Interfaces

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Interfaces enable you to map logical tasks to executable operations.

Declaration

Node Types and Relationships Interface

node_types:
  some_type:
    interfaces:
      interface1:
        op1:
          ...
        op2:
          ...
      interface2:
        ...
relationships:
  some_relationship:
    source_interfaces:
      interface1:
        ...
    target_interfaces:
      interface2:
        ...

Each interface declaration under the different interfaces/source_interfaces/target_interfaces sections is a dictionary of operations.

Node Templates Interface Declaration

node_templates:
  some_node:
    interfaces:
      ...
    relationships:
      - type: ...
        target: ...
        source_interfaces:
          ...
        target_interfaces:
          ...

Operations

Operation Declaration in Node Types and Relationships Interfaces

node_types:
  some_type:
    interfaces:
      interface1:
        op1:
          implementation: ...
          inputs:
            ...
          executor: ...
          max_retries: ...
          retry_interval: ...

Operation Schema

Keyname	Required	Type	Description
`implementation`	yes	string	The script or plugin task name to execute.
`inputs`	no	dict	Schema of inputs to be passed to the implementation as kwargs.
`executor`	no	string	Valid values: `central_deployment_agent`, `host_agent`. See the Plugins Specification for more info.
`max_retries`	no	number	Maximum number of retries for a task. `-1` means infinite retries (Default: `task_retries` in the Cloudify Manager config.yaml file for remote workflows, and `task_retries` workflow configuration for local workflows).
`retry_interval`	no	number	Minimum wait time (in seconds) between task retries (Default: `task_retry_interval` in the Cloudify Manager config.yaml file for remote workflows and `task_retry_interval` workflow configuration for local workflows).
`timeout`	no	number	Number of seconds to wait before the operation is terminated by the orchestrator. A value of `0` (or no value at all, which is the default) means no timeout.
`timeout_recoverable`	no	boolean	If `true` (the default), and a timeout occured, then, the operation will raise a `RecoverableError`, resulting in the operation being retried. Otherwise, a `NonRecoverableError` is raised, ending the execution with a failure.

node_types:

  some_type:
    interfaces:
      interface1:
        op1: plugin_name.path.to.module.task

When mapping an operation to an implementation, if it is not necessary to pass inputs or override the executor, the full mapping structure can be avoided and the implementation can be written directly.

node_types:
  some_type:
    interfaces:
      interface1:
        op1:
          implementation: ...
          inputs:
            input1:
              description: ...
              type: ...
              default: ...
          executor: ...

Operation Input Schema

Keyname	Required	Type	Description
description	no	string	Description for the input.
type	no	string	The required data type of the input. Not specifying a data type means the type can be anything, including a list, an array or a dictionary. Valid types: `string`, `integer`, `float`, `boolean`, `list`, `dict`, `regex` or a custom data type.
default	no	<any>	An optional default value for the input.

Operation Inputs in Node Templates Interfaces Declaration

node_types:
  some_type:
    interfaces:
      interface1:
        op1:
          implementation: plugin_name.path.to.module.task
          inputs:
            input1:
              description: some mandatory input
            input2:
              description: some optional input with default
              default: 1000
          executor: ...

node_templates:
  type: some_type
  some_node:
    interfaces:
      interface1:
        op1:
          inputs:
            input1: mandatory_input_value
            input3: some_additional_input

When an operation in a node template interface is inherited from a node type or a relationship interface:

All inputs that were declared in the operation inputs schema must be provided.
Additional inputs, which were not specified in the operation inputs schema, may also be passed.

Examples

In the following examples, an interface is declared that enables you to:

Configure a master deployment server using a plugin.
Deploy code on the hosts using a plugin.
Verify that the deployment succeeded using a shell script.
Start an application after the deployment is complete.

For the sake of simplicity, relationships are not referred to in these examples.

Configuring Interfaces in Node Types

Configuring the master server:

plugins:
  deployer:
    executor: central_deployment_agent

node_types:
  nodejs_app:
    derived_from: cloudify.nodes.ApplicationModule
    properties:
      ...
    interfaces:
      my_deployment_interface:
        configure:
          implementation: deployer.config_in_master.configure

node_templates:
  nodejs:
    type: nodejs_app

In this example, the following declarations have been made:

Declared a deployer plugin which, by default, executes its operations on Cloudify Manager.
Declared a node type with a my_deployment_interface interface that has a single configure operation that is mapped to the deployer.config_in_master.configure task.
Declared a nodejs node template of type nodejs_app.

Overriding the Executor

In the above example an executor for the deployer plugin has been declared. Cloudify enables you to declare an executor for a single operation, overriding the previous declaration.

plugins:
  deployer:
    executor: central_deployment_agent

node_types:
  nodejs_app:
    derived_from: cloudify.nodes.ApplicationModule
    properties:
      ...
    interfaces:
      my_deployment_interface:
        configure:
          implementation: deployer.config_in_master.configure
        deploy:
          implementation: deployer.deploy_framework.deploy
          executor: host_agent

node_templates:
  vm:
    type: cloudify.openstack.nodes.Server
  nodejs:
    type: nodejs_app

In this example, a deploy operation to our my_deployment_interface interface has been added. Note that its executor attribute is configured to host_agent, which means that even though the deployer plugin is configured to execute operations on the central_deployment_agent, the deploy operation is executed on hosts of the nodejs_app rather than Cloudify Manager.

Declaring an Operation Implementation within the Node

You can specify a full operation definition within a node’s interface, under the node template itself.

plugins:
  deployer:
    executor: central_deployment_agent

node_types:
  nodejs_app:
    derived_from: cloudify.nodes.ApplicationModule
    properties:
      ...
    interfaces:
      my_deployment_interface:
        ...

node_templates:
  vm:
    type: cloudify.openstack.nodes.Server
  nodejs:
    type: nodejs_app
    interfaces:
      my_deployment_interface:
        ...
        start: scripts/start_app.sh

If, for example, the my_deployment_interface is used on more than the nodejs node, while on all other nodes, a start operation is not mapped to anything, you will want to have a start operation specifically for the nodejs node, which will run the application after it is deployed.

A start operation is declared and mapped to execute a script specifically on the nodejs node.

In this way, you can define your interfaces either in node_types or in node_templates, depending on whether you want to reuse the declared interfaces in different nodes or declare them in specific nodes.

Operation Inputs

Operations can specify inputs to be passed to the implementation.

plugins:
  deployer:
    executor: central_deployment_agent

node_types:
  nodejs_app:
    derived_from: cloudify.nodes.ApplicationModule
    properties:
      ...
    interfaces:
      my_deployment_interface:
        configure:
          ...
        deploy:
          implementation: deployer.deploy_framework.deploy
          executor: host_agent
          inputs:
            source:
              description: deployment source
              type: string
              default: git
        verify:
          implementation: scripts/deployment_verifier.py

node_templates:
  vm:
    type: cloudify.openstack.nodes.Server
  nodejs_app:
    type: cloudify.nodes.WebServer
    interfaces:
      my_deployment_interface:
        ...
        start:
          implementation: scripts/start_app.sh
          inputs:
            app: my_web_app
            validate: true

In this example, an input has been added to the deploy operation under the my_deployment_interface interface in the nodejs_app node type, and two inputs added to the start operation in the nodejs node’s interface.

Relationship Interfaces

For information on relationship interfaces see Relationships Specification.