation_definitions: represents the optional map of one or more operation definitions.
· notification_definitions: represents the optional map of one or more notification definitions.
During Interface Type derivation the keyname definitions follow these rules:
· inputs: existing parameter definitions may be refined; new parameter definitions may be added.
· operations: existing operation definitions may be refined; new operation definitions may be added.
· notifications: existing notification definitions may be refined; new notification definitions may be added.
The following example shows a custom interface used to define multiple configure operations.
mycompany.mytypes.myinterfaces.MyConfigure: derived_from: tosca.interfaces.relationship.Root description: My custom configure Interface Type inputs: mode: type: string operations: pre_configure_service: description: pre-configure operation for my service post_configure_service: description: post-configure operation for my service |
· Interface Types MUST NOT include any implementations for defined operations or notifications; that is, the implementation keyname is invalid in this context.
An Interface definition defines an interface (containing operations and notifications definitions) that can be associated with (i.e. defined within) a Node or Relationship Type definition (including Interface definitions in Requirements definitions). An Interface definition may be refined in subsequent Node or Relationship Type derivations.
The following is the list of recognized keynames for a TOSCA interface definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
string |
The mandatory name of the Interface Type this interface definition is based upon. |
description |
no |
The optional description for this interface definition. |
|
inputs |
no |
map of |
The optional map of input parameter refinements and new input parameter definitions available to all operations defined for this interface (the input parameters to be refined have been defined in the Interface Type definition). |
operations |
no |
map of operation refinements |
The optional map of operations refinements for this interface. The referred operations must have been defined in the Interface Type definition. |
notifications |
no |
map of notification refinements |
The optional map of notifications refinements for this interface. The referred operations must have been defined in the Interface Type definition. |
Interface definitions in Node or Relationship Type definitions have the following grammar:
type: <interface_type_name> description: <interface_description> inputs: <parameter_definitions_and_refinements> operations: notifications: <Error! Reference source not found.Error! Reference source not found.notification_refinements> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· interface_definition_name: represents the mandatory symbolic name of the interface as a string.
· interface_type_name: represents the mandatory name of the Interface Type for the interface definition.
· interface_description: represents the optional description string for the interface.
· parameter_definitions_and_refinements: represents the optional map of input parameters which the TOSCA orchestrator will make available (i.e. pass) to all defined operations. This means these parameters and their values will be accessible to the implementation artifacts (e.g., scripts) associated to each operation during their execution
· the map represents a mix of parameter refinements (for parameters already defined in the Interface Type) and new parameter definitions.
· with the new parameter definitions, we can flexibly add new parameters when changing the implementation of operations and notifications during refinements or assignments.
· operation_refinements: represents the optional map of operation definition refinements for this interface; the referred operations must have been previously defined in the Interface Type.
· notification_refinements: represents the optional map of notification definition refinements for this interface; the referred notifications must have been previously defined in the Interface Type.
An interface definition within a node or relationship type (including interface definitions in requirements definitions) uses the following definition refinement rules when the containing entity type is derived:
· type: must be derived from (or the same as) the type in the interface definition in the parent entity type definition.
· description: a new definition is unrestricted and will overwrite the one inherited from the interface definition in the parent entity type definition.
· inputs: not applicable to the definitions in the parent entity type but to the definitions in the interface type referred by the type keyname (see grammar above for the rules).
· operations: not applicable to the definitions in the parent entity type but to the definitions in the interface type referred by the type keyname (see grammar above for the rules).
· notifications: not applicable to the definitions in the parent entity type but to the definitions in the interface type referred by the type keyname (see grammar above for the rules).
An Interface assignment is used to specify assignments for the inputs, operations and notifications defined in the Interface. Interface assignments may be used within a Node or Relationship Template definition (including when Interface assignments are referenced as part of a Requirement assignment in a Node Template).
The following is the list of recognized keynames for a TOSCA interface definition:
Keyname |
Mandatory |
Type |
Description |
inputs |
no |
map of parameter value assignments |
The optional map of input parameter assignments. Template authors MAY provide parameter assignments for interface inputs that are not defined in their corresponding Interface Type. |
operations |
no |
map of operation assignments |
The optional map of operations assignments specified for this interface. |
notifications |
no |
map of notification assignments |
The optional map of notifications assignments specified for this interface. |
Interface assignments have the following grammar:
inputs: operations: notifications: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· interface_definition_name: represents the mandatory symbolic name of the interface as a string.
· parameter_value_assignments: represents the optional map of parameter value assignments for passing input parameter values to all interface operations
· template authors MAY provide new parameter assignments for interface inputs that are not defined in the Interface definition.
· operation_assignments: represents the optional map of operation assignments for operations defined in the Interface definition.
· notification_assignments: represents the optional map of notification assignments for notifications defined in the Interface definition.
An operation definition defines a function or procedure to which an operation implementation can be bound.
A new operation definition may be declared only inside interface type definitions (this is the only place where new operations can be defined). In interface type, node type, or relationship type definitions (including operation definitions as part of a requirement definition) we may further refine operations already defined in an interface type.
An operation definition or refinement inside an interface type definition may not contain an operation implementation definition and it may not contain an attribute mapping as part of its output definition (as both these keynames are node/relationship specific).
The following is the list of recognized keynames for a TOSCA operation definition (including definition refinement)
Keyname |
Mandatory |
Type |
Description |
description |
no |
The optional description string for the associated operation. |
|
implementation |
no |
The optional definition of the operation implementation. May not be used in an interface type definition (i.e. where an operation is initially defined), but only during refinements. |
|
inputs |
no |
map of |
The optional map of parameter definitions for operation input values. |
outputs |
no |
map of |
The optional map of parameter definitions for operation output values. Only as part of node and relationship type definitions, the output definitions may include mappings onto attributes of the node or relationship type that contains the definition. |
Operation definitions have the following grammar:
The following single-line grammar may be used when the operation’s implementation definition is the only keyname that is needed, and when the operation implementation definition itself can be specified using a single line grammar:
The following multi-line grammar may be used when additional information about the operation is needed:
description: <operation_description> implementation: <operation_implementation_definition> inputs: outputs: |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· operation_name: represents the mandatory symbolic name of the operation as a string.
· operation_description: represents the optional description string for the operation.
· operation_implementation_definition: represents the optional specification of the operation’s implementation).
· parameter_definitions: represents the optional map of parameter definitions which the TOSCA orchestrator will make available as inputs to or receive as outputs from the corresponding implementation artifact during its execution.
An operation definition within an interface, node, or relationship type (including interface definitions in requirements definitions) uses the following refinement rules when the containing entity type is derived:
· description: a new definition is unrestricted and will overwrite the one inherited from the operation definition in the parent entity type definition.
· implementation: a new definition is unrestricted and will overwrite the one inherited from the operation definition in the parent entity type definition.
· inputs: parameter definitions inherited from the parent entity type may be refined; new parameter definitions may be added.
· outputs: parameter definitions inherited from the parent entity type may be refined; new parameter definitions may be added.
· The definition of implementation is not allowed in interface type definitions (as a node or node type context is missing at that point). Thus, it can be part only of an operation refinement and not of the original operation definition.
· The default refinement behavior for implementations SHALL be overwrite. That is, implementation definitions in a derived type overwrite any defined in its parent type.
· Defining a fixed value for an input parameter (as part of its definition) may only use a parameter_value_expression that is meaningful in the scope of the context. For example, within the context of an Interface Type definition functions such as get_propery or get_attribute cannot be used. Within the context of Node or Relationship Type definitions, these functions may only reference properties and attributes accessible starting from SELF (i.e. accessing a node by symbolic name is not meaningful).
· Defining attribute mapping as part of the output parameter definition is not allowed in interface type definitions (i.e. as part of operation definitions). It is allowed only in node and relationship type definitions (as part of operation refinements) and has to be meaningful in the scope of the context (e.g. SELF).
· Implementation artifact file names (e.g., script filenames) may include file directory path names that are relative to the TOSCA file file itself when packaged within a TOSCA Cloud Service Archive (CSAR) file.
interfaces: Standard: start: scripts/start_server.sh |
interfaces: Configure: pre_configure_source: implementation: primary: scripts/pre_configure_source.sh dependencies: - scripts/setup.sh - binaries/library.rpm - scripts/register.py |
interfaces: Configure: pre_configure_source: implementation: primary: file: scripts/pre_configure_source.sh type: tosca.artifacts.Implementation.Bash repository: my_service_catalog dependencies: - file : scripts/setup.sh type : tosca.artifacts.Implementation.Bash repository : my_service_catalog |
An operation assignment may be used to assign values for input parameters, specify attribute mappings for output parameters, and define/redefine the implementation definition of an already defined operation in the interface definition. An operation assignment may be used inside interface assignments inside node template or relationship template definitions (this includes when operation assignments are part of a requirement assignment in a node template).
An operation assignment may add or change the implementation and description definition of the operation. Assigning a value to an input parameter that had a fixed value specified during operation definition or refinement is not allowed. Providing an attribute mapping for an output parameter that was mapped during an operation refinement is also not allowed.
Note also that in the operation assignment we can use inputs and outputs that have not been previously defined in the operation definition. This is equivalent to an ad-hoc definition of a parameter, where the type is inferred from the assigned value (for input parameters) or from the attribute to map to (for output parameters).
The following is the list of recognized keynames for an operation assignment:
Keyname |
Mandatory |
Type |
Description |
implementation |
no |
The optional definition of the operation implementation. Overrides implementation provided at operation definition. |
|
inputs |
no |
map of parameter value assignments |
The optional map of parameter value assignments for assigning values to operation inputs. |
outputs |
no |
map of parameter |
The optional map of parameter mapping assignments that specify how operation outputs are mapped onto attributes of the node or relationship that contains the operation definition. |
Operation assignments have the following grammar:
The following single-line grammar may be used when the operation’s implementation definition is the only keyname that is needed, and when the operation implementation definition itself can be specified using a single line grammar:
The following multi-line grammar may be used in Node or Relationship Template definitions when additional information about the operation is needed:
implementation: <operation_implementation_definition> inputs: outputs: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· operation_name: represents the mandatory symbolic name of the operation as a string.
· operation_implementation_definition: represents the optional specification of the operation’s implementation
· the implementation declared here overrides the implementation provided at operation definition.
· parameter_value_assignments: represents the optional map of parameter value assignments for passing input parameter values to operations.
· assignments for operation inputs that are not defined in the operation definition may be provided
· parameter_mapping_assignments: represents the optional map of parameter mapping assignments that consists of named output values returned by operation implementations (i.e. artifacts) and associated attributes into which this output value must be stored
· assignments for operation outputs that are not defined in the operation definition may be provided.
· The behavior for implementation of operations SHALL be override. That is, implementation definitions assigned in an operation assignment override any defined in the operation definition.
· Template authors MAY provide parameter assignments for operation inputs that are not defined in the operation definition.
· Template authors MAY provide attribute mappings for operation outputs that are not defined in the operation definition.
· Implementation artifact file names (e.g., script filenames) may include file directory path names that are relative to the TOSCA file file itself when packaged within a TOSCA Cloud Service Archive (CSAR) file.
TBD
A notification definition defines an asynchronous notification or incoming message that can be associated with an interface. The notification is a way for an external event to be transmitted to the TOSCA orchestrator. Values can be sent with a notification as notification outputs and we can map them to node/relationship attributes similarly to the way operation outputs are mapped to attributes. The artifact that the orchestrator is registering with in order to receive the notification is specified using the implementation keyname in a similar way to operations. As opposed to an operation definition, a notification definition does not include an inputs keyname since notifications are not invoked from the orchestrator.
When the notification is received an event is generated within the orchestrator that can be associated to triggers in policies to call other internal operations and workflows. The notification name (using the <interface_name>.<notification_name> notation) itself identifies the event type that is generated and can be textually used when defining the associated triggers.
A notification definition may be used only inside interface type definitions (this is the only place where new notifications can be defined). Inside interface type, node type, or relationship type definitions (including notifications definitions as part of a requirement definition) we may further refine a notification already defined in the interface type.
A notification definition or refinement inside an interface type definition may not contain a notification implementation definition and it may not contain an attribute mapping as part of its output definition (as both these keynames are node/relationship specific).
The following is the list of recognized keynames for a TOSCA notification definition:
Keyname |
Mandatory |
Type |
Description |
description |
no |
The optional description string for the associated notification. |
|
implementation |
no |
The optional definition of the notification implementation. |
|
outputs |
no |
map of parameter definitions |
The optional map of parameter definitions that specify notification output values. Only as part of node and relationship type definitions, the output definitions may include their mappings onto attributes of the node type or relationship type that contains the definition. |
Notification definitions have the following grammar:
The following single-line grammar may be used when the notification’s implementation definition is the only keyname that is needed and when the notification implementation definition itself can be specified using a single line grammar:
<notification_name>: <notification_implementation_definition> |
The following multi-line grammar may be used when additional information about the notification is needed:
<notification_name>: description: <notification_description> implementation: <notification_implementation_definition> outputs: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· notification_name: represents the mandatory symbolic name of the notification as a string.
· notification_description: represents the optional description string for the notification.
· notification_implementation_definition: represents the optional specification of the notification implementation (i.e. the external artifact that may send notifications)
· parameter_definitions: represents the optional map of parameter definitions for parameters that the orchestrator will receive as outputs from the corresponding implementation artifact during its execution.
A notification definition within an interface, node, or relationship type (including interface definitions in requirements definitions) uses the following refinement rules when the containing entity type is derived:
· description: a new definition is unrestricted and will overwrite the one inherited from the notification definition in the parent entity type definition.
· implementation: a new definition is unrestricted and will overwrite the one inherited from the notification definition in the parent entity type definition.
· outputs: parameter definitions inherited from the parent entity type may be refined; new parameter definitions may be added.
· The definition of implementation is not allowed in interface type definitions (as a node or node type context is missing at that point). Thus, it can be part only of a notification refinement and not of the original notification definition.
· The default sub-classing (i.e. refinement) behavior for implementations of notifications SHALL be overwrite. That is, implementation artifacts definitions in a derived type overwrite any defined in its parent type.
· Defining attribute mapping as part of the output parameter definition is not allowed in interface type definitions (i.e. as part of operation definitions). It is allowed only in node and relationship type definitions (as part of operation refinements).
· Defining a mapping in an output parameter definition may use an attribute target that is meaningful in the scope of the context. Within the context of Node or Relationship Type definitions these functions may only reference attributes starting from the same node (i.e. SELF).
· Implementation artifact file names (e.g., script filenames) may include file directory path names that are relative to the TOSCA file file itself when packaged within a TOSCA Cloud Service Archive (CSAR) file.
TBD
A notification assignment may be used to specify attribute mappings for output parameters and to define/redefine the implementation definition and description definition of an already defined notification in the interface definition. A notification assignment may be used inside interface assignments inside node or relationship template definitions (this includes when notification assignments are part of a requirement assignment in a node template).
Providing an attribute mapping for an output parameter that was mapped during a previous refinement is not allowed. Note also that in the notification assignment we can use outputs that have not been previously defined in the operation definition. This is equivalent to an ad-hoc definition of an output parameter, where the type is inferred from the attribute to map to.
The following is the list of recognized keynames for a TOSCA notification assignment:
Keyname |
Mandatory |
Type |
Description |
implementation |
no |
The optional definition of the notification implementation. Overrides implementation provided at notification definition. |
|
outputs |
no |
map of parameter |
The optional map of parameter mapping assignments that specify how notification outputs values are mapped onto attributes of the node or relationship type that contains the notification definition. |
Notification assignments have the following grammar:
The following single-line grammar may be used when the notification’s implementation definition is the only keyname that is needed, and when the notification implementation definition itself can be specified using a single line grammar:
<notification_name>: <notification_implementation_definition> |
The following multi-line grammar may be used in Node or Relationship Template definitions when additional information about the notification is needed:
implementation: <notification_implementation_definition> outputs: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· notification_name: represents the mandatory symbolic name of the notification as a string.
· notification_implementation_definition: represents the optional specification of the notification implementation (i.e. the external artifact that is may send notifications)
· the implementation declared here overrides the implementation provided at notification definition.
· parameter_mapping_assignments: represents the optional map of parameter_mapping_assignments that consists of named output values returned by operation implementations (i.e. artifacts) and associated attributes into which this output value must be stored
· assignments for notification outputs that are not defined in the operation definition may be provided.
· The behavior for implementation of notifications SHALL be override. That is, implementation definitions assigned in a notification assignment override any defined in the notification definition.
· Template authors MAY provide attribute mappings for notification outputs that are not defined in the corresponding notification definition.
· Implementation artifact file names (e.g., script filenames) may include file directory path names that are relative to the TOSCA file file itself when packaged within a TOSCA Cloud Service Archive (CSAR) file.
TBD
An operation implementation definition specifies one or more artifacts (e.g. scripts) to be used as the implementation for an operation in an interface.
A notification implementation definition specifies one or more artifacts to be used by the orchestrator to subscribe and receive a particular notification (i.e. the artifact implements the notification).
The operation implementation definition and the notification implementation definition share the same keynames and grammar, with the exception of the timeout keyname that has no meaning in the context of a notification implementation definition and should not be used in such.
The following is the list of recognized keynames for an operation implementation definition or a notification implementation definition:
Keyname |
Mandatory |
Type |
Description |
primary |
no |
The optional implementation artifact (i.e., the primary script file within a TOSCA CSAR file). |
|
dependencies |
no |
list of |
The optional list of one or more dependent or secondary implementation artifacts which are referenced by the primary implementation artifact (e.g., a library the script installs or a secondary script). |
timeout |
no |
integer |
Timeout value in seconds. Has no meaning and should not be used within a notification implementation definition. |
Operation implementation definitions and notification implementation definitions have the following grammar:
The following single-line grammar may be used when only a primary implementation artifact name is needed:
This notation can be used when the primary artifact name uniquely identifies the artifact, either because it refers to an artifact specified in the artifacts section of a type or template, or because it represents the name of a script in the CSAR file that contains the definition.
The following multi-line short-hand grammar may be used when multiple artifacts are needed, but each of the artifacts can be uniquely identified by name as before:
implementation: primary: <primary_artifact_name> dependencies: - <list_of_dependent_artifact_names> timeout: 60 |
The following multi-line grammar may be used in Node or Relationship Type or Template definitions when only a single artifact is used but additional information about the primary artifact is needed (e.g. to specify the repository from which to obtain the artifact, or to specify the artifact type when it cannot be derived from the artifact file extension):
implementation: primary: timeout: 100 |
The following multi-line grammar may be used in Node or Relationship Type or Template definitions when there are multiple artifacts that may be needed for the operation to be implemented and additional information about each of the artifacts is required:
implementation: primary: dependencies: - <list_of_dependent_artifact definitions> timeout: 120 |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· primary_artifact_name: represents the optional name (string) of an implementation artifact definition (defined elsewhere), or the direct name of an implementation artifact’s relative filename (e.g., a service template-relative, path-inclusive filename or absolute file location using a URL).
· primary_artifact_definition: represents a full inline definition of an implementation artifact.
· list_of_dependent_artifact_names: represents the optional ordered list of one or more dependent or secondary implementation artifact names (as strings) which are referenced by the primary implementation artifact. TOSCA orchestrators will copy these files to the same location as the primary artifact on the target node so as to make them accessible to the primary implementation artifact when it is executed.
· list_of_dependent_artifact_definitions: represents the ordered list of one or more inline definitions of dependent or secondary implementation artifacts. TOSCA orchestrators will copy these artifacts to the same location as the primary artifact on the target node so as to make them accessible to the primary implementation artifact when it is executed.
An Artifact Type is a reusable entity that defines the type of one or more files that are used to define implementation or deployment artifacts that are referenced by nodes or relationships.
The Artifact Type is a TOSCA type entity and has the common keynames listed in Section 4.2.5.2 Common keynames in type definitions. In addition, the Artifact Type has the following recognized keynames:
Keyname |
Mandatory |
Type |
Description |
mime_type |
no |
The optional mime type property for the Artifact Type. |
|
file_ext |
no |
list of string |
The optional file extension property for the Artifact Type. |
properties |
no |
map of |
An optional map of property definitions for the Artifact Type. |
Artifact Types have following grammar:
derived_from: <parent_artifact_type_name> version: <version_number> metadata: description: <artifact_description> mime_type: <mime_type_string> file_ext: [ <file_extensions> ] properties: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· artifact_type_name: represents the name of the Artifact Type being declared as a string.
· parent_artifact_type_name: represents the name of the Artifact Type this Artifact Type definition derives from (i.e., its “parent” type).
· version_number: represents the optional TOSCA version number for the Artifact Type.
· artifact_description: represents the optional description string for the Artifact Type.
· mime_type_string: represents the optional Multipurpose Internet Mail Extensions (MIME) standard string value that describes the file contents for this type of Artifact Type as a string.
· file_extensions: represents the optional list of one or more recognized file extensions for this type of artifact type as strings.
· property_definitions: represents the optional map of property definitions for the artifact type.
During Artifact Type derivation the keyname definitions follow these rules:
· mime_type: a new definition is unrestricted and will overwrite the one inherited from the parent type.
· file_ext: a new definition is unrestricted and will overwrite the one inherited from the parent type.
· properties: existing property definitions may be refined; new property definitions may be added.
my_artifact_type: description: Java Archive artifact type derived_from: tosca.artifact.Root mime_type: application/java-archive file_ext: [ jar ] properties: id: description: Identifier of the jar type: string required: true creator: description: Vendor of the java implementation on which the jar is based type: string required: false |
· The ‘mime_type’ keyname is meant to have values that are Apache mime types such as those defined here: http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types
Information about artifacts can be broadly classified in two categories that serve different purposes:
· Selection of artifact processor. This category includes informational elements such as artifact version, checksum, checksum algorithm etc. and s used by TOSCA Orchestrator to select the correct artifact processor for the artifact. These informational elements are captured in TOSCA as keywords for the artifact.
· Properties processed by artifact processor. Some properties are not processed by the Orchestrator but passed on to the artifact processor to assist with proper processing of the artifact. These informational elements are described through artifact properties.
An artifact definition defines a named, typed file that can be associated with Node Type or Node Template and used by orchestration engine to facilitate deployment and implementation of interface operations.
The following is the list of recognized keynames for a TOSCA artifact definition when using the extended notation:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory artifact type for the artifact definition. |
|
file |
yes |
The mandatory URI string (relative or absolute) which can be used to locate the artifact’s file. |
|
repository |
no |
The optional name of the repository definition which contains the location of the external repository that contains the artifact. The artifact is expected to be referenceable by its file URI within the repository. |
|
description |
no |
The optional description for the artifact definition. |
|
deploy_path |
no |
The file path the associated file will be deployed on within the target node’s container. |
|
artifact_version |
no |
string |
The version of this artifact. One use of this artifact_version is to declare the particular version of this artifact type, in addition to its mime_type (that is declared in the artifact type definition). Together with the mime_type it may be used to select a particular artifact processor for this artifact. For example, a python interpreter that can interpret python version 2.7.0. |
checksum |
no |
string |
The checksum used to validate the integrity of the artifact. |
checksum_algorithm |
no |
string |
Algorithm used to calculate the artifact checksum (e.g. MD5, SHA [Ref]). Shall be specified if checksum is specified for an artifact.
|
properties |
no |
map of assignments |
The optional map of property assignments associated with the artifact. |
Artifact definitions have one of the following grammars:
The following single-line grammar may be used when the artifact’s type and mime type can be inferred from the file URI:
The following multi-line grammar may be used when the artifact’s definition’s type and mime type need to be explicitly declared:
description: <artifact_description> type: <artifact_type_name> file: <artifact_file_URI> repository: <artifact_repository_name> deploy_path: <file_deployment_path> version: <artifact _version> checksum: <artifact_checksum> checksum_algorithm: <artifact_checksum_algorithm> properties: <property assignments> |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· artifact_name: represents the mandatory symbolic name of the artifact as a string.
· artifact_description: represents the optional description for the artifact.
· artifact_type_name: represents the mandatory artifact type the artifact definition is based upon.
· artifact_file_URI: represents the mandatory URI string (relative or absolute) which can be used to locate the artifact’s file.
· artifact_repository_name: represents the optional name of the repository definition to use to retrieve the associated artifact (file) from.
· file_deployement_path: represents the optional path the artifact_file_URI will be copied into within the target node’s container.
· artifact_version: represents the version of artifact
· artifact_checksum: represents the checksum of the Artifact
· artifact_checksum_algorithm:represents the algorithm for verifying the checksum. Shall be specified if checksum is specified
· properties: represents an optional map of property assignments associated with the artifact
Artifact definitions represent specific external entities. If a certain artifact definition cannot be reused as is, then it may be completely redefined.
· If an artifact is redefined, the symbolic name from the definition in the parent node type is reused, but no keyname definitions are inherited from the definition in the parent node type, and the new definition completely overwrites the definition in the parent.
· If the artifact is not redefined the complete definition is inherited from the parent node type.
The following represents an artifact definition:
my_file_artifact: ../my_apps_files/operation_artifact.txt |
The following example represents an artifact definition with property assignments:
artifacts: sw_image: description: Image for virtual machine type: tosca.artifacts.Deployment.Image.VM file: http://10.10.86.141/images/Juniper_vSRX_15.1x49_D80_preconfigured.qcow2 checksum: ba411cafee2f0f702572369da0b765e2 version: 3.2 checksum_algorithm: MD5 properties: name: vSRX container_format: BARE disk_format: QCOW2 min_disk: 1 GB size: 649 MB |
This section presents handling data in TOSCA via properties, attributes, and parameters.
The type of the values they contain can be divided into built-in primitive types, special types that are extensions of the primitive types, and collection types, as well as user-defined refinements of these and complex data types that can themselves be defined in TOSCA profiles and the TOSCA file.
Values can also be evaluated from expressions based on TOSCA functions. [See XXX]
The following table summarizes the built-in types. All of these type names are reserved and cannot be used for custom data types. Note, however, that it is possible to derive a custom data type from a primitive type in order to add validation clauses.
Primitive Types: (section 4.4.1)
· string
· integer
· float
· boolean
· bytes
· nil
Special Types: (section 4.4.2)
· range
· timestamp
· scalar-unit.size
· scalar-unit.time
· scalar-unit.frequency
· scalar-unit.bitrate
Collection Types: (section 4.4.3)
· list
· map
Notes that were originally in the metadata section:
Important notes:
YAML map keys can be any value, not just strings. TOSCA metadata grammar allows that full YAML expressiveness and does not add additional restrictions beyond requiring correct YAM syntax.
YAML does not specify the bit width of integers and floats but suggests that 32 bits should be acceptable.
Users should be careful about the difference between parsing floats and integers. If they explicitly want a float, they should add ".0".
Users should be careful with version strings being parsed as floats. E.g., "3.2" is a float but "3.2.1" is a string,
The TOSCA primitive types have been specified to allow for the broadest possible support for implementations.
Guiding principles:
1. Because TOSCA files are written in YAML they must support all the literal primitives in YAML. However, it is important to also allow for consistency of representation of external data, e.g. service template inputs and outputs, property and attribute values stored in a database, etc.
2. Adherence to 64-bit precision to ensure portability of numeric data.
3. TOSCA parsers shall not automatically convert between primitive types. Thus, care should be taken to use the correct YAML notation for that type. Details will be provided below.
An array of Unicode runes. (For storing an arbitrary array of bytes see the “bytes” type, below.)
Because we adhere to 64-bit precision, the minimum length of strings is 0 and the maximum length of strings is 4,294,967,295.
TOSCA does not specify a character encoding. For example, a string could be encoded as UTF-8 or UTF-16. The exact encoding used depends on the implementation.
Be aware that YAML parsers will attempt to parse unquoted character sequences as other types (booleans, integers, floats, etc.) before falling back to the !!string type. For example, the unquoted sequence “0.1” would be interpreted as a YAML !!float. Likewise, the unquoted sequence “nan” would become the !!float value of not-a-number. However, in TOSCA a string value must be specified in YAML as a !!string.
A TOSCA parser shall not attempt to convert other primitive types to strings if a string type is required. This requirement is necessary for ensuring portability, because there is no single, standard representation for the other types, e.g. scientific notations for decimals, the words “true” vs. “True” for booleans, etc. In YAML users should thus add quotation marks around literal strings that YAML would otherwise interpret as other types.
This following example would be invalid if there were no quotation marks around “0.1”:
node_types: Node: properties: name: type: string
service_template: node_templates: node: type: Node properties: name: "0.1" |
1. There are various ways to specify literal !!string data in YAML for handling indentation, newlines, as well as convenient support for line folding for multiline strings. All may be used in TOSCA. A TOSCA parser shall not modify the YAML string in any way, e.g. no trimming of whitespace or newlines. [YAML 1.2 chapter 6]
2. The TOSCA functions “concat”, “join”, “token”, “length”, “min_length”, “max_length”, and “pattern” are all Unicode-aware. Specifically, the length of a string is a count of its runes, not the length of the byte array, which may differ according to the encoding. [See XXX]
3. The TOSCA functions that check for equality, “equal” and “valid_values”, should work regardless of the Unicode encoding. For example, comparing two strings that are “!”, one of which is in UTF-8 and is encoded as “0x21”, the other which is in UTF-16 and is encoded as “0x0021”, would result in equality. For simplicity, implementations may standardize on a single encoding, e.g., UTF-8, and convert all other encodings to it. [See XXX]
4. Relatedly, although in YAML 1.2 a !!string is already defined as a Unicode sequence [YAML 1.2 section 10.1.1.3], this sequence can be variously encoded according to the character set and encoding of the YAML stream [YAML 1.2 chapter 5]. The consequence is that a TOSCA string specified in literal YAML may inherit the encoding of the YAML document. Again, implementations may prefer to convert all strings to a single encoding.
5. TOSCA strings cannot be the null value but can be empty strings (a string with length zero). [See “nil”, below]
6. YAML is a streaming format, but TOSCA strings are explicitly not streams and thus do have a size limit. Thus, TOSCA implementations should check against the size limit.
[Tal’s comment: for functions we should specify their exact behavior for various primitive types. Some won’t work on all types, e.g. “length” should not work on integers.]
A 64-bit signed integer.
For simplicity, TOSCA does not have integers of other bit widths, nor does it have an unsigned integer type. However, it is possible to enforce most of these variations using data type validation clauses [see XXX].
For example, this would be a custom data type for unsigned 16-bit integers:
data_types: UInt16: derived_from: integer validation: { $in_range: [ $value, [ 0, 0xFFFF ] ] } |
YAML allows for the standard decimal notation as well as hexadecimal and octal notations [YAML 1.2 example 2.19]. In the above example we indeed used the hexadecimal notation.
7. The JSON schema for YAML 1.2 [YAML 1.2 chapter 10.2] allows for compatibility with JSON, such that YAML would be a superset of JSON. However, note that the JSON format does not distinguish between integers and floats, and thus many JSON implementations use floats instead of integers.
8. TOSCA does not specify the endianness of integers and indeed makes no requirements for data representation.
A 64-bit (double-precision) floating-point number [IEEE 754], including the standard values for negative infinity, positive infinity, and not-a-number.
Be aware that YAML parsers will parse numbers with a decimal point as !!float even if they could be represented as !!int, and likewise numbers without a decimal point would always be parsed as !!int.
A TOSCA parser shall not attempt to convert a YAML !!int to a float. This requirement is necessary for avoiding rounding errors and ensuring portability. Users should thus add a “.0” suffix to literal integers that must be floats. Note that this even includes zero, i.e. users must specify “0” for a zero integer and “0.0” for a zero float.
This following example would be invalid if there were no “.0” suffix added to “10”:
node_types: Node: properties: velocity: type: float
service_template: node_templates: node: type: Node properties: velocity: 10.0 |
1. In addition to decimal, YAML also allows for specifying floats using scientific notation as well as special unquoted words for negative infinity, positive infinity, and not-a-number [YAML 1.2 example 2.20].
2. TOSCA does not specify how to convert to other precisions nor to other formats, e.g. Bfloat16 and TensorFloat-32.
3. TOSCA does not specify the endianness of floats and indeed makes no requirements for data representation.
A single bit.
Note that in YAML literal booleans can be only either the unquoted all-lowercase words “true” or “false”.
A TOSCA parser shall not attempt to convert these values, nor variations such as “yes” or “True”, as quoted strings to booleans, nor shall it attempt to convert integer values (such as 1 and 0) to booleans. This requirement is necessary for ensuring portability as well as clarity.
An array of arbitrary bytes. Because we adhere to 64-bit precision, the minimum length of bytes is 0 and the maximum length of bytes is 4,294,967,295.
To specify literal bytes in YAML you must use a Base64-encoded !!string [RFC 2045 section 6.8]. There exist many free tools to help you convert arbitrary data to Base64.
Example:
node_types: Node: properties: preamble: type: bytes
service_template: node_templates: node: type: Node properties: preamble: "\ R0lGODlhDAAMAIQAAP//9/X17unp5WZmZgAAAOfn515eXvPz7Y6OjuDg4J+fn5\ OTk6enp56enmlpaWNjY6Ojo4SEhP/++f/++f/++f/++f/++f/++f/++f/++f/+\ +f/++f/++f/++f/++f/++SH+Dk1hZGUgd2l0aCBHSU1QACwAAAAADAAMAAAFLC\ AgjoEwnuNAFOhpEMTRiggcz4BNJHrv/zCFcLiwMWYNG84BwwEeECcgggoBADs=" |
1. There is no standard way to represent literal bytes in YAML 1.2. Though some YAML implementations may support the !!binary type working draft, to ensure portability TOSCA implementations shall not accept this YAML type.
2. The TOSCA functions “length”, “min_length”, and “max_length” work differently for the bytes type vs. the string type. For the latter the length is the count of Unicode runes, not the count of bytes.
3. TOSCA bytes values cannot be the null value but can be empty arrays (a bytes value with length zero). [See “nil”, below]
The nil type always has the same singleton value. No other type can have this value.
This value is provided literally in YAML via the unquoted all-lowercase word “null”.
Example:
node_types: Node: properties: nothing: type: nil required: true
service_template: node_templates: node: type: Node properties: nothing: null |
Note that a nil-typed value is distinct from an unassigned value. For consistency TOSCA requires you to assign nil values even though their value is obvious. Thus, the above example would be invalid if we did not specify the null value for the property at the node template.
Following is a valid example of not assigning a value:
node_types: Node: properties: nothing: type: nil required: false
service_template: node_templates: node: type: Node |
A TOSCA version string.
TOSCA supports the concept of “reuse” of type definitions, as well as template definitions which could be versioned and change over time. It is important to provide a reliable, normative means to represent a version string which enables the comparison and management of types and templates over time.
TOSCA version strings have the following grammar:
<major_version>.<minor_version>[.<fix_version>[.<qualifier>[-<build_version] ] ] |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· major_version: is a mandatory integer value greater than or equal to 0 (zero)
· minor_version: is a mandatory integer value greater than or equal to 0 (zero).
· fix_version: is an optional integer value greater than or equal to 0 (zero).
· qualifier: is an optional string that indicates a named, pre-release version of the associated code that has been derived from the version of the code identified by the combination major_version, minor_version and fix_version numbers.
· build_version: is an optional integer value greater than or equal to 0 (zero) that can be used to further qualify different build versions of the code that has the same qualifer_string.
· When specifying a version string that contains just a major and a minor version number, the version string must be enclosed in quotes to prevent the YAML parser from treating the version as a floating point value.
· When comparing TOSCA versions, all component versions (i.e., major, minor and fix) are compared in sequence from left to right.
· TOSCA versions that include the optional qualifier are considered older than those without a qualifier.
· TOSCA versions with the same major, minor, and fix versions and have the same qualifier string, but with different build versions can be compared based upon the build version.
· Qualifier strings are considered domain-specific. Therefore, this specification makes no recommendation on how to compare TOSCA versions with the same major, minor and fix versions, but with different qualifiers strings and simply considers them different branches derived from the same code.
Examples of valid TOSCA version strings:
# basic version strings ‘6.1’ 2.0.1
# version string with optional qualifier 3.1.0.beta
# version string with optional qualifier and build version 1.0.0.alpha-10 |
· [Maven-Version] The TOSCA version type is compatible with the Apache Maven versioning policy.
· A version value of zero (i.e., ‘0.0’, or ‘0.0.0’) SHALL indicate there no version provided.
· A version value of zero used with any qualifiers SHALL NOT be valid.
The range type can be used to define numeric ranges with a lower and upper boundary. For example, this allows for specifying a range of ports to be opened in a firewall.
TOSCA range values have the following grammar:
[<lower_bound>, <upper_bound>] |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· lower_bound: is a mandatory integer value that denotes the lower boundary of the range.
· upper_bound: is a mandatory integer value that denotes the upper boundary of the range. This value MUST be greater than or equal to lower_bound.
The following Keywords may be used in the TOSCA range type:
Keyword |
Applicable Types |
Description |
UNBOUNDED |
scalar |
Used to represent an unbounded upper bounds (positive) value in a set for a scalar type. |
Example of a node template property with a range value:
# numeric range between 1 and 100 a_range_property: [ 1, 100 ]
# a property that has allows any number 0 or greater num_connections: [ 0, UNBOUNDED ] |
A local instant in time containing two elements: the local notation plus the time zone offset.
TOSCA timestamps are represented as strings following [RFC 3339], which in turn uses a simplified profile of [ISO 8601]. TOSCA adds an exception to RFC 3339: though RFC 3339 supports timestamps with unknown local offsets, represented as the "-0" timezone, TOSCA does not support this feature and will treat the unknown time zone as UTC. There are two reasons for this exception: the first is that many systems do not support this distinction and TOSCA aims for interoperability, and the second is that timestamps with unknown time zones cannot be converted to UTC, making it impossible to apply comparison functions. If this feature is required, it can be supported via a custom data type (see XXX).
· It is strongly recommended that all literal YAML timestamps be enclosed in quotation marks to ensure that they are parsed as strings. Otherwise, some YAML parsers might interpret them as the YAML !!timestamp type, which is rejected by TOSCA (see below).
· The TOSCA functions "equal", "greater_than", "greater_or_equal", "less_than", and "less_or_equal" all use the universal instant, i.e. as the local instant is converted to UTC by applying the timezone offset.
· Some YAML implementations may support the !!timestamp type working draft, but to ensure portability TOSCA implementations shall not accept this YAML type. Also note that the YAML !!timestamp supports a relaxed notation with whitespace, which does not conform to RFC 3339.
· RFC 3339 is based on the Gregorian calendar, including leap years and leap seconds, and is thus explicitly culturally biased. It cannot be used for non-Gregorian locales. Other calendar representations can be supported via custom data types (see XXX).
· Time zone information is expressed and stored numerically as an offset from UTC, thus daylight savings and other local changes are not included.
· TOSCA does not specify a canonical representation for timestamps. The only requirement is that representations adhere to RFC 3339.
The scalar-unit type can be used to define scalar values along with a unit from the list of recognized units provided below.
TOSCA scalar-unit typed values have the following grammar:
<scalar> <unit> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· scalar: is a mandatory scalar value.
· unit: is a mandatory unit value. The unit value MUST be type-compatible with the scalar.
· Whitespace: any number of spaces (including zero or none) SHALL be allowed between the scalar value and the unit value.
· It SHALL be considered an error if either the scalar or unit portion is missing on a property or attribute declaration derived from any scalar-unit type.
· When performing validation clause evaluation on values of the scalar-unit type, both the scalar value portion and unit value portion SHALL be compared together (i.e., both are treated as a single value). For example, if we have a property called storage_size (which is of type scalar-unit) a valid range constraint would appear as follows:
– storage_size: in_range [ 4 GB, 20 GB ]
where storage_size’s range will be evaluated using both the numeric and unit values (combined together), in this case ‘4 GB’ and ’20 GB’.
The scalar-unit type grammar is abstract and has four recognized concrete types in TOSCA:
· scalar-unit.size – used to define properties that have scalar values measured in size units.
· scalar-unit.time – used to define properties that have scalar values measured in size units.
· scalar-unit.frequency – used to define properties that have scalar values measured in units per second.
· scalar-unit.bitrate – used to define properties that have scalar values measured in bits or bytes per second
These types and their allowed unit values are defined below.
Unit |
Usage |
Description |
B |
size |
byte |
kB |
size |
kilobyte (1000 bytes) |
KiB |
size |
kibibytes (1024 bytes) |
MB |
size |
megabyte (1000000 bytes) |
MiB |
size |
mebibyte (1048576 bytes) |
GB |
size |
gigabyte (1000000000 bytes) |
GiB |
size |
gibibytes (1073741824 bytes) |
TB |
size |
terabyte (1000000000000 bytes) |
TiB |
size |
tebibyte (1099511627776 bytes) |
# Storage size in Gigabytes properties: storage_size: 10 GB |
· The unit values recognized by TOSCA for size-type units are based upon a subset of those defined by GNU at http://www.gnu.org/software/parted/manual/html_node/unit.html, which is a non-normative reference to this specification.
· TOSCA treats these unit values as case-insensitive (e.g., a value of ‘kB’, ‘KB’ or ‘kb’ is equivalent), but it is considered best practice to use the case of these units as prescribed by GNU.
· Some cloud providers may not support byte-level granularity for storage size allocations. In those cases, these values could be treated as desired sizes and actual allocations will be based upon individual provider capabilities.
Unit |
Usage |
Description |
d |
time |
days |
h |
time |
hours |
m |
time |
minutes |
s |
time |
seconds |
ms |
time |
milliseconds |
us |
time |
microseconds |
ns |
time |
nanoseconds |
# Response time in milliseconds properties: respone_time: 10 ms |
· The unit values recognized by TOSCA for time-type units are based upon a subset of those defined by International System of Units whose recognized abbreviations are defined within the following reference:
– http://www.ewh.ieee.org/soc/ias/pub-dept/abbreviation.pdf
– This document is a non-normative reference to this specification and intended for publications or grammars enabled for Latin characters which are not accessible in typical programming languages
Unit |
Usage |
Description |
Hz |
frequency |
Hertz, or Hz. equals one cycle per second. |
kHz |
frequency |
Kilohertz, or kHz, equals to 1,000 Hertz |
MHz |
frequency |
Megahertz, or MHz, equals to 1,000,000 Hertz or 1,000 kHz |
GHz |
frequency |
Gigahertz, or GHz, equals to 1,000,000,000 Hertz, or 1,000,000 kHz, or 1,000 MHz. |
# Processor raw clock rate properties: clock_rate: 2.4 GHz |
· The value for Hertz (Hz) is the International Standard Unit (ISU) as described by the Bureau International des Poids et Mesures (BIPM) in the “SI Brochure: The International System of Units (SI) [8th edition, 2006; updated in 2014]”, http://www.bipm.org/en/publications/si-brochure/
Unit |
Usage |
Description |
bps |
bitrate |
bit per second |
Kbps |
bitrate |
kilobit (1000 bits) per second |
Kibps |
bitrate |
kibibits (1024 bits) per second |
Mbps |
bitrate |
megabit (1000000 bits) per second |
Mibps |
bitrate |
mebibit (1048576 bits) per second |
Gbps |
bitrate |
gigabit (1000000000 bits) per second |
Gibps |
bitrate |
gibibits (1073741824 bits) per second |
Tbps |
bitrate |
terabit (1000000000000 bits) per second |
Tibps |
bitrate |
tebibits (1099511627776 bits) per second |
# Somewhere in a node template definition requirements: - link: node_filter: capabilities: - myLinkable properties: bitrate: - greater_or_equal: 10 Kbps # 10 * 1000 bits per second at least |
The list type allows for specifying multiple values for a a parameter of property. For example, if an application allows for being configured to listen on multiple ports, a list of ports could be configured using the list data type.
Note that entries in a list must be of the same type. The type (for simple entries) or schema (for complex entries) is defined by the mandatory entry_schema attribute of the respective property definition, attribute definitions, or input or output parameter definitions. Schema definitions can be arbitrarily complex (they may themselves define a list).
TOSCA lists are essentially normal YAML lists with the following grammars:
[ <list_entry_1>, <list_entry_2>, ... ] |
- <list_entry_1> - ... - <list_entry_n> |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· <list_entry_*>: represents one entry of the list.
The following example shows a list declaration with an entry schema based upon a simple integer type (which has an additional validation clause):
<some_entity>: ... properties: listen_ports: type: list entry_schema: description: listen port entry (simple integer type) type: integer validation: { $max_length: [ $value, 128 ] } |
The following example shows a list declaration with an entry schema based upon a complex type:
<some_entity>: ... properties: products: type: list entry_schema: description: Product information entry (complex type) defined elsewhere type: ProductInfo |
These examples show two notation options for defining lists:
· A single-line option which is useful for only short lists with simple entries.
· A multi-line option where each list entry is on a separate line; this option is typically useful or more readable if there is a large number of entries, or if the entries are complex.
listen_ports: [ 80, 8080 ] |
listen_ports: - 80 - 8080 |
The map type allows for specifying multiple values for a parameter of property as a map. In contrast to the list type, where each entry can only be addressed by its index in the list, entries in a map are named elements that can be addressed by their keys.
Note that entries in a map for one property or parameter must be of the same type. The type (for simple entries) or schema (for complex entries) is defined by the entry_schema attribute of the respective property definition, attribute definition, or input or output parameter definition. In addition, the keys that identify entries in a map must be of the same type as well. The type of these keys is defined by the key_schema attribute of the respective property_definition, attribute_definition, or input or output parameter_definition. If the key_schema is not specified, keys are assumed to be of type string.
TOSCA maps are normal YAML dictionaries with following grammar:
{ <entry_key_1>: <entry_value_1>, ..., <entry_key_n>: <entry_value_n> } |
<entry_key_1>: <entry_value_1> ... <entry_key_n>: <entry_value_n> |
In the above grammars, the pseudo values that appear in angle brackets have the following meaning:
· entry_key_*: is the mandatory key for an entry in the map
· entry_value_*: is the value of the respective entry in the map
The following example shows a map with an entry schema definition based upon an existing string type (which has an additional validation clause):
<some_entity>: ... properties: emails: type: map entry_schema: description: basic email address type: string validation: { $max_length: [ $value, 128 ] } |
The following example shows a map with an entry schema definition for contact information:
<some_entity>: ... properties: contacts: type: map entry_schema: description: simple contact information type: ContactInfo |
These examples show two notation options for defining maps:
· A single-line option which is useful for only short maps with simple entries.
· A multi-line option where each map entry is on a separate line; this option is typically useful or more readable if there is a large number of entries, or if the entries are complex.
# notation option for shorter maps user_name_to_id_map: { user1: 1001, user2: 1002 } |
# notation for longer maps user_name_to_id_map: user1: 1001 user2: 1002 |
A Data Type definition defines the schema for new datatypes in TOSCA.
The Data Type is a TOSCA type entity and has the common keynames listed in Section 4.2.5.2 Common keynames in type definitions. In addition, the Data Type has the following recognized keynames:
Keyname |
Mandatory |
Type |
Description |
validation |
no |
The optional validation clause that must evaluate to True for values of this Data Type to be valid. |
|
properties |
no |
map of property definitions |
The optional map property definitions that comprise the schema for a complex Data Type in TOSCA. |
key_schema |
conditional (default: string) |
For data types that derive from the TOSCA map data type, the optional schema definition for the keys used to identify entries in properties of this data type. If not specified, the key_schema defaults to string. For data types that do not derive from the TOSCA map data type, the key_schema is not allowed. |
|
entry_schema |
conditional |
For data types that derive from the TOSCA map or list data types, the mandatory schema definition for the entries in properties of this data type. For data types that do not derive from the TOSCA list or map data type, the entry_schema is not allowed. |
Data Types have the following grammar:
derived_from: <existing_type_name> version: <version_number> metadata: description: <datatype_description> validation: <validation_clause> properties: key_schema: <key_schema_definition> entry_schema: <entry_schema_definition> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· data_type_name: represents the mandatory symbolic name of the data type as a string.
· version_number: represents the optional TOSCA version number for the data type.
· datatype_description: represents the optional description for the data type.
· existing_type_name: represents the optional name of a valid TOSCA primitive type or data type this new data type derives from.
· validation_clause: represents the optional validation clause that must evaluate to True for values of this data type to be valid.
· property_definitions: represents the optional map of one or more property definitions that provide the schema for the data type
– property_definitions may not be added to data types derived_from TOSCA primitive types.
· key_schema_definition: if the data type derives from the TOSCA map type (i.e existing_type_name is a map or derives from a map), it represents the optional schema definition for the keys used to identify entry properties of this type.
· entry_schema_definition: if the data type derives from the TOSCA map or list types (i.e. existing_type name is a map or list or derives from a map or list), it represents the mandatory schema definition for the entries in properties of this type.
During Data Type derivation the keyname definitions follow these rules:
· validation: a new validation clause may be defined; this validation clause does not replace the validation clause defined in the parent type but is considered in addition to it.
· properties: existing property definitions may be refined; new property definitions may be added.
· key_schema: the key_schema definition may be refined according to schema refinement rules.
· entry_schema: the entry_schema definition may be refined according to schema refinement rules.
· A valid datatype definition MUST have either a valid derived_from declaration or at least one valid property definition.
· Any validation clauses SHALL be type-compatible with the type declared by the derived_from keyname.
· If a properties keyname is provided, it SHALL contain one or more valid property definitions.
· Property definitions may not be added to data types derived from TOSCA primitive types.
The following example represents a Data Type definition based upon an existing string type:
# define a new complex datatype mytypes.phonenumber: description: my phone number datatype properties: countrycode: type: integer areacode: type: integer number: type: integer |
# define a new datatype that derives from existing type and extends it mytypes.phonenumber.extended: derived_from: mytypes.phonenumber description: custom phone number type that extends the basic phonenumber type properties: phone_description: type: string validation: { $max_length: [ $value, 128 ] } |
All entries in a map or list for one property or parameter must be of the same type. Similarly, all keys for map entries for one property or parameter must be of the same type as well. A TOSCA schema definition specifies the type (for simple entries) or schema (for complex entries) for keys and entries in TOSCA set types such as the TOSCA list or map.
If the schema definition specifies a map key, the type of the key schema must be derived originally from the string type (which basically ensures that the schema type is a string with additional validation clauses). As there is little need for complex keys this caters to more straight-forward and clear specifications. If the key schema is not defined it is assumed to be string by default.
Schema definitions appear in data type definitions when derived_from a map or list type or in parameter, property, or attribute definitions of a map or list type.
The following is the list of recognized keynames for a TOSCA schema definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory data type for the key or entry. If this schema definition is for a map key, then the referred type must be derived originally from string. |
|
description |
no |
The optional description for the schema. |
|
validation |
no |
The optional validation clause that must evaluate to True for the property. |
|
key_schema |
no (default: string) |
When the schema itself is of type map, the optional schema definition that is used to specify the type of the keys of that map’s entries (if key_schema is not defined it is assumed to be “string” by default). For other schema types, the key_schema must not be defined. |
|
entry_schema |
conditional |
When the schema itself is of type map or list, the schema definition is mandatory and is used to specify the type of the entries in that map or list. For other schema types, the entry_schema must not be defined. |
The following single-line grammar may be used when only the schema type needs to be declared:
<schema_definition>: <schema_type> |
The following multi-line grammar may be used when additional information on the schema definition is needed:
type: <schema_type> description: <schema_description> validation: <schema_validation_clause> key_schema: <key_schema_definition> entry_schema: <entry_schema_definition> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· schema_type: represents the mandatory type name for entries of the specified schema
– if this schema definition is for a map key, then the schema_type must be derived originally from string.
· schema_description: represents the optional description of the schema definition
· schema_validation_clause: represents the optional validation clause for entries of the specified schema.
· key_schema_definition: if the schema_type is map, it represents the optional schema definition for the keys of that map’s entries.
· entry_schema_definition: if the schema_type is map or list, it represents the mandatory schema definition for the entries in that map or list.
A schema definition uses the following definition refinement rules when the containing entity type is derived:
· type: must be derived from (or the same as) the type in the schema definition in the parent entity type definition.
· description: a new definition is unrestricted and will overwrite the one inherited from the schema definition in the parent entity type definition.
· validation: a new definition is unrestricted; this validation clause does not replace the validation clause defined in the schema definition in the parent entity type but is considered in addition to it.
· key_schema: may be refined (recursively) according to schema refinement rules.
· entry_schema: may be refined (recursively) according to schema refinement rules.
A validation clause that must evaluate to True if the value for the entity it references is considered valid.
Validation clauses have the following grammar:
validation: < validation_clause> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· validation_clause: represents a Boolean expression that must evaluate to True in order for values to be valid. Any Boolean expression can be used with any function with any degree of nesting.
The Boolean expression used as a validation clause must have a mechanism for referencing the value to which the expression applies. A special-purpose function is introduced for this purpose. This function is named $value and refers to the value used for the data type or the parameter definition that contains the validation clause.
The following shows an example of validation clauses used in data type definitions:
data_types:
# Full function syntax for the $value function Count1: derived_from: integer validation: { $greater_or_equal: [ { $value: [] }, 0 ] }
# Simple function syntax for the $value function Count2: derived_from: integer validation: { $greater_or_equal: [ $value, 0 ] }
# Full function syntax with arguments FrequencyRange: properties: low: type: scalar-unit.frequency high: type: scalar-unit.frequency validation: $greater_or_equal: [ { $value: [ high ] }, { $value: [ low ] } ]
|
The following shows an example of validation clauses used in property definitions:
node_types:
Scalable: properties: minimum_instances: type: integer validation: { $greater_or_equal: [ $value, 0 ] } # positive integer maximum_instances: type: integer validation: $greater_or_equal: - $value - $get_property: [ SELF, minimum_instances ] default_instances: type: integer validation: $and: - $greater_or_equal: - $value - $get_property: [ SELF, minimum_instances ] - $less_or_equal: - $value - $get_property: [ SELF, maximum_instances ] required: false |
A property definition defines a named, typed value and related data that can be associated with an entity defined in this specification (e.g., Node Types, Relationship Types, Capability Types, etc.). Properties are used by template authors to provide input values to TOSCA entities which indicate their “desired state” when they are instantiated. The value of a property can be retrieved using the get_property function within TOSCA Service Templates.
The actual state of the entity, at any point in its lifecycle once instantiated, is reflected by an attribute. TOSCA orchestrators automatically create an attribute for every declared property (with the same symbolic name) to allow introspection of both the desired state (property) and actual state (attribute). If an attribute is reflected from a property, its initial value is the value of the reflected property.
The following is the list of recognized keynames for a TOSCA property definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory data type for the property. |
|
description |
no |
The optional description for the property. |
|
required |
No (default: true)
|
An optional key that declares a property as required (true) or not (false). Defaults to true. |
|
default |
no |
<must match property type> |
An optional key that may provide a value to be used as a default if not provided by another means. The default keyname SHALL NOT be defined when property is not required (i.e. the value of the required keyname is false). |
value |
no |
<see below> |
An optional key that may provide a fixed value to be used. A property that has a fixed value provided (as part of a definition or refinement) cannot be subject to a further refinement or assignment. That is, a fixed value cannot be changed. |
status |
No (default: supported)
|
The optional status of the property relative to the specification or implementation. See table below for valid values. Defaults to supported. |
|
validation |
no |
The optional validation clause for the property. |
|
key_schema |
conditional (default: string) |
The schema definition for the keys used to identify entries in properties of type TOSCA map (or types that derive from map). If not specified, the key_schema defaults to string. For properties of type other than map, the key_schema is not allowed. |
|
entry_schema |
conditional |
The schema definition for the entries in properties of TOSCA collection types such as list, map, or types that derive from list or map) If the property type is a collection type, the entry schema is mandatory. For other types, the entry_schema is not allowed. |
|
external-schema |
no |
string |
The optional key that contains a schema definition that TOSCA Orchestrators MAY use for validation when the “type” key’s value indicates an External schema (e.g., “json”). See section “External schema” below for further explanation and usage. |
metadata |
no |
Defines a section used to declare additional metadata information. |
The following property status values are supported:
Value |
Description |
supported |
Indicates the property is supported. This is the default value for all property definitions. |
unsupported |
Indicates the property is not supported. |
experimental |
Indicates the property is experimental and has no official standing. |
deprecated |
Indicates the property has been deprecated by a new specification version. |
Property definitions have the following grammar:
type: <property_type> description: <property_description> required: <property_required> default: <default_value> value: <property_value> | { <property_value_expression> } status: <status_value> validation: <validation_clause> key_schema: <key_schema_definition> entry_schema: <entry_schema_definition> metadata: |
The following single-line grammar is supported when only a fixed value or fixed value expression needs to be provided to a property:
<property_name>: <property_value> | { <property_value_expression> } |
This single-line grammar is equivalent to the following:
value: <property_value> | { <property_value_expression> } |
Note that the short form can be used only during a refinement (i.e. the property has been previously defined).
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· property_name: represents the mandatory symbolic name of the property as a string.
· property_description: represents the optional description of the property.
· property_type: represents the mandatory data type of the property.
· property_required: represents an optional boolean value (true or false) indicating whether or not the property is required. If this keyname is not present on a property definition, then the property SHALL be considered required (i.e., true) by default.
· default_value: contains a type-compatible value that is used as a default value if a value is not provided by another means (via the fixed_value definition or via property assignment);
– the default_value shall not be defined for properties that are not required (i.e. property_required is “false”) as they will stay undefined.
· <property_value> | { <property_value_expression> }: contains a type-compatible value or value expression that may be defined during property definition or refinement to set and fix the value definition of the property
– note that a value definition cannot be changed; once defined, the property cannot be further refined or assigned. Thus, value definitions should be avoided in data_type definitions.
· status_value: a string that contains a keyword that indicates the status of the property relative to the specification or implementation.
· validation_clause: represents the optional Boolean expression that must evaluate to true for a value of this property to be valid.
· entry_schema_definition: if the property_type is map or list, represents the mandatory schema definition for the entries in that map or list.
· metadata_map: represents the optional map of string.
A property definition within data, capability, node, relationship, group, policy, and artifact types (including capability definitions in node types) matching the name of a property in the derived entity type uses the following refinement rules to combine the two property definitions together:
· type: must be derived from (or the same as) the type in the property definition in the parent entity type definition.
· description: a new definition is unrestricted and will overwrite the one inherited from the property definition in the parent entity type definition.
· required: if defined to “false” in the property definition parent entity type it may be redefined to “true”; note that if undefined it is automatically considered as being defined to “true”.
· default: a new definition is unrestricted and will overwrite the one inherited from the property definition in the parent entity type definition (note that the definition of a default value is only allowed if the required keyname is (re)defined as “true”).
· value: if undefined in the property definition in the parent entity type, it may be defined to any type-compatible value; once defined, the property cannot be further refined or assigned.
· status: a new definition is unrestricted and will overwrite the one inherited from the property definition in the parent entity type definition.
· validation: a new definition is unrestricted; this validation clause does not replace the validation clause defined in the property definition in the parent entity type but is considered in addition to it.
· key_schema: if defined in the property definition in the parent entity type it may be refined according to schema refinement rules.
· entry_schema: if defined in the property definition in the parent entity type it may be refined according to schema refinement rules.
· metadata: a new definition is unrestricted and will overwrite the one inherited from the property definition in the parent entity type definition.
· Implementations of TOSCA SHALL automatically reflect (i.e., make available) any property defined on an entity as an attribute of the entity with the same name as the property.
· A property SHALL be considered required by default (i.e., as if the required keyname on the definition is set to true) unless the definition’s required keyname is explicitly set to false.
· The value provided on a property definition’s default keyname SHALL be type compatible with the type declared on the definition’s type keyname.
· If a key_schema or entry_schema keyname is provided, its value (string) MUST represent a valid schema definition that matches the property type (i.e. the property type as defined by the type keyword must be the same as or derived originally from map (for key_schema) or map or list (for entry_schema).
· TOSCA Orchestrators MAY choose to validate the value of the ‘schema’ keyname in accordance with the corresponding schema specification for any recognized external types.
The following represents an example of a property definition with a validation clause:
properties: num_cpus: type: integer description: Number of CPUs requested for a software node instance. default: 1 required: true validation; { $valid_values: [ $value, [ 1, 2, 4, 8 ] ] } |
The following shows an example of a property refinement. Consider the definition of an Endpoint capability type:
derived_from: tosca.capabilities.Root properties: protocol: type: string required: true default: tcp port: type: PortDef required: false secure: type: boolean required: false default: false # Other property definitions omitted for brevity |
The Endpoint.Admin capability type refines the secure property of the Endpoint capability type from which it derives by forcing its value to always be true:
tosca.capabilities.Endpoint.Admin: derived_from: tosca.capabilities.Endpoint # Change Endpoint secure indicator to true from its default of false properties: secure: true |
This section defines the grammar for assigning values to properties within TOSCA templates.
The TOSCA property assignment has no keynames.
Property assignments have the following grammar:
The following single-line grammar may be used when a simple value assignment is needed:
<property_name>: <property_value> | { <property_value_expression> } |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· property_name: represents the name of a property that will be used to select a property definition with the same name within on a TOSCA entity (e.g., Node Template, Relationship Template, etc.) which is declared in its declared type (e.g., a Node Type, Node Template, Capability Type, etc.).
· property_value, property_value_expression: represent the type-compatible value to assign to the property. Property values may be provided as the result of the evaluation of an expression or a function.
· Properties that have a (fixed) value defined during their definition or during a subsequent refinement may not be assigned (as their value is already set).
· If a required property has no value defined or assigned, its default value is assigned
· A non-required property that is not assigned it stays undefined, thus the default keyname is irrelevant for a non-required property.
An attribute definition defines a named, typed value that can be associated with an entity defined in this specification (e.g., a Node, Relationship or Capability Type). Specifically, it is used to expose the “actual state” of some property of a TOSCA entity after it has been deployed and instantiated (as set by the TOSCA orchestrator). Attribute values can be retrieved via the get_attribute function from the instance model and used as values to other entities within TOSCA Service Templates.
The actual state of the entity, at any point in its lifecycle once instantiated, is reflected by an attribute. TOSCA orchestrators automatically create an attribute for every declared property (with the same symbolic name) to allow introspection of both the desired state (property) and actual state (attribute). If an attribute is reflected from a property, its initial value is the value of the reflected property.
The following is the list of recognized keynames for a TOSCA attribute definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory data type for the attribute. |
|
description |
no |
The optional description for the attribute. |
|
default |
no |
<any> |
An optional key that may provide a value to be used as a default if not provided by another means.
This value SHALL be type compatible with the type declared by the attribute definition’s type keyname. |
status |
no |
The optional status of the attribute relative to the specification or implementation. See supported status values . Defaults to supported. |
|
validation |
no |
The optional validation clause for the attribute. |
|
key_schema |
conditional (default: string) |
The schema definition for the keys used to identify entries in attributes of type TOSCA map (or types that derive from map). If not specified, the key_schema defaults to string. For attributes of type other than map, the key_schema is not allowed. |
|
entry_schema |
conditional |
The schema definition for the entries in attributes of TOSCA collection types such as list, map, or types that derive from list or map) If the attribute type is a collection type, the entry schema is mandatory. For other types, the entry_schema is not allowed. |
|
metadata |
no |
Defines a section used to declare additional metadata information. |
Attribute definitions have the following grammar:
attributes: type: <attribute_type> description: <attribute_description> default: <default_value> status: <status_value> validation: <attribute_validation_clause> key_schema: <key_schema_definition> entry_schema: <entry_schema_definition> metadata: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· attribute_name: represents the mandatory symbolic name of the attribute as a string.
· attribute_type: represents the mandatory data type of the attribute.
· attribute_description: represents the optional description of the attribute.
· default_value: contains a type-compatible value that may be used as a default if not provided by another means.
· status_value: contains a value indicating the attribute’s status relative to the specification version (e.g., supported, deprecated, etc.); supported status values for this keyname are defined in the property definition section.
· attribute_validation_clause: represents the optional validation clause that must evaluate to True for values for the defined attribute to be valid.
· key_schema_definition: if the attribute_type is map, represents the optional schema definition for the keys used to identify entries in that map.
· entry_schema_definition: if the attribute_type is map or list, represents the mandatory schema definition for the entries in that map or list.
· metadata_map: represents the optional map of string.
An attribute definition within data, capability, node, relationship, and group types (including capability definitions in node types) uses the following refinement rules when the containing entity type is derived:
· type: must be derived from (or the same as) the type in the attribute definition in the parent entity type definition.
· description: a new definition is unrestricted and will overwrite the one inherited from the attribute definition in the parent entity type definition.
· default: a new definition is unrestricted and will overwrite the one inherited from the attribute definition in the parent entity type definition.
· status: a new definition is unrestricted and will overwrite the one inherited from the attribute definition in the parent entity type definition.
· validation: a new definition is unrestricted; this validation clause does not replace the validation clause defined in the attribute definition in the parent entity type but is considered in addition to it.
· key_schema: if defined in the attribute definition in the parent entity type it may be refined according to schema refinement rules.
· entry_schema: if defined in the attribute definition in the parent entity type it may be refined according to schema refinement rules.
· metadata: a new definition is unrestricted and will overwrite the one inherited from the attribute definition in the parent entity type definition
· In addition to any explicitly defined attributes on a TOSCA entity (e.g., Node Type, Relationship Type, etc.), implementations of TOSCA MUST automatically reflect (i.e., make available) any property defined on an entity as an attribute of the entity with the same name as the property.
· Values for the default keyname MUST be derived or calculated from other attribute or operation output values (that reflect the actual state of the instance of the corresponding resource) and not hard-coded or derived from a property settings or inputs (i.e., desired state).
· Attribute definitions are very similar to Property definitions; however, properties of entities reflect an input that carries the template author’s requested or desired value (i.e., desired state) which the orchestrator (attempts to) use when instantiating the entity whereas attributes reflect the actual value (i.e., actual state) that provides the actual instantiated value.
– For example, a property can be used to request the IP address of a node using a property (setting); however, the actual IP address after the node is instantiated may by different and made available by an attribute.
The following represents a mandatory attribute definition:
actual_cpus: type: integer description: Actual number of CPUs allocated to the node instance. |
This section defines the grammar for assigning values to attributes within TOSCA templates.
The TOSCA attribute assignment has no keynames.
Attribute assignments have the following grammar:
The following single-line grammar may be used when a simple value assignment is needed:
<attribute_name>: <attribute_value> | { <attribute_value_expression> } |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· attribute_name: represents the name of an attribute that will be used to select an attribute definition with the same name within on a TOSCA entity (e.g., Node Template, Relationship Template, etc.) which is declared (or reflected from a Property definition) in its declared type (e.g., a Node Type, Node Template, Capability Type, etc.).
· attribute_value, attribute_value_expresssion: represent the type-compatible value to assign to the attribute. Attribute values may be provided as the result from the evaluation of an expression or a function.
· Attributes that are the target of a parameter mapping assignment cannot also be assigned a value using an attribute assignment.
A parameter definition defines a named, typed value and related data and may be used to exchange values between the TOSCA orchestrator and the external world. Such values may be
· inputs and outputs of interface operations and notifications
· inputs and outputs of workflows
· inputs and outputs of service templates
From the perspective of the TOSCA orchestrator such parameters are either “incoming” (i.e. transferring a value from the external world to the orchestrator) or “outgoing” (transferring a value from the orchestrator to the external world). Thus:
· outgoing parameters are:
– template outputs
– internal workflow outputs
– external workflow inputs
– operation inputs
· incoming parameters are:
– template inputs
– internal workflow inputs
– external workflow outputs
– operation outputs
– notification outputs
An “outgoing” parameter definition is essentially the same as a TOSCA property definition, however it may optionally inherit the data type of the value assigned to it rather than have an explicit data type defined.
An “incoming” parameter definition may define an attribute mapping of the parameter value to an attribute of a node. Optionally, it may inherit the data type of the attribute it is mapped to, rather than have an explicit data type defined for it.
The TOSCA parameter definition has all the keynames of a TOSCA property definition with the following additional or changed keynames:
Keyname |
Mandatory |
Type |
Description |
type |
no |
The data type of the parameter.
Note: This keyname is mandatory for a TOSCA Property definition but is not mandatory for a TOSCA Parameter definition. |
|
value |
no |
<any> |
The type-compatible value to assign to the parameter. Parameter values may be provided as the result from the evaluation of an expression or a function. May only be defined for outgoing parameters. Mutually exclusive with the “mapping” keyname. |
mapping |
no |
A mapping that specifies the node or relationship attribute into which the returned output value must be stored. May only be defined for incoming parameters. Mutually exclusive with the “value” keyname. |
Parameter definitions have the following grammar:
type: <parameter_type> description: <parameter_description> value: <parameter_value> | { <parameter_value_expression> } required: <parameter_required> default: <parameter_default_value> status: <status_value> validation: <parameter_validation_clause> key_schema: <key_schema_definition> entry_schema: <entry_schema_definition> mapping: <attribute_selection_form> |
The following single-line grammar is supported when only a fixed value needs to be provided provided to an outgoing parameter:
<parameter_name>: <parameter_value> | { <parameter_value_expression> } |
This single-line grammar is equivalent to the following:
value: <parameter_value> | { <parameter_value_expression> } |
The following single-line grammar is supported when only a parameter to attribute mapping needs to be provided to an incoming parameter:
This single-line grammar is equivalent to the following:
mapping: <attribute_selection_form> |
Note that the context of the parameter definition unambiguously determines if the parameter is an incoming or an outgoing parameter.
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· parameter_name: represents the mandatory symbolic name of the parameter as a string.
· parameter_description: represents the optional description of the parameter.
· parameter_type: represents the optional data type of the parameter. Note, this keyname is mandatory for a TOSCA Property definition, but is not for a TOSCA Parameter definition.
· parameter_value, parameter_value_expresssion: represent the type-compatible value to assign to the parameter. Parameter values may be provided as the result from the evaluation of an expression or a function.
– once the value keyname is defined, the parameter cannot be further refined or assigned.
– the value keyname is relevant only for “outgoing” parameter definitions and SHOULD NOT be defined in “incoming” parameter definitions.
· parameter_required: represents an optional boolean value (true or false) indicating whether or not the parameter is required. If this keyname is not present on a parameter definition, then the parameter SHALL be considered required (i.e., true) by default.
· default_value: contains a type-compatible value that may be used as a default if not provided by other means.
– the default keyname SHALL NOT be defined for parameters that are not required (i.e. parameter_required is “false”) as they will stay undefined.
· status_value: a string that contains a keyword that indicates the status of the parameter relative to the specification or implementation.
· parameter_validation_clause: represents the optional validation clause on the parameter definition.
· key_schema_definition: if the parameter_type is map, represents the optional schema definition for the keys used to identify entries in that map. Note that if the key_schema is not defined, the key_schema defaults to string.
· entry_schema_definition: if the parameter_type is map or list, represents the mandatory schema definition for the entries in that map or list.
· attribute_selection_form: a list that corresponds to a valid attribute_selection_format; the parameter is mapped onto an attribute of the containing entity
– the mapping keyname is relevant only for “incoming” parameter definitions and SHOULD NOT be defined in “outgoing” parameter definitions.
A parameter definition within interface types, interface definitions in node and relationship types, uses the following refinement rules when the containing entity type is derived:
· type: must be derived from (or the same as) the type in the parameter definition in the parent entity type definition.
· description: a new definition is unrestricted and will overwrite the one inherited from the parameter definition in the parent entity type definition.
· required: if defined to “false” in the parameter definition parent entity type it may be redefined to “true”; note that if undefined it is automatically considered as being defined to “true”.
· default: a new definition is unrestricted and will overwrite the one inherited from the parameter definition in the parent entity type definition (note that the definition of a default value is only allowed if the required keyname is (re)defined as “true”).
· value: if undefined in the parameter definition in the parent entity type, it may be defined to any type-compatible value; once defined, the parameter cannot be further refined or assigned
– the value keyname should be defined only for “outgoing” parameters.
· mapping: if undefined in the parameter definition in the parent entity type, it may be defined to any type-compatible attribute mapping; once defined, the parameter cannot be further refined or mapped
– the mapping keyname should be defined only for “incoming” parameters.
· status: a new definition is unrestricted and will overwrite the one inherited from the parameter definition in the parent entity type definition.
· validation: a new definition is unrestricted; this validation clause does not replace the validation clause defined in the parameter definition in the parent entity type but is considered in addition to it.
· key_schema: if defined in the parameter definition in the parent entity type it may be refined according to schema refinement rules.
· entry_schema: if defined in the parameter definition in the parent entity type it may be refined according to schema refinement rules.
· metadata: a new definition is unrestricted and will overwrite the one inherited from the parameter definition in the parent entity type definition.
· A parameter SHALL be considered required by default (i.e., as if the required keyname on the definition is set to true) unless the definition’s required keyname is explicitly set to false.
· The value provided on a parameter definition’s default keyname SHALL be type compatible with the type declared on the definition’s type keyname.
The following represents an example of an input parameter definition with a validation clause:
inputs: cpus: type: integer description: Number of CPUs for the server. validation: { $valid_values: [ $value, [ 1, 2, 4, 8 ] ] } |
The following represents an example of an (untyped) output parameter definition:
outputs: server_ip: description: The private IP address of the provisioned server. value: { $get_attribute: [ my_server, private_address ] } |
This section defines the grammar for assigning values to “outgoing” parameters in TOSCA templates.
The TOSCA parameter value assignment has no keynames.
Parameter value assignments have the following grammar:
<parameter_name>: <parameter_value> | { <parameter_value_expression> } |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· parameter_name: represents the symbolic name of the parameter to assign; note that in some cases, even parameters that do not have a corresponding definition in the entity type of the entity containing them may be assigned (see e.g. inputs and outputs in interfaces).
· parameter_value, parameter_value_expression: represent the type-compatible value to assign to the parameter. Parameter values may be provided as the result from the evaluation of an expression or a function.
· Parameters that have a (fixed) value defined during their definition or during a subsequent refinement may not be assigned (as their value is already set).
· If a required parameter has no value defined or assigned, its default value is assigned.
· A non-required parameter that has no value assigned it stays undefined, thus the default keyname is irrelevant for a non-required parameter.
A parameter to attribute mapping defines an “incoming” parameter value (e.g. an output value that is expected to be returned by an operation implementation) and a mapping that specifies the node or relationship attribute into which the returned “incoming” parameter value must be stored.
The TOSCA parameter mapping assignment has no keynames.
Parameter mapping assignments have the following grammar:
<parameter_name>: <attribute_selection_format> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· parameter_name: represents the symbolic name of the parameter to assign; note that in some cases, even parameters that do not have a corresponding definition in the entity type of the entity containing them may be assigned (see e.g. inputs and outputs in interfaces).
· attribute_selection_format: represents a format that is used to select an attribute or a nested attribute on which to map the parameter value of the incoming parameter referred by parameter_name.
The attribute_selection_format is a list of the following format:
[<tosca_traversal_path>, <attribute_name>, <nested_attribute_name_or_index_1>, ..., <nested_attribute_name_or_index_n> ] |
The various entities in this grammar are defined as follows:
Parameter |
Mandatory |
Description |
<tosca_traversal_path> |
yes |
Using the <tosca_traversal_path> we can traverse the representation graph to reach the attribute we need to store the output value into. The specification of the <tosca_traversal_path> is explicated in section 6.4.2 get_property.
Note that while the <tosca_traversal_path> is very powerful, its usage should normally be restricted to reach attributes in the local node ore relationship (i.e. SELF) or in a local capability definition. |
<attribute_name> |
yes |
The name of the attribute into which the output value must be stored. |
<nested_attribute_name_or_index_or_key_*> |
no |
Some TOSCA attributes are complex (i.e., composed as nested structures). These parameters are used to dereference into the names of these nested structures when needed. Some attributes represent list or map types. In these cases, an index or key may be provided to reference a specific entry in the list or map (identified by the previous parameter). |
Note that it is possible for multiple operations to define outputs that map onto the same attribute value. For example, a create operation could include an output value that sets an attribute to an initial value, and the subsequence configure operation could then update that same attribute to a new value.
It is also possible that a node template assigns a value to an attribute that has an operation output mapped to it (including a value that is the result of calling an intrinsic function). Orchestrators could use the assigned value for the attribute as its initial value. After the operation runs that maps an output value onto that attribute, the orchestrator must then use the updated value, and the value specified in the node template will no longer be used.
· Parameters that have a mapping defined during their definition or during a subsequent refinement may not be assigned (as their mapping is already set).
TOSCA supports the use of functions for providing dynamic service data values at runtime. The syntax of
a function has two representations:
· Any function can be represented by a YAML map with a single key, where the key is a string starting with a $ (dollar sign) character and where the remainder of the string represents the function name. If present, the value in the key-value pair represents the function arguments.
· A function without arguments can alternatively be represented by a YAML string value, where the string starts with a $ (dollar sign) character and where the remainder of the string represents the function name. This representation cannot be used in map keys.
· Function names may not contain the $ character as it will conflict with the escape mechanisms described below.
Therefore, any string starting with a $ (dollar sign) character will be interpreted as a function call. To allow for strings starting with $ character to be specified, the $ character at the start of the string needs to be escaped by using $$ (two dollar signs) characters instead. For example:
· $$name will represent the literal string $name
· $$$item will represent the literal string $$item, as only the first $ character is escaped.
As we could have function calls that return values to be used as keys in a map, hypothetically it is possible that we use the same function call as a YAML key more than once. Because YAML does not allow for duplicate map keys, in such cases we must allow for key variation. This is achieved by adding suffixes after the function name starting with a second $ character. For example, the following is a valid map where the function “keygen” is called three times and the returned values are used as keys in the hint map:
hint: { $keygen: [ UUID ] }: 34 { $keygen$1: [ UUID ] }: 56 { $keygen$2: [ UUID ] }: 78 |
TOSCA functions may be used wherever a value is expected, such as:
· a value for a TOSCA keyname
· a value for a parameter or property or attribute, including a value within a complex datatype
· a value for the arguments of another function
· other places such as in validation clauses, conditions, etc.
TOSCA parsers are expected to evaluate function values at runtime based on the provided function arguments.
The following snippet shows an example of a node template that uses a function to retrieve a security context at runtime:
properties: context: { $get_security_context: { env: staging, role: admin } } |
Nested functions are supported, that is, functions can be used in the arguments of another function. The result of the internal function will be passed as an argument to the outer function:
properties: nested: {$outer_func: [{$inner_func: [iarg1, iarg2]}, oarg2]} |
To allow for strings that are not function names to start with $, the dollar sign can be escaped by using $$ (two consecutive dollar characters). The following snippet shows escaped strings in a map that do not represent function calls:
properties: prop1: $$myid1: myval1 myid2: $$myval2 $$myid3: $$myval3 |
The arguments to the functions can be arbitrary TOSCA data, although TOSCA defines a number of built-in functions that define function-specific syntax for providing arguments. In addition, service designers can optionally define custom function signatures definitions for function arguments and function return values as specified in section 1.1.1.
When parsing TOSCA files, TOSCA parsers MUST identify functions wherever values are specified using the following algorithm:
· Does the YAML string start with $?
o If yes, is the second character $?
§ If yes, discard the first $ and stop here (escape).
§ If no, is this a key in a YAML map?
· If yes, is this the only key in a YAML map?
o If yes, this is a function call.
o If no, emit a parsing syntax error ("malformed function").
· If no, this is a function call without arguments.
TOSCA includes grammar for defining function signatures and associated implementation artifacts in TOSCA profiles or in TOSCA service templates. This allows for validation of function return values and function arguments at design time, and the possibility to provide function implementation artifacts within CSARs. Note that the use of custom function definitions is entirely optional, service designers can use custom functions without defining associated function signatures and instead rely on support for those functions directly in the TOSCA orchestrator that will be used to process the TOSCA files. Of course, TOSCA processors may support custom functions that are not user-defined.
The following is the list of recognized keynames for TOSCA function definition:
Keyname |
Mandatory |
Type |
Description |
signatures |
yes |
map of signature definitions |
The map of signature definitions. |
description |
no |
The description of the function. |
|
metadata |
no |
map of metadata |
Defines additional metadata information. |
The following is the list of recognized keynames for TOSCA function signature definition:
Keyname |
Mandatory |
Type |
Description |
arguments |
no |
list of schema definitions |
All defined arguments must be used in the function invocation (and in the order defined here). If no arguments are defined, the signature either accepts no argumats or any arguments of any form (depending on if the variadic keyname is false or true). |
optional_arguments |
no |
list of schema definitions |
Optional arguments may be used in the function invocation after the regular arguments. Still the order defined here must be respected. |
variadic |
no (default: false) |
boolean |
Specifies if the last defined argument (or optional_argument if defined) may be repeated any number of times in the function invocation |
result |
no |
schema definition |
Defines the type of the function result. If no result keyname is defined, then the function may return any result |
implementation |
no
|
implementation definition |
Defines the implementation (e.g., artifact) for the function. The same definition as for operation/notification implementation is used. |
Function signatures can be defined in TOSCA profiles or TOSCA service templates using a YAML map under the functions keyname as follows. Note that this grammar allows the definition of functions that have arguments expressed within a YAML seq, however intrinsic functions may accept other argument definition syntaxes.
functions: <function_def> <function_def> ... <function_def> |
Each <function_def> defines the name of a function with an associated list of signature definitions as follows:
<function_name>: signatures: - <signature_def> - <signature_def> - <signature_def> ... - <signature_def> description: <string> metadata: <map_of_metadata> |
Only the signatures keyname is mandatory and must provide at least one signature definition. Note that the signatures are tested in the order of their definition. The first matching implementation is used.
Each <signature_def> is a map of following keywords definitions:
arguments: - <schema_def> - <schema_def> ... - <schema_def> optional_arguments: - <schema_def> - <schema_def> ... - <schema_def> variadic: <boolean> result: <schema_def> implementation: <implementation_def> |
None of the keynames in the signature definition are mandatory.
The keynames have the following meaning:
The functions section can be defined both outside and/or inside a service_template section:
properties: rnd_nr: { $namespace1:random_generator: [ seed ] } |
Function definitions inside a service_template that are having the same <function_name> are considered a refinement of the homonymous definition outside the service_template.
· description: a new definition is unrestricted and will overwrite the one inherited from the function definition outside the service_template.
· metadata: a new definition is unrestricted and will overwrite the one inherited from the function definition outside the service_template.
The following example shows the definition of a square root function:
functions: sqrt: signatures: - arguments: - type: integer validation: { $greater_or_equal: [ $value, 0 ] } result: type: float implementation: scripts/sqrt.py - arguments: - type: float validation: { $greater_or_equal: [ $value, 0.0 ] } result: type: float implementation: scripts/sqrt.py description: > This is a square root function that defines two signatures: the argument is either integer or float and the function returns the suare root as a float. |
The next sqrt is similar to above, but uses a simplified type notation (in this short form no validation clause can be expressed):
functions: sqrt: signatures: - arguments: [ integer ] result: float implementation: scripts/sqrt.py - arguments: [ float ] result: float implementation: scripts/sqrt.py description: > This is a square root function that defines two signatures: the argument is either integer or float and the function returns the suare root as a float. |
The following example shows a function that takes a list of arguments with different types:
functions: my_func_with_different_argument_types: signatures: - arguments: - type: MyType1 description: "this is the first argument ..." - type: string description: "this is the second argument ..." - type: string description: "this is the third argument ..." - type: MyType2 description: "this is the argument that can be repeated ..." variadic: true result: type: MyTypeRez implementation: scripts/my.py |
Same as the above, but in compact notation:
functions: my_func_with_different_argument_types: signatures: - arguments: [MyType1, string, string, MyType2] variadic: true result: MyTypeRez implementation: scripts/my.py |
The arguments list can be empty or completely missing. In such a case, when using the function the arguments will be an empty list:
functions: get_random_nr: signatures: - result: float implementation: scripts/myrnd.py |
Function signatures with different types within the arguments and result lists:
functions: union: signatures: - arguments: - type: list entry_schema: integer variadic: true result: type: list entry_schema: integer implementation: scripts/libpi.py - arguments: - type: list entry_schema: float variadic: true result: type: list entry_schema: float implementation: scripts/libpi.py |
The following shows the use of a argument that is a map of lists of MyType:
functions: complex_arg_function: signatures: - arguments: - type: map key_schema: string entry_schema: type: list entry_schema: MyType result: string implementation: scripts/complex.py |
The following shows more examples of function usage. Note that in the usage of the polymorphic union function, the TOSCA parser knows to identify the right signature via the types of the function arguments. Also note the usage of a user-defined function with no parameters; an empty list is used for the arguments.
properties: integer_union: {$union: [[1, 7], [3, 4, 9], [15, 16]]} float_union: {$union: [[3.5, 8.8], [1.3]]} rnd: {$get_random_nr: []} |
A substitution mapping allows a given service template to be used as an implementation of abstract node templates of a specific node type. This allows the consumption of complex systems using a simplified vision.
Keyname |
Mandatory |
Type |
Description |
node_type |
yes |
string |
The mandatory name of the Node Type the service template is providing an implementation for. |
substitution_filter |
no |
The optional filter that further constrains the abstract node templates for which this service template can provide an implementation. |
|
properties |
no |
map of property mappings |
The optional map of properties mapping allowing to map properties of the node_type to inputs of the service template. |
attributes |
no |
map of attribute mappings |
The optional map of attribute mappings allowing to map outputs from the service template to attributes of the node_type. |
capabilities |
no |
map of capability mappings |
The optional map of capabilities mapping. |
requirements |
no |
map of requirement mappings |
The optional map of requirements mapping. |
interfaces |
no |
map of interfaces mappings |
The optional map of interface mapping allows to map an interface and operations of the node type to implementations that could be either workflows or node template interfaces/operations. |
The grammar of the substitution_mapping section is as follows:
node_type: <node_type_name> substitution_filter : <node_filter> properties: <property_mappings> capabilities: <capability_mappings> requirements: <requirement_mappings> attributes: <attribute_mappings> interfaces: <interface_mappings> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· node_type_name: represents the mandatory Node Type name that the Service Template is offering an implementation for.
· node_filter: represents the optional node filter that reduces the set of abstract node templates for which this service template is an implementation by only substituting for those node templates whose properties and capabilities satisfy the condition expression specified in the node filter.
· properties: represents the <optional> map of properties mappings.
· capability_mappings: represents the <optional> map of capability mappings.
· requirement_mappings: represents the <optional> map of requirement mappings.
· attributes: represents the <optional> map of attributes mappings.
· interfaces: represents the <optional> map of interfaces mappings.
· The substitution mapping MUST provide mapping for every property, capability and requirement defined in the specified <node_type>
· The node_type specified in the substitution mapping SHOULD be abstract (does not provide implementation for normative operations).
A property mapping allows to map the property of a substituted node type to an input of the service template.
The following is the list of recognized keynames for a TOSCA property mapping:
Keyname |
Mandatory |
Type |
Description |
mapping |
no |
list of strings |
An array with 1 string element that references an input of the service. |
value |
no |
matching the type of this property |
This deprecated keyname allows to explicitly assigne a value to this property. This field is mutually exclusive with the mapping keyname. |
The single-line grammar of a property_mapping is as follows:
<property_name>: <property_value> # This use is deprecated <property_name>: [ <input_name> ] |
The multi-line grammar is as follows :
<property_name>: mapping: [ < input_name > ] <property_name>: value: <property_value> # This use is deprecated |
· Single line grammar for a property value assignment is not allowed for properties of type in order to avoid collision with the mapping single line grammar.
· The property_value mapping grammar has been deprecated. The original intent of the property-to-constant-value mapping was not to provide a mapping, but rather to present a matching mechanism to drive selection of the appropriate substituting template when more than one template was available as a substitution for the abstract node. In that case, a service template was only a valid candidate for substitution if the property value in the abstract node template matched the constant value specified in the property_value mapping for that property. With the introduction of substitution filter syntax to drive matching, there is no longer a need for the property-to-constant-value mapping functionality.
· The previous version of the specification allowed direct mappings from properties of the abstract node template to properties of node templates in the substituting service template. Support for these mappings has been deprecated since they would have resulted in unpredictable behavior, for the following reason. If the substituting template is a valid TOSCA template, then all the (required) properties of all its node templates must have valid property assignments already defined. If the substitution mappings of the substituting template include direct property-to-property mappings, the the substituting template ends up with two conflicting property assignments: one defined in the substituting template itself, and one defined by the substitution mappings. These conflicting assignments lead to unpredictable behavior.
· When Input mapping it may be referenced by multiple nodes in the topologies with resulting attributes values that may differ later on in the various nodes. In any situation, the attribute reflecting the property of the substituted type will remain a constant value set to the one of the input at deployment time.
An attribute mapping allows to map the attribute of a substituted node type an output of the service template.
The following is the list of recognized keynames for a TOSCA attribute mapping:
Keyname |
Mandatory |
Type |
Description |
mapping |
no |
list of strings |
An array with 1 string element that references an output of the service. |
The single-line grammar of an attribute_mapping is as follows:
<attribute_name>: [ <output_name> ] |
A capability mapping allows to map the capability of one of the nodes of the service template to the capability of the node type the service template offers an implementation for.
The following is the list of recognized keynames for a TOSCA capability mapping:
Keyname |
Mandatory |
Type |
Description |
mapping |
no |
list of strings (with 2 members) |
A list of strings with 2 members, the first one being the name of a node template, the second the name of a capability of the specified node template. |
properties |
no |
map of property assignments |
This field is mutually exclusive with the mapping keyname and allows to provide a capability assignment for the template and specify it’s related properties. |
attributes |
no |
map of attributes assignments |
This field is mutually exclusive with the mapping keyname and allows to provide a capability assignment for the template and specify it’s related attributes. |
The single-line grammar of a capability_mapping is as follows:
<capability_name>: [ <node_template_name>, <node_template_capability_name> ] |
The multi-line grammar is as follows :
<capability_name>: mapping: [ <node_template_name>, <node_template_capability_name> ] properties: <property_name>: <property_value> attributes: <attribute_name>: <attribute_value> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· capability_name: represents the name of the capability as it appears in the Node Type definition for the Node Type (name) that is declared as the value for on the substitution_mappings’ “node_type” key.
· node_template_name: represents a valid name of a Node Template definition (within the same service_template declaration as the substitution_mapping is declared).
· node_template_capability_name: represents a valid name of a capability definition within the <node_template_name> declared in this mapping.
· property_name: represents the name of a property of the capability.
· property_value: represents the value to assign to a property of the capability.
· attribute_name: represents the name a an attribute of the capability.
· attribute_value: represents the value to assign to an attribute of the capability.
A requirement mapping allows to map the requirement of one of the nodes of the service template to the requirement of the node type the service template offers an implementation for.
The following is the list of recognized keynames for a TOSCA requirement mapping:
Keyname |
Mandatory |
Type |
Description |
mapping |
no |
list of strings (2 members) |
A list of strings with 2 elements, the first one being the name of a node template, the second the name of a requirement of the specified node template. |
properties |
no |
List of property assignment |
This field is mutually exclusive with the mapping keyname and allow to provide a requirement for the template and specify it’s related properties. |
attributes |
no |
List of attributes assignment |
This field is mutually exclusive with the mapping keyname and allow to provide a requirement for the template and specify it’s related attributes. |
The single-line grammar of a requirement_mapping is as follows:
<requirement_name>: [ <node_template_name>, <node_template_requirement_name> ] |
The multi-line grammar is as follows :
<requirement_name>: mapping: [ <node_template_name>, <node_template_requirement_name> ] properties: <property_name>: <property_value> attributes: <attribute_name>: <attribute_value> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· requirement_name: represents the name of the requirement as it appears in the Node Type definition for the Node Type (name) that is declared as the value for on the substitution_mappings’ “node_type” key.
· node_template_name: represents a valid name of a Node Template definition (within the same service_template declaration as the substitution_mapping is declared).
· node_template_requirement_name: represents a valid name of a requirement definition within the <node_template_name> declared in this mapping.
· property_name: represents the name of a property of the requirement.
· property_value: represents the value to assign to a property of the requirement.
· attribute_name: represents the name of an attribute of the requirement.
· attribute_value: represents the value to assign to an attribute of the requirement.
An interface mapping allows to map a workflow of the service template to an operation of the node type the service template offers an implementation for.
The grammar of an interface_mapping is as follows:
<interface_name>: <operation_name>: <workflow_name> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· interface_name: represents the name of the interface as it appears in the Node Type definition for the Node Type (name) that is declared as the value for on the substitution_mappings’ “node_type” key. Or the name of a new management interface to add to the generated type.
· operation_name: represents the name of the operation as it appears in the interface type definition.
· workflow_name: represents the name of a workflow of the template to map to the specified operation.
· Declarative workflow generation will be applied by the TOSCA orchestrator after the service template have been substituted. Unless one of the normative operations of the standard interface is mapped through an interface mapping. In that case the declarative workflow generation will consider the substitution node as any other node calling the create, configure and start mapped workflows as if they where single operations.
· Operation implementation being TOSCA workflows the TOSCA orchestrator replace the usual operation_call activity by an inline activity using the specified workflow.
A Group Type defines logical grouping types for nodes, typically for different management purposes. Conceptually, group definitions allow the creation of logical “membership” relationships to nodes in a service template that are not a part of the application’s explicit requirement dependencies in the service template (i.e. those required to actually get the application deployed and running). Instead, such logical membership allows for the introduction of things such as group management and uniform application of policies (i.e. requirements that are also not bound to the application itself) to the group’s members. .
The Group Type is a TOSCA type entity and has the common keynames listed in Section 4.2.5.2 Common keynames in type definitions. In addition, the Group Type has the following recognized keynames:
Keyname |
Mandatory |
Type |
Description |
properties |
no |
map of |
An optional map of property definitions for the Group Type. |
attributes |
no |
map of |
An optional map of attribute definitions for the Group Type. |
members |
no |
list of string |
An optional list of one or more names of Node Types that are valid (allowed) as members of the Group Type. |
Group Types have the following grammar:
derived_from: <parent_group_type_name> version: <version_number> metadata: description: <group_description> properties: attributes: members: [ <list_of_valid_member_types> ] |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· group_type_name: represents the mandatory symbolic name of the Group Type being declared as a string.
· parent_group_type_name: represents the name (string) of the Group Type this Group Type definition derives from (i.e. its “parent” type).
· version_number: represents the optional TOSCA version number for the Group Type.
· group_description: represents the optional description string for the corresponding group_type_name.
· attribute_definitions: represents the optional map of attribute definitions for the Group Type.
· property_definitions: represents the optional map of property definitions for the Group Type.
· list_of_valid_member_types: represents the optional list of TOSCA Node Types that are valid member types for being added to (i.e. members of) the Group Type; if the members keyname is not defined then there are no restrictions to the member types;
– note that the members of a group ultimately resolve to nodes, the types here just restrict which nodes can be defined as members in a group definition.
– A node type is matched if it is the specified type or is derived from the node type
During Group Type derivation the keyname definitions follow these rules:
· properties: existing property definitions may be refined; new property definitions may be added.
· attributes: existing attribute definitions may be refined; new attribute definitions may be added.
· members: if the members keyname is defined in the parent type, each element in this list must either be in the parent type list or derived from an element in the parent type list; if the members keyname is not defined in the parent type then no restrictions are applied to the definition.
The following represents a Group Type definition:
group_types: mycompany.mytypes.groups.placement: description: My company’s group type for placing nodes of type Compute members: [ tosca.nodes.Compute ] |
Collections of Nodes may be defined using a Group. A group definition defines a logical grouping of node templates, typically for management purposes, but is separate from the application’s service template.
The following is the list of recognized keynames for a TOSCA group definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory name of the group type the group definition is based upon. |
|
description |
no |
The optional description for the group definition. |
|
metadata |
no |
Defines a section used to declare additional metadata information. |
|
properties |
no |
map of |
An optional map of property value assignments for the group definition. |
attributes |
no |
map of |
An optional map of attribute value assignments for the group definition. |
members |
no |
list of string |
The optional list of one or more node template names that are members of this group definition. |
Group definitions have one the following grammars:
<group_name>: type: <group_type_name> description: <group_description> metadata: properties: attributes: members: [ <list_of_node_templates> ] |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· group_name: represents the mandatory symbolic name of the group as a string.
· group_type_name: represents the name of the Group Type the definition is based upon.
· group_description: contains an optional description of the group.
· property_assignments: represents the optional map of property assignments for the group definition that provide values for properties defined in its declared Group Type.
· attribute_assigments: represents the optional map of attribute assignments for the group definition that provide values for attributes defined in its declared Group Type.
· list_of_node_templates: contains the mandatory list of one or more node template names or group symbolic names (within the same service template) that are members of this logical group
– if the members keyname was defined (by specifying a list_of_valid_member_types) in the group type of this group then the nodes listed here must be compatible (i.e. be of that type or of type that is derived from) with the node types in the list_of_valid_member_types
The following represents a group definition:
groups: my_app_placement_group: type: tosca.groups.Root description: My application’s logical component grouping for placement members: [ my_web_server, my_sql_database ] |
A Policy Type defines a type of a policy that affects or governs an application or service’s topology at some stage of its lifecycle but is not explicitly part of the topology itself (i.e., it does not prevent the application or service from being deployed or run if it did not exist).
The Policy Type is a TOSCA type entity and has the common keynames listed in Section 4.2.5.2 Common keynames in type definitions. In addition, the Policy Type has the following recognized keynames:
Keyname |
Mandatory |
Type |
Description |
properties |
no |
map of |
An optional map of property definitions for the Policy Type. |
targets
|
no |
list of string |
An optional list of valid Node Types or Group Types the Policy Type can be applied to. |
triggers |
no |
map of trigger definitions |
An optional map of policy triggers for the Policy Type. |
Policy Types have the following grammar:
derived_from: <parent_policy_type_name> version: <version_number> metadata: description: <policy_description> properties: targets: [ <list_of_valid_target_types> ] triggers: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· policy_type_name: represents the mandatory symbolic name of the Policy Type being declared as a string.
· parent_policy_type_name: represents the name (string) of the Policy Type this Policy Type definition derives from (i.e., its “parent” type).
· version_number: represents the optional TOSCA version number for the Policy Type.
· policy_description: represents the optional description string for the corresponding policy_type_name.
· property_definitions: represents the optional map of property definitions for the Policy Type.
· list_of_valid_target_types: represents the optional list of TOSCA types (i.e. Group or Node Types) that are valid targets for this Policy Type; if the targets keyname is not defined then there are no restrictions to the targets’ types.
· trigger_definitions: represents the optional map of trigger definitions for the policy.
During Policy Type derivation the keyname definitions follow these rules:
· properties: existing property definitions may be refined; new property definitions may be added.
· targets: if the targets keyname is defined in the parent type, each element in this list must either be in the parent type list or derived from an element in the parent type list; if the targets keyname is not defined in the parent type then no restrictions are applied to this definition.
· triggers: existing trigger definitions may not be changed; new trigger definitions may be added.
The following represents a Policy Type definition:
policy_types: mycompany.mytypes.policies.placement.Container.Linux: description: My company’s placement policy for linux derived_from: tosca.policies.Root |
A policy definition defines a policy that can be associated with a TOSCA service or top-level entity definition (e.g., group definition, node template, etc.).
The following is the list of recognized keynames for a TOSCA policy definition:
Keyname |
Mandatory |
Type |
Description |
type |
yes |
The mandatory name of the policy type the policy definition is based upon. |
|
description |
no |
The optional description for the policy definition. |
|
metadata |
no |
Defines a section used to declare additional metadata information. |
|
properties |
no |
map of |
An optional map of property value assignments for the policy definition. |
targets
|
no |
list of string |
An optional list of valid Node Templates or Groups the Policy can be applied to. |
triggers |
no |
map of trigger definitions |
An optional map of trigger definitions to invoke when the policy is applied by an orchestrator against the associated TOSCA entity. These triggers apply in addition to the triggers defined in the policy type. |
Policy definitions have one the following grammars:
<policy_name>: type: <policy_type_name> description: <policy_description> metadata: properties: targets: [<list_of_policy_targets>] triggers: <trigger_definitions> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· policy_name: represents the mandatory symbolic name of the policy as a string.
· policy_type_name: represents the name of the policy the definition is based upon.
· policy_description: contains an optional description of the policy.
· property_assignments: represents the optional map of property assignments for the policy definition that provide values for properties defined in its declared Policy Type.
· list_of_policy_targets: represents the optional list of names of node templates or groups that the policy is to applied to.
– if the targets keyname was defined (by specifying a list_of_valid_target_types) in the policy type of this policy then the targets listed here must be compatible (i.e. be of that type or of type that is derived from) with the types (of nodes or groups) in the list_of_valid_target_types.
· trigger_definitions: represents the optional map of trigger definitions for the policy; these triggers apply in addition to the triggers defined in the policy type.
The following represents a policy definition:
policies: - my_compute_placement_policy: type: tosca.policies.placement description: Apply my placement policy to my application’s servers targets: [ my_server_1, my_server_2 ] # remainder of policy definition left off for brevity |
A trigger definition defines the event, condition and action that is used to “trigger” a policy with which it is associated.
The following is the list of recognized keynames for a TOSCA trigger definition:
Keyname |
Mandatory |
Type |
Description |
description |
no |
The optional description string for the trigger. |
|
event |
yes |
The mandatory name of the event that activates the trigger’s action. |
|
condition |
no |
The optional condition that must evaluate to true in order for the trigger’s action to be performed. Note: this is optional since sometimes the event occurrence itself is enough to trigger the action. |
|
action |
yes |
list of activity definition |
The list of sequential activities to be performed when the event is triggered, and the condition is met (i.e., evaluates to true). |
Trigger definitions have the following grammars:
<trigger_name>: description: <trigger_description> event: <event_name> condition: <condition_clause> action: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· trigger_name: represents the mandatory symbolic name of the trigger as a string.
· trigger_description: represents the optional description string for the corresponding trigger_name.
· event_name: represents the mandatory name of an event associated with an interface notification on the identified resource (node). .
· condition_clause: an optional Boolean expression that can be evaluated within the context of the service with which the policy is associated and that must evaluate to true in order for the trigger’s action to be performed. Note that the arguments to the condition clause function can in turn be other TOSCA functions. If no condition clause is specified, the trigger event will always result in the trigger’s action being taken.
· list_of_activity_definition: represents the list of activities that are performed in response to the event if the (optional) condition is met.
An activity defines an operation to be performed in a TOSCA workflow step or in an action body of a policy trigger. Activity definitions can be of the following types:
· Delegate workflow activity definition:
– Defines the name of the delegate workflow and optional input assignments. This activity requires the target to be provided by the orchestrator (no-op node or relationship).
· Set state activity definition:
– Sets the state of a node.
· Call operation activity definition:
– Calls an operation defined on a TOSCA interface of a node, relationship or group. The operation name uses the <interface_name>.<operation_name> notation. Optionally, assignments for the operation inputs can also be provided. If provided, they will override for this operation call the operation inputs assignment in the node template.
· Inline workflow activity definition:
– Inlines another workflow defined in the service (allowing reusability). The definition includes the name of a workflow to be inlined and optional workflow input assignments.
The following is a list of recognized keynames for a delegate activity definition.
Keyname |
Mandatory |
Type |
Description |
delegate |
yes |
string or empty (see grammar below) |
Defines the name of the delegate workflow and optional input assignments. This activity requires the target to be provided by the orchestrator (no-op node or relationship). |
workflow |
no |
string |
The name of the delegate workflow. Mandatory in the extended notation. |
inputs |
no |
map of parameter assignments |
The optional map of input parameter assignments for the delegate workflow. |
A delegate activity definition has the following grammar. The short notation can be used if no input assignments are provided.
- delegate: <delegate_workflow_name> |
- delegate: workflow: <delegate_workflow_name> inputs: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· delegate_workflow_name: represents the name of the workflow of the node provided by the TOSCA orchestrator.
· parameter_assignments: represents the optional map of parameter assignments for passing parameters as inputs to this workflow delegation.
Sets the state of the target node.
The following is a list of recognized keynames for a set state activity definition.
Keyname |
Mandatory |
Type |
Description |
set_state |
yes |
string |
Value of the node state. |
A set state activity definition has the following grammar.
- set_state: <new_node_state> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· new_node_state: represents the state that will be affected to the node once the activity is performed.
This activity is used to call an operation on the target node. Operation input assignments can be optionally provided.
The following is a list of recognized keynames for a call operation activity definition.
Keyname |
Mandatory |
Type |
Description |
call_operation |
yes |
string or empty (see grammar below) |
Defines the opration call. The operation name uses the <interface_name>.<operation_name> notation. Optionally, assignments for the operation inputs can also be provided. If provided, they will override for this operation call the operation inputs assignment in the node template. |
operation |
no |
string |
The name of the operation to call, using the <interface_name>.<operation_name> notation. Mandatory in the extended notation. |
inputs |
no |
map of parameter assignments |
The optional map of input parameter assignments for the called operation. Any provided input assignments will override the operation input assignment in the target node template for this operation call. |
A call operation activity definition has the following grammar. The short notation can be used if no input assignments are provided.
- call_operation: <operation_name> |
- call_operation: operation: <operation_name> inputs: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· operation_name: represents the name of the operation that will be called during the workflow execution. The notation used is <interface_sub_name>.<operation_sub_name>, where interface_sub_name is the interface name and the operation_sub_name is the name of the operation within this interface.
· parameter_assignments: represents the optional map of parameter assignments for passing parameters as inputs to this workflow delegation.
This activity is used to inline a workflow in the activities sequence. The definition includes the name of the inlined workflow and optional input assignments.
The following is a list of recognized keynames for an inline workflow activity definition.
Keyname |
Mandatory |
Type |
Description |
inline |
yes |
string or empty (see grammar below) |
The definition includes the name of a workflow to be inlined and optional workflow input assignments. |
workflow |
no |
string |
The name of the inlined workflow. Mandatory in the extended notation. |
inputs |
no |
map of |
The optional map of input parameter assignments for the inlined workflow. |
An inline workflow activity definition has the following grammar. The short notation can be used if no input assignments are provided.
- inline: <inlined_workflow_name> |
- inline: workflow: <inlined_workflow_name> inputs: |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· inlined_workflow_name: represents the name of the workflow to inline.
· parameter_assignments: represents the optional map of parameter assignments for passing parameters as inputs to this workflow delegation.
The following represents a list of activity definitions (using the short notation):
- delegate: deploy - set_state: started - call_operation: tosca.interfaces.node.lifecycle.Standard.start - inline: my_workflow |
A workflow definition defines an imperative workflow that is associated with a TOSCA service. A workflow definition can either include the steps that make up the workflow, or it can refer to an artifact that expresses the workflow using an external workflow language.
The following is the list of recognized keynames for a TOSCA workflow definition:
Keyname |
Mandatory |
Type |
Description |
description |
no |
The optional description for the workflow definition. |
|
metadata |
no |
Defines a section used to declare additional metadata information. |
|
inputs |
no |
map of |
The optional map of input parameter definitions. |
precondition |
no |
condition clause |
Condition clause that must evaluate to true before the workflow can be processed. |
steps
|
no |
map of step definitions |
An optional map of valid imperative workflow step definitions. |
implementation |
no |
The optional definition of an external workflow definition. This keyname is mutually exclusive with the steps keyname above. |
|
outputs |
no |
map of attribute mappings |
The optional map of attribute mappings that specify workflow output values and their mappings onto attributes of a node or relationship defined in the service. |
Imperative workflow definitions have the following grammar:
<workflow_name>: description: <workflow_description> metadata: inputs: precondition: <condition_clause> steps: implementation: <operation_implementation_definitions> outputs: <attribute_mappings>
|
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· workflow_name:
· workflow_description:
· parameter_definitions:
· condition_clause:
· workflow_steps:
· operation_implementation_definition: represents a full inline definition of an implementation artifact
attribute_mappings: represents the optional map of attribute_mappings that consists of named output values returned by operation implementations (i.e. artifacts) and associated mappings that specify the attribute into which this output value must be stored.
A workflow precondition defines a condition clause that checks if a workflow can be processed or not based on the state of the instances of a TOSCA service deployment. If the condition is not met, the workflow will not be triggered.
<<TO BE PROVIDED>>
A workflow step allows to define one or multiple sequenced activities in a workflow and how they are connected to other steps in the workflow. They are the building blocks of a declarative workflow.
The following is the list of recognized keynames for a TOSCA workflow step definition:
Keyname |
Mandatory |
Type |
Description |
target |
yes |
The target of the step (this can be a node template name, a group name) |
|
target_relationship |
no |
The optional name of a requirement of the target in case the step refers to a relationship rather than a node or group. Note that this is applicable only if the target is a node. |
|
operation_host |
no |
The node on which operations should be executed (for TOSCA call_operation activities). This element is mandatory only for relationships and groups target.
If target is a relationship then operation_host is mandatory and valid_values are SOURCE or TARGET – referring to the relationship source or target node.
If target is a group then operation_host is optional. If not specified the operation will be triggered on every node of the group. If specified the valid_value is a node_type or the name of a node template. |
|
filter |
no |
list of validation clauses |
Filter is a list of validation clauses that allows to provide a filtering logic. |
activities |
yes |
list of activity definition |
The list of sequential activities to be performed in this step. |
on_success |
no |
list of string |
The optional list of step names to be performed after this one has been completed with success (all activities has been correctly processed). |
on_failure |
no |
list of string |
The optional list of step names to be called after this one in case one of the step activity failed. |
Workflow step definitions have the following grammars:
steps: target: <target_name> target_relationship: <target_requirement_name> operation_host: <operation_host_name> filter: - <list_of_condition_clause_definition> activities: - <list_of_activity_definition> on_success: - <target_step_name> on_failure: - <target_step_name> |
In the above grammar, the pseudo values that appear in angle brackets have the following meaning:
· target_name: represents the name of a node template or group in the service.
· target_requirement_name: represents the name of a requirement of the node template (in case target_name refers to a node template.
· operation_host: the node on which the operation should be executed
· list_of_condition_clause_definition: represents a list of condition clause definition.
· list_of_activity_definition: represents a list of activity definition
· target_step_name: represents the name of another step of the workflow.
The get_input function is used to retrieve the values of parameters declared within the inputs section of a TOSCA Service Template.
$get_input: <input_parameter_name> |
or
$get_input: [ <input_parameter_name>, <nested_input_parameter_name_or_index_1>, ..., <nested_input_parameter_name_or_index_n> ] |
Note that the first signature does not conform to the custom function definition, but it does not have to as it is a TOSCA built-in function.
Argument |
Mandatory |
Type |
Description |
<input_parameter_name> |
yes |
The name of the parameter as defined in the inputs section of the service template. |
|
<nested_input_parameter_name_or_index_*> |
no |
Some TOSCA input parameters are complex (i.e., composed as nested structures). These parameters are used to dereference into the names of these nested structures when needed.
Some parameters represent list types. In these cases, an index may be provided to reference a specific entry in the list (as identified by the previous parameter) to return. |
The following snippet shows an example of the simple get_input grammar:
inputs: cpus: type: integer
node_templates: my_server: type: tosca.nodes.Compute capabilities: host: properties: num_cpus: { $get_input: cpus } |
The following template shows an example of the nested get_input grammar. The template expects two input values, each of which has a complex data type. The get_input function is used to retrieve individual fields from the complex input data.
data_types: NetworkInfo: derived_from: tosca.Data.Root properties: name: type: string gateway: type: string
RouterInfo: derived_from: tosca.Data.Root properties: ip: type: string external: type: string
service_template: inputs: management_network: type: NetworkInfo router: type: RouterInfo
node_templates: Bono_Main: type: vRouter.Cisco directives: [ substitutable ] properties: mgmt_net_name: { $get_input: [management_network, name]} mgmt_cp_v4_fixed_ip: { $get_input: [router, ip]} mgmt_cp_gateway_ip: { $get_input: [management_network, gateway]} mgmt_cp_external_ip: { $get_input: [router, external]} requirements: - lan_port: node: host_with_net capability: virtualBind - mgmt_net: mgmt_net |
The get_property function is used to retrieve property values of modelable entities in the representation graph. Note that the get_property function may only retrieve the static values of parameter or property definitions of a TOSCA application as defined in the TOSCA Service Template. The get_attribute function should be used to retrieve values for attribute definitions (or property definitions reflected as attribute definitions) from the representation graph of the TOSCA application (as realized by the TOSCA orchestrator).
$get_property: [ <tosca_traversal_path>, <property_name>, <nested_property_name_or_index_1>, ..., <nested_property_name_or_index_n> ] |
Argument |
Mandatory |
Description |
< tosca_traversal_path > |
yes |
Using the <tosca_traversal_path> we can traverse the representation graph to extract information from a certain node or relationship. We start from a specific node or relationship identified by its symbolic name (or by the SELF keyword representing the node or relationship containing the definition) and then we may further traverse the relationships and nodes of the representation graph (using a variable number of steps) until reaching the desired node or relationship. In the following subsection the specification of the <tosca_traversal_path> is explicated. |
<property_name> |
yes |
The name of the property definition the function will return the value from. |
<nested_property_name_or_index_*> |
no |
Some TOSCA properties are complex (i.e., composed as nested structures). These parameters are used to dereference into the names of these nested structures when needed.
Some properties represent list types. In these cases, an index may be provided to reference a specific entry in the list (as identified by the previous parameter) to return. |
<tosca_traversal_path> ::= <initial_context>, <node_context> |
<initial_context>, <rel_context>
<initial_context> ::= <node_symbolic_name> |
<relationship_symbolic_name> |
SELF
<rel_context> ::= SOURCE, <node_context> |
TARGET, <node_context> |
CAPABILITY |
<empty>
<node_context> ::= RELATIONSHIP, <requirement_name>, <idx_of_out_rel_in_req>, <rel_context> |
CAPABILITY, <capability_name>, RELATIONSHIP, <idx_of_incoming_rel>, <rel_context> |
CAPABILITY, <capability_name> |
<empty>
<idx_of_out_rel_in_req> ::= <integer_index> |
ALL |
<empty>
< idx_of_incoming_rel > ::= <integer_index> |
ALL |
<empty>
The initial context (if we refer to a node or relationship) determines if the next context is a relationship context or a node context. Then, each <node_context> can further resolve to a <rel_context> and vice versa, thus building additional traversal steps. In the end we reach either a node context, a relationship context, or a capability context as presented above.
A <rel_context> can
· further lead to the source node of the current relationship
· further lead to the target node of the current relationship
· end within the target capability of the current relationship
· end within the current relationship via the <empty> resolution
A <node_context> can
· further lead to the relationship with index <idx_of_out_rel_in_req> defined by requirement with symbolic name <requirement_name> of the current node
· further lead to the relationship with index <idx_of_incoming_rel> that has as target the capability with symbolic name <capability_name> of the current node
· end within the capability with symbolic name <capability_name> in the current node
· end within the current node via the <empty> resolution
Note that both the indexes can either be a non-negative integer, the keyword ALL, or missing. If it is a non-negative integer, 0 represents the first index and so on incrementally. If the index is missing, the semantic meaning is that the first index (index with value 0) is used. If it is the keyword ALL, then we return the result for all possible indices (further resolved separately) as a list. If the there are multiple ALL keywords in the definition, then all the results shall be merged into a single list.
We further list the changes from the get_property and get_attribute expression from v1.3 to v2.0:
· Added multi-step traversal of the representation graph
· Added the backward traversal from capabilities to incoming relationships
· Added the target capability of a relationship as a possible traversal
· Added the specification of indexes and allowing traversal of multi-count requirements
· Changed the following syntax to work better in multi-step traversal:
– The initial SOURCE, … becomes SELF, SOURCE, …
– The initial TARGET, … becomes SELF, TARGET, …
The following example shows how to use the get_property function with an actual Node Template name:
node_templates:
mysql_database: type: tosca.nodes.Database properties: name: sql_database1
wordpress: type: tosca.nodes.WebApplication.WordPress ... interfaces: Standard: configure: inputs: wp_db_name: { $get_property: [ mysql_database, name ] } |
The following example shows how to use the get_property function traversing from the relationship to its target node:
relationship_templates: my_connection: type: ConnectsTo interfaces: Configure: inputs: targets_value: { $get_property: [ SELF, TARGET, value ] } |
The following example shows how to use the get_property function using the SELF keyword, and traversing from a wordpress node (via the first relationship of the database_endpoint requirement to the target capability in the target node) and accessing the port property of that capability:
node_templates:
mysql_database: type: tosca.nodes.Database ... capabilities: database_endpoint: properties: port: 3306
wordpress: type: tosca.nodes.WebApplication.WordPress requirements: ... - database_endpoint: mysql_database interfaces: Standard: create: wordpress_install.sh configure: implementation: wordpress_configure.sh inputs: ... wp_db_port: $get_property: - SELF - RELATIONSHIP - database_endpoint - 0 - CAPABILITY - port |
NOTE that in the above example the index 0 is used but can also be omitted with the same semantic meaning.
The following example shows how to use the get_property function to traverse over two requirement relationships, from the wordpress node to its database node and further to its DBMS host to get its admin_credential property:
node_templates:
mysql_database: type: tosca.nodes.Database ... capabilities: database_endpoint: properties: port: 3306
wordpress: type: tosca.nodes.WebApplication.WordPress requirements: ... - database_endpoint: mysql_database interfaces: Standard: create: wordpress_install.sh configure: implementation: wordpress_configure.sh inputs: ... host_dbms_admin_credential: $get_property: - SELF - RELATIONSHIP - database_endpoint - TARGET - RELATIONSHIP - host - TARGET - admin_credential |
TODO: An example of second index (i.e. 1) and index ALL !!!
The get_attribute function is used within a representation graph to obtain attribute values from nodes and relationships that have been created from an application model described in a service template. The nodes or relationships can be referenced by their name as assigned in the service template or relative to the context where they are being invoked.
$get_attribute: [<tosca_traversal_path>, <attribute_name>, <nested_attribute_name_or_index_1>, ..., <nested_attribute_name_or_index_n> ] |
Argument |
Mandatory |
Description |
<tosca_traversal_path> |
yes |
Using the <tosca_traversal_path> we can traverse the representation graph to extract information from a certain node or relationship. We start from a specific node or relationship identified by its symbolic name (or by the SELF keyword representing the node or relationship containing the definition) and then we may further traverse the relationships and nodes of the representation graph (using a variable number of steps) until reaching the desired node or relationship. The specification of the <tosca_traversal_path> is explicated in the get_property section. |
<attribute_name> |
yes |
The name of the attribute definition the function will return the value from. |
<nested_attribute_name_or_index_*> |
no |
Some TOSCA attributes are complex (i.e., composed as nested structures). These parameters are used to dereference into the names of these nested structures when needed.
Some attributes represent list types. In these cases, an index may be provided to reference a specific entry in the list (as identified by the previous parameter) to return. |
The attribute functions are used in the same way as the equivalent Property functions described above. Please see their examples and replace “get_property” with “get_attribute” function name.
The get_artifact function is used to retrieve artifact location between modelable entities defined in the same service template.
$get_artifact: [ <modelable_entity_name>, <artifact_name>, <location>, <remove> ] |
Argument |
Mandatory |
Type |
Description |
<modelable entity name> | SELF | SOURCE | TARGET | HOST |
yes |
The mandatory name of a modelable entity (e.g., Node Template or Relationship Template name) as declared in the service template that contains the property definition the function will return the value from. See section B.1 for valid keywords. |
|
<artifact_name> |
yes |
The name of the artifact definition the function will return the value from. |
|
<location> | LOCAL_FILE |
no |
Location value must be either a valid path e.g. ‘/etc/var/my_file’ or ‘LOCAL_FILE’.
If the value is LOCAL_FILE the orchestrator is responsible for providing a path as the result of the get_artifact call where the artifact file can be accessed. The orchestrator will also remove the artifact from this location at the end of the operation.
If the location is a path specified by the user the orchestrator is responsible to copy the artifact to the specified location. The orchestrator will return the path as the value of the get_artifact function and leave the file here after the execution of the operation. |
|
remove |
no |
Boolean flag to override the orchestrator default behavior so it will remove or not the artifact at the end of the operation execution.
If not specified the removal will depends of the location e.g. removes it in case of ‘LOCAL_FILE’ and keeps it in case of a path.
If true the artifact will be removed by the orchestrator at the end of the operation execution, if false it will not be removed. |
The following example uses a snippet of a WordPress [WordPress] web application to show how to use the get_artifact function with an actual Node Template name:
node_templates:
wordpress: type: tosca.nodes.WebApplication.WordPress ... interfaces: Standard: configure: create: implementation: wordpress_install.sh inputs wp_zip: { $get_artifact: [ SELF, zip ] } artifacts: zip: /data/wordpress.zip |
In such implementation the TOSCA orchestrator may provide the wordpress.zip archive as
· a local URL (example: file://home/user/wordpress.zip) or
· a remote one (example: http://cloudrepo:80/files/wordpress.zip) where some orchestrator may indeed provide some global artifact repository management features.
The following example explains how to force the orchestrator to copy the file locally before calling the operation’s implementation script:
node_templates:
wordpress: type: tosca.nodes.WebApplication.WordPress ... interfaces: Standard: configure: create: implementation: wordpress_install.sh inputs wp_zip: { $get_artifact: [ SELF, zip, LOCAL_FILE] } artifacts: zip: /data/wordpress.zip |
In such implementation the TOSCA orchestrator must provide the wordpress.zip archive as a local path (example: /tmp/wordpress.zip) and will remove it after the operation is completed.
The following example explains how to force the orchestrator to copy the file locally to a specific location before calling the operation’s implementation script:
node_templates:
wordpress: type: tosca.nodes.WebApplication.WordPress ... interfaces: Standard: configure: create: implementation: wordpress_install.sh inputs wp_zip: { $get_artifact: [ SELF, zip, C:/wpdata/wp.zip ] } artifacts: zip: /data/wordpress.zip |
In such implementation the TOSCA orchestrator must provide the wordpress.zip archive as a local path (example: C:/wpdata/wp.zip ) and will let it after the operation is completed.
This function is used as an argument inside validation functions. It returns the value of the property, attribute, or parameter for which the validation clause is defined.
$value: [<nested_value_name_or_index>, ... ] |
Argument |
Mandatory |
Description |
<nested_value_name_or_index> |
no |
Some TOSCA data are complex (i.e., composed as nested structures). These parameters are used to dereference into the names of these nested structures when needed. Some data represent lists. In these cases, an index may be provided to reference a specific entry in the list (as identified by the previous parameter) to return. |
TOSCA includes a number of functions that return Boolean values. These functions are used in validation expressions and in condition clauses in workflow definitions and policy definitions. They are also used as node filters in requirement definitions and requirement templates and as substitution filters in substitution mappings.
The $and function takes two or more Boolean arguments. It evaluates to true if all its arguments evaluate to true. It evaluates to false in all other cases.
$and: [ <boolean_arg1>, <boolean_arg2>, ... <boolean_argn>] |
Note that the evaluation of the arguments in the $and function may stop as soon as a false argument is encountered, and the function may return immediately without evaluating the rest of the arguments.
The $or function takes two or more Boolean arguments. It evaluates to false if all of its arguments evaluate to false. It evaluates to true in all other cases.
$or: [ <boolean_arg1>, <boolean_arg2>, ... <boolean_argn>] |
Note that the evaluation of the arguments in the $or function may stop as soon as a true argument is encountered, and the function may return immediately without evaluating the rest of the arguments.
The $not function takes one Boolean argument. It evaluates to true if its argument evaluates to false and evaluates to false if its argument evaluates to true.
$not: [ <boolean_arg> ] |
The $xor function takes two Boolean arguments. It evaluates to false if both arguments either evaluate to true or both arguments evaluate to false, and evaluates to true otherwise.
$xor: [ <boolean_arg1>, <boolean_arg2> ] |
The following is the list of recognized comparison functions.
· Note that some implementations may fail the evaluation if the arguments are not of the same type.
· Also note that Unicode string comparisons are implementation specific.
· TODO explanation on how versions are compared!!!
The function takes two arguments of any type. It evaluates to true if the arguments are equal (that is in both type and value) and evaluates to false otherwise.
$equal: [ <any_type_arg1>, <any_type_arg2> ] |
The function takes two arguments of integer, float, string, timestamp, version, any scalar type, or their derivations. It evaluates to true if both arguments are of the same type, and if the first argument is greater than the second argument and evaluates to false otherwise.
$greater_than: [ <comparable_type_arg1>, <comparable_type_arg2> ] |
The function takes two arguments of integer, float, string, timestamp, version, any scalar type, or their derivations. It evaluates to true if both arguments are of the same type, and if the first argument is greater than or equal to the second argument and evaluates to false otherwise.
$greater_or_equal: [ <comparable_type_arg1>, <comparable_type_arg2> ] |
The function takes two arguments of integer, float, string, timestamp, version, any scalar type, or their derivations. It evaluates to true if both arguments are of the same type, and if the first argument is less than the second argument and evaluates to false otherwise.
$less_than: [ <comparable_type_arg1>, <comparable_type_arg2> ] |
The function takes two arguments of integer, float, string, timestamp, version, any scalar type, or their derivations. It evaluates to true if both arguments are of the same type, and if the first argument is less than or equal to the second argument and evaluates to false otherwise.
$less_or_equal: [ <comparable_type_arg1>, <comparable_type_arg2> ] |
The function takes two arguments. The first argument is of any type and the second argument is a list with any number of values of any type. It evaluates to true if the first argument is equal to a value in the second argument list and false otherwise.
!!! This function is equivalent to the has_entry function (with reversed arguments). A good candidate to remove!
$valid_values: [ <any_type_arg1>, <any_type_list_arg2> ] |
The function takes two arguments. The first argument is a general string, and the second argument is a string that encodes a regular expression pattern. It evaluates to true if the first argument matches the regular expression pattern represented by the second argument and false otherwise.
$matches: [ <string_type_arg1>, <regex_pattern_arg2> ] |
Future drafts of this specification will detail the use of regular expressions and reference an appropriate standardized grammar.
Note also that if ones means that the whole string is to be matched, the regular expression must start with a caret ^ and end with a $.
!!! Check for new lines and maybe add a third argument – e.g. as in https://www.pcre.org/ !!!
The function takes two arguments. Both arguments are either of type string or list. It evaluates to true if the second argument is a suffix of the first argument. For lists this means that the values of the second list are the last values of the first list in the same order.
$has_suffix: [ <string_or_list_type_arg1>, <string_or_list_type_arg2> ] |
The function takes two arguments. Both arguments are either of type string or list. It evaluates to true if the second argument is a prefix of the first argument. For lists this means that the values of the second list are the first values of the first list in the same order.
$has_prefix: [ <string_or_list_type_arg1>, <string_or_list_type_arg2> ] |
The function takes two arguments. Both arguments are either of type string or list. It evaluates to true if the second argument is contained in the first argument. For strings that means that the second argument is a substring of the first argument. For lists this means that the values of the second list are contained in the first list in an uninterrupted sequence and in the same order.
$contains: [ <string_or_list_type_arg1>, <string_or_list_type_arg2> ] |
The function takes two arguments. The first argument is a list or a map. The second argument is of the type matching the entry_schema of the first argument. It evaluates to true if the second argument is an entry in the first argument. For lists this means that the second argument is a value in the first argument list. For maps this means that the second argument is a value in any of the key-value pairs in the first argument map.
$has_entry: [ <list_or_map_type_arg1>, <any_type_arg2> ] |
The function takes two arguments. The first argument is a map. The second argument is of the type matching the key_schema of the first argument. It evaluates to true if the second argument is a key in any of the key-value pairs in the first argument map.
$has_key: [ <map_type_arg1>, <any_type_arg2> ] |
The function takes two arguments. The first argument is a list or a map. The second argument is a list with the entry_schema matching the entry_schema of the first argument. It evaluates to true if for all entries in the second argument there is an equal value entry in the first argument.
$has_all_entries: [ <list_or_map_type_arg1>, <list_type_arg2> ] |
The function takes two arguments. The first argument is a map. The second argument is a list with the entry_schema matching the key_schema of the first argument. It evaluates to true if for all entries in the second argument there is an equal value key in the first argument.
$has_all_keys: [ <map_type_arg1>, <list_type_arg2> ] |
The function takes two arguments. The first argument is a list or a map. The second argument is a list with the entry_schema matching the entry_schema of the first argument. It evaluates to true if there is an entry in the second argument that is equal to an entry in the first argument.
$has_any_entry: [ <list_or_map_type_arg1>, <list_type_arg2> ] |
The function takes two arguments. The first argument is a map. The second argument is a list with the entry_schema matching the key_schema of the first argument. It evaluates to true if there is an entry in the second argument which is equal to a key in the first argument.
$has_any_key: [ <map_type_arg1>, <list_type_arg2> ] |
The function takes an argument of type string, list, or map. It returns the number of nicode characters in the string, or the numbers of values in the list, or the number of key-values pairs in the map.
$length: [ <string_list_or_map_type_arg> ] |
The concat function takes one or more arguments of either the type string or the type list with the same type of their entry_schema. In the case of strings, it returns a string which is the concatenation of the argument strings. In the case of lists, it returns a list that contains all the entries of all the argument lists. Order is preserved both for strings and lists. This function does not recurse into the entries of the lists.
$concat: [<string_or_list_type_arg1>, … ] |
outputs: description: Concatenate the URL for a server from other template values server_url: value: { $concat: [ 'http://', $get_attribute: [ server, public_address ], ':', $get_attribute: [ server, port ] ] } |
The join function takes either one or two arguments where the first one is of type list of strings and the second (optional) argument is of type string. It returns a string that is the joining of the entries in the first argument while adding an optional delimiter between the strings.
!!! Make an example for concat and join where the differences are clear!!!
$join: [<list_of_strings> ] $join: [<list of strings>, <delimiter> ] |
Argument |
Mandatory |
Type |
Description |
<list of strings> |
yes |
list of string or string value expressions |
A list of one or more strings (or expressions that result in a list of string values) which can be joined together into a single string. |
<delimiter> |
no |
string |
An optional delimiter used to join the string in the provided list. |
outputs: example1: # Result: prefix_1111_suffix value: { $join: [ ["prefix", 1111, "suffix" ], "_" ] } example2: # Result: 9.12.1.10,9.12.1.20 value: { $join: [ { $get_input: my_IPs }, “,” ] } |
The token function is used within a TOSCA service template on a string to parse out (tokenize) substrings separated by one or more token characters within a larger string.
$token: [ <string_with_tokens>, <string_of_token_chars>, <substring_index> ] |
Argument |
Mandatory |
Type |
Description |
string_with_tokens |
yes |
The composite string that contains one or more substrings separated by token characters. |
|
string_of_token_chars |
yes |
The string that contains one or more token characters that separate substrings within the composite string. |
|
substring_index |
yes |
The integer indicates the index of the substring to return from the composite string. Note that the first substring is denoted by using the ‘0’ (zero) integer value. |
outputs: webserver_port: description: the port provided at the end of my server’s endpoint’s IP address value: { token: [ $get_attribute: [ my_server, data_endpoint, ip_address ], ‘:’, 1 ] } |
!!!Note: We should discuss order!!!!
The function takes one or more list arguments, all having the entry schema of the same type. The result is a list that contains all non-duplicate entries from all the argument lists. By non-duplicate is meant that no two entries in the result list are equal.
$union: [ <list_arg1>, … ] |
The union applied to only one list will return a result where all the duplicate entries of the argument list are eliminated. Note also that the order of the elements in the result list is not specified.
The function takes one or more list arguments, all having the entry schema of the same type. The result is a list that contains all entries that can be found in each of the argument lists.
$intersection: [ <list_arg1>, … ] |
The intersection applied to only one list will return a result where all the duplicate entries of the argument list are eliminated. Note also that the order of the elements in the result list is not specified.
The function takes one or more arguments of either integer, float, or scalar type. The result is of the same type as the arguments and its value is the arithmetic sum of the arguments’ values.
$sum: [ <int_float_or_scalar_type_arg1>, < int_float_or_scalar_type_arg2>, … ] |
The function takes two arguments of either integer, float, or scalar type. The result is of the same type as the arguments and its value is the arithmetic subtraction of the second argument value from the first argument value.
$difference: [ <int_float_scalar_type_arg1>, < int_float_scalar_type_arg2> ] |
The function takes either:
· Two arguments where the first argument is of a scalar type and the second argument is of an integer or float type. The result is of the same type as the first argument and its value is the arithmetic product of the first argument value and the second argument value.
· Any number of arguments of type integer or float. If all inputs are of type integer, then the result is of type integer, otherwise it is of type float. The result value is the arithmetic product of all the arguments values.
$product: [ <scalar_type_arg1>, < int_or_float_type_arg2> ] $product: [ <int_or_float_type_arg1>, < int_or_float_type_arg2>, … ] |
The function takes two arguments where the first argument is of an integer, float, or scalar type and the second argument is of an integer or float type. The result is of
· A scalar type if the first argument is a scalar, and its value is the arithmetic division of the first argument value by the second argument value. If necessary, the result might be truncated, as decided by the implementation.
· A float if the first argument is an integer or a float. Note that to transform the float to an integer a round or ceil or floor function must be used.
$quotient: [ <int_float_or_scalar_type_arg1>, < int_or_float_type_arg2> ] |
The function takes two arguments where the first argument is of an integer, or scalar type and the second argument is of an integer. The result is of the same type as the first argument and its value is the remainder of the division to the second argument.
$remainder: [ <int_or_scalar_type_arg1>, < int_type_arg2> ] |
The function takes a float argument. The result is an integer with the closest value to the float argument. Equal value distance is rounded down (e.g. 3.5 is rounded down to 3, while 3.53 is rounded up to 4).
$round: [ <float_type_arg> ] |
The function takes a float argument. The result is an integer with the closest value that is less or equal to the value of the float argument.
$floor: [ <float_type_arg> ] |
The function takes a float argument. The result is an integer with the closest value that is greater or equal to the value of the float argument.
$ceil: [ <float_type_arg> ] |
This section defines the metadata of a cloud service archive as well as its overall structure. Except for the examples, this section is normative.
A CSAR is a zip file where TOSCA definitions along with all accompanying artifacts (e.g. scripts, binaries, configuration files) can be packaged together. The zip file format shall conform to the Document Container File format as defined in the ISO/IEC 21320-1 "Document Container File — Part 1: Core" standard [ISO-IEC-21320-1]. A CSAR zip file MUST contain one of the following:
· A TOSCA.meta metadata file that provides entry information for a TOSCA orchestrator processing the CSAR file. The TOSCA.meta file may be located either at the root of the archive or inside a TOSCA-Metadata directory (the directory being at the root of the archive). The CSAR may contain only one TOSCA.meta file.
· a yaml (.yml or .yaml) file at the root of the archive, the yaml file being a valid tosca definition template.
The CSAR file MAY contain other directories and files with arbitrary names and contents.
A TOSCA meta file consists of name/value pairs. The name-part of a name/value pair is followed by a colon, followed by a blank, followed by the value-part of the name/value pair. The name MUST NOT contain a colon. Values that represent binary data MUST be base64 encoded. Values that extend beyond one line can be spread over multiple lines if each subsequent line starts with at least one space. Such spaces are then collapsed when the value string is read.
<name>: <value> |
Each name/value pair is in a separate line. A list of related name/value pairs, i.e. a list of consecutive name/value pairs is called a block. Blocks are separated by an empty line. The first block, called block_0, contains metadata about the CSAR itself and is further defined below. Other blocks may be used to represent custom generic metadata or metadata pertaining to files in the CSAR. A TOSCA.meta file is only required to include block_0. The structure of block_0 in the TOSCA meta file is as follows:
CSAR-Version: digit.digit Created-By: string Entry-Definitions: string Other-Definitions: string |
he name/value pairs are as follows:
· CSAR-Version: This is the version number of the CSAR specification. It defines the structure of the CSAR and the format of the TOSCA.meta file. The value MUST be “2.0” for this version of the CSAR specification.
· Created-By: The person or organization that created the CSAR.
· Entry-Definitions: This references the TOSCA definitions file that SHOULD be used as entry point for processing the contents of the CSAR (e.g. the main TOSCA service template).
· Other-Definitions: This references an unambiguous set of files containing substitution templates that can be used to implement nodes defined in the main template (i.e. the file declared in Entry-Definitions). Thus, all the service templates defined in files listed under the Other-Definitions key are to be used only as substitution templates, and not as standalone services. If such a service template cannot act as a substitution template, it will be ignored by the orchestrator. The value of the Other-Definitions key is a string containing a list of filenames (relative to the root of the CSAR archive) delimited by a blank space. If the filenames contain blank spaces, the filename should be enclosed by double quotation marks (“)
Note that any further TOSCA definitions files required by the definitions specified by Entry-Definitions or Other-Definitions can be found by a TOSCA orchestrator by processing respective imports statements. Note also that artifact files (e.g. scripts, binaries, configuration files) used by the TOSCA definitions and included in the CSAR are fully described and referred via relative path names in artifact definitions in the respective TOSCA definitions files contained in the CSAR.
Users can populate other blocks than block_0 in the TOSCA.meta file with custom name/value pairs that follow the entry syntax defined above and have names that are different from the normative keynames (e.g. CSAR-Version, Created-By, Entry-Definitions, Other-Definitions). These custom name/value pairs are outside the scope of the TOSCA specification.Nevertheless, future versions of the TOSCA specification may add definitions of new keynames to be used in the TOSCA.meta file. In case of a keyname collision (with a custom keyname) the TOSCA specification definitions take precedence.
To minimize such keyname collisions the specification reserves the use of keynames starting with TOSCA and tosca. It is recommended as a good practice to use a specific prefix (e.g. identifying the organization, scope, etc.) when using custom keynames.
The following listing represents a valid TOSCA.meta file according to this TOSCA specification.
CSAR-Version: 2.0 Created-By: OASIS TOSCA TC Entry-Definitions: tosca_elk.yaml Other-Definitions: definitions/tosca_moose.yaml definitions/tosca_deer.yaml |
This TOSCA.meta file indicates its structure (as well as the overall CSAR structure) by means of the CSAR-Version keyname with value 2.0. The Entry-Definitions keyname points to a TOSCA definitions YAML file with the name tosca_elk.yaml which is contained in the root of the CSAR file. Additionally, it specifies that substitution templates can be found in the files tosca_moose.yaml and tosca_deer.yaml found in the directory called definitions in the root of the CSAR file.
In case the archive doesn’t contains a TOSCA.meta file the archive is required to contains a single YAML file at the root of the archive (other templates may exist in sub-directories).
TOSCA processors should recognize this file as being the CSAR Entry-Definitions file. The CSAR-Version is inferred from the tosca_definitions_version keyname in the Entry-Definitions file. For tosca_definitions_version: tosca_2_0 and onwards, the corresponding CSAR-version is 2.0 unless further defined.
Note that in a CSAR without TOSCA-metadata it is not possible to unambiguously include definitions for substitution templates as we can have only one service template defined in a yaml file.
The following represents a valid TOSCA template file acting as the CSAR Entry-Definitions file in an archive without TOSCA-Metadata directory.
tosca_definitions_version: tosca_2_0
metadata: template_name: my_template template_author: OASIS TOSCA TC template_version: 1.0 |
(Note: OASIS strongly recommends that Technical Committees consider issues that could affect security when implementing their specification and document them for implementers and adopters. For some purposes, you may find it required, e.g. if you apply for IANA registration.
While it may not be immediately obvious how your specification might make systems vulnerable to attack, most specifications, because they involve communications between systems, message formats, or system settings, open potential channels for exploit. For example, IETF [RFC3552] lists “eavesdropping, replay, message insertion, deletion, modification, and man-in-the-middle” as well as potential denial of service attacks as threats that must be considered and, if appropriate, addressed in IETF RFCs.
In addition to considering and describing foreseeable risks, this section should include guidance on how implementers and adopters can protect against these risks.
We encourage editors and TC members concerned with this subject to read Guidelines for Writing RFC Text on Security Considerations, IETF [RFC3552], for more information.)
The implementations subject to conformance are those introduced in Section 11.3 “Implementations”. They are listed here for convenience:
· TOSCA YAML service template
· TOSCA processor
· TOSCA orchestrator (also called orchestration engine)
· TOSCA generator
· TOSCA archive
A document conforms to this specification as TOSCA YAML service template if it satisfies all the statements below:
1. It is valid according to the grammar, rules and requirements defined in section 3 “TOSCA definitions in YAML”.
2. When using functions defined in section 4 “TOSCA functions”, it is valid according to the grammar specified for these functions.
3. When using or referring to data types, artifact types, capability types, interface types, node types, relationship types, group types, policy types defined in section 5 “TOSCA normative type definitions”, it is valid according to the definitions given in section 5.
A processor or program conforms to this specification as TOSCA processor if it satisfies all the statements below:
1. It can parse and recognize the elements of any conforming TOSCA YAML service template, and generates errors for those documents that fail to conform as TOSCA YAML service template while clearly intending to.
2. It implements the requirements and semantics associated with the definitions and grammar in section 3 “TOSCA definitions in YAML”, including those listed in the “additional requirements” subsections.
3. It resolves the imports, either explicit or implicit, as described in section 3 “TOSCA definitions in YAML”.
4. It generates errors as required in error cases described in sections 3.1 (TOSCA Namespace URI and alias), 3.2 (Parameter and property type) and 3.6 (Type-specific definitions).
5. It normalizes string values as described in section 5.4.9.3 (Additional Requirements)
A processor or program conforms to this specification as TOSCA orchestrator if it satisfies all the statements below:
1. It is conforming as a TOSCA Processor as defined in conformance clause 2: TOSCA Processor.
2. It can process all types of artifact described in section 5.3 “Artifact types” according to the rules and grammars in this section.
3. It can process TOSCA archives as intended in section 6 “TOSCA Cloud Service Archive (CSAR) format” and other related normative sections.
4. It can understand and process the functions defined in section 4 “TOSCA functions” according to their rules and semantics.
5. It can understand and process the normative type definitions according to their semantics and requirements as described in section 5 “TOSCA normative type definitions”.
6. It can understand and process the networking types and semantics defined in section 7 “TOSCA Networking”.
7. It generates errors as required in error cases described in sections 2.10 (Using node template substitution for chaining subsystems), 5.4 (Capabilities Types) and 5.7 (Interface Types).).
A processor or program conforms to this specification as TOSCA generator if it satisfies at least one of the statements below:
1. When requested to generate a TOSCA service template, it always produces a conforming TOSCA service template, as defined in Clause 1: TOSCA YAML service template,
2. When requested to generate a TOSCA archive, it always produces a conforming TOSCA archive, as defined in Clause 5: TOSCA archive.
A package artifact conforms to this specification as TOSCA archive if it satisfies all the statements below:
1. It is valid according to the structure and rules defined in section 6 “TOSCA Cloud Service Archive (CSAR) format”.
The following individuals have participated in the creation of this specification and are gratefully acknowledged:
Participants:
Adam Souzis (adam@souzis.com)
Alex Vul (alex.vul@intel.com), Intel
Anatoly Katzman (anatoly.katzman@att.com), AT&T
Arturo Martin De Nicolas (arturo.martin-de-nicolas@ericsson.com), Ericsson
Avi Vachnis (avi.vachnis@alcatel-lucent.com), Alcatel-Lucent
Calin Curescu (calin.curescu@ericsson.com), Ericsson
Chris Lauwers (lauwers@ubicity.com)
Claude Noshpitz (claude.noshpitz@att.com), AT&T
Derek Palma (dpalma@vnomic.com), Vnomic
Dmytro Gassanov (dmytro.gassanov@netcracker.com), NetCracker
Frank Leymann (Frank.Leymann@informatik.uni-stuttgart.de), Univ. of Stuttgart
Gábor Marton (gabor.marton@nokia.com), Nokia
Gerd Breiter (gbreiter@de.ibm.com), IBM
Hemal Surti (hsurti@cisco.com), Cisco
Ifat Afek (ifat.afek@alcatel-lucent.com), Alcatel-Lucent
Idan Moyal, (idan@gigaspaces.com), Gigaspaces
Jacques Durand (jdurand@us.fujitsu.com), Fujitsu
Jin Qin, (chin.qinjin@huawei.com), Huawei
Jeremy Hess, (jeremy@gigaspaces.com), Gigaspaces
John Crandall, (mailto:jcrandal@brocade.com), Brocade
Juergen Meynert (juergen.meynert@ts.fujitsu.com), Fujitsu
Kapil Thangavelu (kapil.thangavelu@canonical.com), Canonical
Karsten Beins (karsten.beins@ts.fujitsu.com), Fujitsu
Kevin Wilson (kevin.l.wilson@hp.com), HP
Krishna Raman (kraman@redhat.com), Red Hat
Luc Boutier (luc.boutier@fastconnect.fr), FastConnect
Luca Gioppo, (luca.gioppo@csi.it), CSI-Piemonte
Matej Artač, (matej.artac@xlab.si), XLAB
Matt Rutkowski (mrutkows@us.ibm.com), IBM
Moshe Elisha (moshe.elisha@alcatel-lucent.com), Alcatel-Lucent
Nate Finch (nate.finch@canonical.com), Canonical
Nikunj Nemani (nnemani@vmware.com), Wmware
Peter Bruun (peter-michael.bruun@hpe.com), Hewlett Packard Enterprise
Philippe Merle (philippe.merle@inria.fr), Inria
Priya TG (priya.g@netcracker.com) NetCracker
Richard Probst (richard.probst@sap.com), SAP AG
Sahdev Zala (spzala@us.ibm.com), IBM
Shitao li (lishitao@huawei.com), Huawei
Simeon Monov (sdmonov@us.ibm.com), IBM
Sivan Barzily (sivan@gigaspaces.com), Gigaspaces
Sridhar Ramaswamy (sramasw@brocade.com), Brocade
Stephane Maes (stephane.maes@hp.com), HP
Steve Baillargeon (steve.baillargeon@ericsson.com), Ericsson
Tal Liron (tliron@redhat.com)
Thinh Nguyenphu (thinh.nguyenphu@nokia.com), Nokia
Thomas Spatzier (thomas.spatzier@de.ibm.com), IBM
Ton Ngo (ton@us.ibm.com), IBM
Travis Tripp (travis.tripp@hp.com), HP
Vahid Hashemian (vahidhashemian@us.ibm.com), IBM
Wayne Witzel (wayne.witzel@canonical.com), Canonical
Yaron Parasol (yaronpa@gigaspaces.com), Gigaspaces
Revision |
Date |
Editor |
Changes Made |
WD01, Rev01 |
2019-04-01 |
Chris Lauwers |
Initial WD01, Revision 01 baseline for TOSCA v2.0 |
WD01, Rev02 |
2019-04-22 |
Chris Lauwers |
Split of introductory chapters into the Introduction to TOSCA Version 2.0 document. |
WD01, Rev03 |
2019-05-08 |
Calin Curescu |
Incorporate fixes from latest v1.3 specification |
WD01, Rev04 |
2019-05-10 |
Chris Lauwers |
Fix syntax of schema constraint examples (Sections 5.3.2 and 5.3.4) |
WD01, Rev05 |
2019-08-30 |
Chris Lauwers |
Cleanup formatting. No content changes. |
WD01, Rev06 |
2019-08-30 |
Chris Lauwers |
· Remove 3.6.20.3 since it is no longer relevant. · Separate out new Operation Assignment section 3.8.3 from the original Operation Definition section 3.6.17 · Separate out new Notification Assignment section 3.8.4 from the original Notification Definition section 3.6.19 · Separate out new Interface Assignment section 3.8.5 from the original Interface Definition section 3.6.20 · Update the Interface Type definitions in section 5.8 to show the (now mandatory) ‘operations’ keyname. · Remove erroneous interface definition in tosca.groups.Root type (section 5.10.1) · Added ‘description’ keyname to Requirement definition (section 3.7.3) |
WD01, Rev07 |
2019-09-08 |
Calin Curescu |
· Added the “value” keyname to property definition (Section 3.6.10 Property Definition), · Made the difference between outgoing and incoming parameters in the parameter definition (Section 3.6.14 Parameter definition) · Added the “mapping” keyname to the parameter definition, for mapping the incoming parameter to an attribute (Section 3.6.14 Parameter definition) · Changed the wrong usage of “property definitions” and “property assignments” instead of “parameter definitions” and “parameter assignments” throughout the document. For example, a larger impact can be seen in the definition of the get_input function (Section 4.4.1 get_input). · Changed Section “3.6.16 Operation implementation definition” to include notification implementation definition (Section 3.6.16 Operation implementation definition and notification implementation definition). · Deleted Section “3.6.18 Notification implementation definition” since it was redundant and all relevant information has been transferred to Section “3.6.16 Operation implementation definition and notification implementation definition”. The “Notification definition” section becomes the new Section 3.6.18. · Added operation assignment rules to the operation assignment section (Section 3.8.3 Operation Assignment). · Added notification assignment rules to the notification assignment section (Section 3.8.4 Notification assignment). · Added interface assignment rules to the interface assignment section (Section 3.8.5 Interface assignment). · Changed “interface definitions” with “interface assignments” in the node template specification, given that we have split interface assignments from interface definitions (Section 3.8.6 Node Template) · Changed “interface definitions” with “interface assignments” in the relationship template specification, given that we have split interface assignments from interface definitions (Section 3.8.7 Relationship Template) |
WD01, Rev08 |
2019-09-30 |
Chris Lauwers |
· Fix error in TimeInterval example (Section 5.3.7.3.1) |
WD01, Rev09 |
2020-02-20 |
Chris Lauwers |
· Move normative type definitions to the “Intro to TOSCA” document · Move non-normative type definitions to the “Intro to TOSCA” document · Move “CSAR” specification from the “intro to TOSCA” document into this document |
WD01, Rev10 |
2020-04-15 |
Calin Curescu |
· Reorganized sections into a new layout (starting with the main concepts): · 3.5 -> 3.1; 3.10 -> 3.2.1; 3.1 -> 3.2.2.1; 3.2 -> 3.2.2.2; 3.6.8 -> 3.2.3.1; 3.6.6 -> 3.2.3.2; 3.6.1 -> 3.2.4.1; 3.6.2 -> 3.2.4.2; 3.7.1 -> 3.2.5.2; 3.9 -> 3.2.6; 3.7.9 -> 3.3.1; 3.8.6 -> 3.3.2; 3.7.10 -> 3.3.3; 3.8.7 -> 3.3.4; 3.7.7 -> 3.3.5.1; 3.7.2 -> 3.3.5.2; 3.8.1 -> 3.3.5.3; 3.7.8 -> 3.3.5.4; 3.7.3 -> 3.3.5.5; 3.8.2 -> 3.3.5.6; 3.6.5 -> 3.3.5.7; 3.6.4 -> 3.3.5.8; 3.7.5 -> 3.3.6.1; 3.6.19 -> 3.3.6.2; 3.8.5 -> 3.3.6.3; 3.6.17 -> 3.3.6.4; 3.8.3 -> 3.3.6.5; 3.6.18 -> 3.3.6.6; 3.8.4 -> 3.3.6.7; 3.6.16 -> 3.3.6.8; 3.7.4 -> 3.3.7.1; 3.6.7 -> 3.3.7.2; 3.3 -> 3.4.1; 3.7.6 -> 3.4.2; 3.6.9 -> 3.4.3; 3.6.3 -> 3.4.4; 3.6.10 -> 3.4.5; 3.6.11 -> 3.4.6; 3.6.12 -> 3.4.7; 3.6.13 -> 3.4.8; 3.6.14 -> 3.4.9; 3.8.16 -> 3.5.1; 3.8.11 -> 3.5.2; 3.8.12 -> 3.5.3; 3.8.13 -> 3.5.4; 3.8.14 -> 3.5.5; 3.8.15 -> 3.5.6; 3.7.11 -> 3.6.1; 3.8.8 -> 3.6.2; 3.7.12 -> 3.6.3; 3.8.9 -> 3.6.4; 3.6.21 -> 3.6.5; 3.6.20 -> 3.6.6; 3.6.24 -> 3.6.7; 3.6.23 -> 3.6.8; 3.6.22 -> 3.6.9; 3.8.10 -> 3.7.1; 3.6.25 -> 3.7.2; 3.6.26 -> 3.7.3 |
WD02, Rev01 |
2020-04-23 |
Calin Curescu |
· Added Section 3.1.2 Modeling definitions and reuse · Added Section 3.1.3 Goal of the derivation and refinement rules · Added Section 3.2.5 Type definitions · Added Section 3.2.5.1 General derivation and refinement rules · Reworked and simplified Section 3.2.5.2 as describing common keynames that apply to all TOSCA entity types. Added derivation rules for the common keynames in TOSCA entity types (Section 3.2.5.2.3 Derivation rules). · Added derivation rules for the following TOSCA entity types: node, relationship, capability, interface, and data types in their specific sections. The new sub-sections are named “Derivation rules”. · Added refinement rules for entitiy definitions contained in types undergoing derivations. Refinement rules for the following entity definitions: capability, requirement, interface, operation, notification, schema, property, attribute, and parameter definitions have been added in their specific sections. The new sub-sections are named “Refinement rules”. · Explained that definitions for the properties, attributes and valid_source_types in a capability definition are refinements of the definitions in the capability type (Section 3.3.5.2. Capability definition). · Changed the occurrences keyname in a capability assignment from a range of integer to an integer, to correct the wrong specification in TOSCA v1.3 (Section 3.3.5.3. Capability assignment). · Added the possibility to have provide a symbolic name of a Capability definition within a target Node Type that can fulfill the requirement in the Requirement definition (in addition to the Capability Type) (Section 3.3.5.5. Requirement definition). · Added the possibility to provide a node_filter also in the Requirement definition (this node filter is applied in addition to the node filter defined in the Requirement assignment) (Section 3.3.5.5. Requirement definition). · Explained that the specification supports providing several requirement assignments with the same symbolic name that represent subsets of the occurrences specified in the Requirement definition (Section 3.3.5.6. Requirement assignment). · Changed the occurrences keyname in a requirement assignment from a range of integer to an integer, to correct the wrong specification in TOSCA v1.3 (Section 3.3.5.6. Requirement assignment). · Explained that property definitions may not be added to data types derived_from TOSCA primitive types (Section 3.4.2 Data Type). · Added the rule for a map key definition that its type must be originally derived from string. This is due to fact that in many YAML/TOSCA parsers it is hard to process keys that are not strings, and the added benefit of non-string keys is minimal (Section 3.4.3 Schema definition). · Explained that the default value is irrelevant for properties and parameters that are not required (i.e. where the keyname required is “false”) as they will stay undefined (Section 3.4.5 Property definition and Section 3.4.9 Parameter definition). · A value definition “fixes” the property, that is it cannot be further refined (in a type) or even assigned in (in a template) (Section 3.4.5 Property definition and Section 3.4.6 Property assignment). · Added metadata keyname to attribute definitions (Section 3.4.7 Attribute definition). · Explained that parameter can be of two different kinds: outgoing parameters and incoming parameters, and this depends on the context they are defined in, and steers if these parameters will have a value assigned or will have a mapping to an attribute assigned (Section 3.4.9 Parameter definition). · A value or mapping definition “fixes” the parameter, that is it cannot be further refined (in a type) or even assigned in (in a template) (Section 3.4.9 Parameter definition and 3.4.10 Parameter assignment). |
WD02, Rev02 |
2020-05-07 |
|
· Added derivation rules for the following TOSCA entity types: artifact, group, and policy types) in their specific sections; the new sub-sections are named “Derivation rules”. · Added refinement rules for Artifact definitions (contained in node types undergoing derivations). The new sub-section is named “Refinement rules”. · Added a single-line grammar for defining a value for a property to simplify the value definition for a property (Section 3.4.5 Property definition). · Added the constraints keyname to attribute definitions (Section 3.4.7 Attribute definition). · Added a single-line grammar for parameter definitions when only a parameter to attribute mapping needs to be provided to an incoming parameter (Section 3.4.9 Parameter definition). · Added explanation that triggers defined in the policy definition are applied in addition to the triggers defined in the policy type (Section 3.6.4 Policy definition). |
WD02, Rev03 |
|
Chris Lauwers |
· Incorporate introductory content from the TOSCA v1.0 document with the goal of removing references to the XML version of the standard and making this a stand-alone document. · Explicitly stated that the default keyname SHALL NOT be defined for properties and parameters that are not required (i.e. where the keyname required is “false”) as they will stay undefined (Section 4.4.5 Property definition and Section 4.4.9 Parameter definition). |
WD02, Rev04 |
2020-06-09 |
Calin Curescu |
· Eliminated some comments that were addressed already. · Eliminated the namespace_uri that was already deprecated in TOSCA v1.3 · Eliminated the credential keyname from the repository definition (Section 4.2.3.2 Repository definition) since it was not very useful in the context and also to eliminate the dependency on an external type simple (Credential – in the simple profile) |
WD02, Rev05 |
2020-06-18 |
Calin Curescu |
· Eliminated the schedule keyname in trigger definitions, it was not relevant and used a complex type from the simple profile (Section 4.6.5 Trigger definition). · Deleted the operation_host keyword from the operation implementation definition since it was connected to a hostedOn relationship type, and this is a type feature and not a grammar feature (Section 4.3.6.8 Operation and notification implementation definition). · Eliminated the HOST from the reserved function keywords since it was connected to a hostedOn relationship type, and this is a type feature and not a grammar feature (Section 5 TOSCA functions). · Eliminated some comments that were addressed already. · Changed the type of description to string in the keyname tables throughout the specification. |
WD02, Rev06 |
2020-06-20 |
Chris Lauwers |
· Update the TOSCA overview diagram to include workflows and policies (Section 3.1) · Update the diagram that explains requirements and capabilities (Section 3.4) · Update the diagram that explains substitution (Section 3.5) |
WD02, Rev07 |
2020-06-22 |
Chris Lauwers |
· Edit the “TOSCA core concepts” section to reflect current status of TOSCA (Section 3) |
WD02, Rev08 |
2020-06-24 |
Thinh Nguyenphu |
· Provide additional detail about the required ZIP format and standards in the CSAR definition (Section 6.1) |
WD03, Rev01 |
2020-07-22 |
Calin Curescu Chris Lauwers |
· Remove numerous comments that have been resolved since they were first introduced. |
WD03, Rev02 |
2020-07-26 |
Chris Lauwers |
· Mark keywords as “mandatory” rather than “required” (to avoid confusion with the “required” keyword in property definitions · Introduce “conditional” as an alternative to “yes” or “no” in the “mandatory” columns of the grammar definition. · Remove “Constraints” columns in grammar definitions. · Clarify that entry_schema is mandatory for collection types. |
WD03, Rev03 |
2020-07-28 |
Tal Liron |
· Introduce clear specification of TOSCA built-in types (Sections 4.4.1, 4.4.2, and 4.4.3) |
WD03, Rev04 |
2020-08-03 |
Chris Lauwers |
· Fix typos · Minor formatting fixes |
WD03, Rev05 |
2020-08-18 |
Tal Liron Chris Lauwers |
· Add description of timestamp type · Move scalar-unit types into the Special Types section (4.4.2) · Remove multiples of “bytes per second” from scalar-unit.bitrate to make all scalar units case insensitive · Remove references to the tosca namespace prefix from the built-in type definitions. |
WD03, Rev06 |
2020-08-31 |
Tal Liron Chris lauwers |
· Introduce the notion of “profiles” · Support “import by profile name” · Simplify “namespaces” |
WD03, Rev07 |
2020-09-06 |
Chris Lauwers Tal Liron |
· Remove obsolete prose about namespace URIs (4.2) · Update the section about “import processing rules” (4.2.3.1) · Introduce new prose about support for namespaces (4.2.3.2) |
WD03, Rev08 |
2020-09-07 |
Calin Curescu |
· Clarify discussion of custom keynames in CSAR (6.2.1) |
WD03, Rev09 |
2020-10-26 |
Chris Lauwers |
· Additional discussion of TOSCA Profiles (section 4.2.2) |
WD03, Rev10 |
2020-10-27 |
Calin Curescu |
· Clarified throughout the specification that the key_schema keyname for maps has the default value as “string”, and that the entry_schema keyname definition is mandatory for lists and maps (sections 4.4.5 Schema definition, 4.4.7 Property definition, 4.4.9 Attribute definition, 4.4.11 Parameter definition, 4.4.4. Data type) |
WD04, Rev01 |
2020-11-19 |
Chris Lauwers |
· New OASIS Logo · Correct broken cross reference (Section 4.3.5.8) |
WD04, Rev02 |
2021-01-25 |
Chris Lauwers |
· Incorporate comments provided as part of external review by Paul Jordan (BT) and Mike Rehder (Amdocs) |
WD04, Rev03 |
2021-05-03 |
Chris Lauwers |
· Introduce new Chapter 4 that describes Operational Model. |
WD04, Rev04 |
2021-06-28 |
Chris Lauwers |
· Slight reorganization of the Operation Model chapter (Chapter 4) |
WD04, Rev05 |
2022-02-15 |
Calin Curescu |
· Modified the capability definition (Section 5.3.5.2 ) and assignment (Section 5.3.5.3) removing the occurrences keyname We also added the scope of relationships to the capability assignment (via directives). · Modified the requirement definition (Section 5.3.5.5 ) and assignment (Section 5.3.5.6) replacing the occurrences keyname with the count_range keyname in the requirements definition, and how the assignment must respect the definition and how an automated assignment is assumed to exist if no assignment is specified. The keyname count replaces the keyname occurrences in the assignment to remove any confusion between their slightly different semantics. We also added the scope of relationships to the requirement assignment (via directives). Finally, we added the optional keyname for a requirement assignment to designate if the assignment is optional or not. · We also added the possibility to specify capacity allocation in a requirement assignment (Section 5.3.5.6) where the target capability properties can act as capacity. · Made the relationship definition conditional, it must be present either in the requirement definition (Section 5.3.5.5 ) or in the requirement assignment (Section 5.3.5.5 ). |
WD04, Rev06 |
2022-06-08 |
Calin Curescu |
· Increased the expressivity of accessing properties and attributes in the representation graph by improving the navigation expression in the get_property and get_attribute functions. The representation graph traversal is handled via a new definition (tosca path), that is common to both and is described in section 6.4.2.2.1 The simplified TOSCA_PATH definition in BNF format. · Added multi-step traversal of the representation graph · Added the backward traversal from capabilities to incoming relationships · Added the target capability of a relationship as a possible traversal · Added the specification of indexes and allowing traversal of multi-count requirements · Examples for get_property have been corrected and extended. · Removed the deprecated get_operation_output function · In relationship types (section 5.3.3) following keynames changed/added: · valid_capability_types replaces valid_target_types · valid_target_node_types - new · valid_source_node_types - new · In capability type (section 5.3.5.1) and definition (section 5.3.5.2) following keynames changed/added: · valid_source_node_types - replaces valid_source_types · valid_relationship_types - new |
WD05, Rev01 |
2022-06-14 |
Chris Lauwers |
· Fix formatting errors and typos. · Remove Section 6.1 about reserved function keywords (replaced with TOSCA Path discussion) · Remove Section 6.2 about reserved environment variables. · Rename topology_template keyword to service_template · Remove reference to TOSCA v1.0 specification (Section 5.2.6.2.8) |
WD05, Rev02 |
2022-06-14 |
Chris Lauwers |
· Remove ‘get_nodes_of_type’ function (Section 6.4) · Remove section about ‘Context-based entity names’ (Section 6.6) · Remove sections about “Metadata keynames” (Section 5.2.1.1.1, Section 5.2.1.3.4, Section 5.2.1.3.5, Section 5.2.1.3.6) · Document new metadata grammar (Section 5.2.1.3.3) · Document short notation for schema definitions (Section 5.4.5.2) |
WD05, Rev03 |
2022-09-28 |
Chris Lauwers Calin Curescu |
· Change default count range to [0, UNBOUNDED] (Section 5.3.5.5) · Clarify semantics of profile keynames in imported TOSCA files (Section 5.2.2.2) · Add section about function syntax (Section 6.1) · Add section about defining user-defined custom functions (Section 6.6) · Update all intrinsic functions with the new dollar sign syntax. |
WD05, Rev04 |
2022-11-21 |
Chris Lauwers |
· Remove Normative Values (Section 5.8). Removal of the Simple Profile has made this section obsolete. · Add Condition functions (Section 6.5) · Update policy trigger syntax to use Boolean expressions. · Update workflow precondition syntax to use Boolean expressions · Move sections about functions and function definitions into the TOSCA Definitions chapter |
WD05, Rev05 |
2022-11-21 |
Chris Lauwers |
· Introduce new syntax for defining validation clauses on data types and property definitions. · Update node filter syntax to use Boolean expressions. |
WD05, Rev06 |
2022-11-28 |
Chris Lauwers |
· Validation syntax examples. |
WD05, Rev07 |
2022-12-14 |
Calin Curescu |
· Added the short string-value form for functions without arguments and changed section Function syntax (Section 5.4.14) accordingly. · Added all the existing comparison operators as Boolean functions, the new Boolean logic functions and the new string, list and map membership Boolean functions (Section 6.2) and set manipulation (section 6.4) and arithmetic functions (Section 6.5). |
WD05, Rev08 |
2023-01-17 |
Chris Lauwers Calin Curescu |
· Cleanup for correctness and consistency. · Additional built-in functions (Section 6) |
WD05, Rev09 |
2023-01-18 |
Chris Lauwers |
· Document the ‘value’ function (Section 6.1.5) |