.. This work is licensed under a Creative Commons Attribution 4.0
.. International License. http://creativecommons.org/licenses/by/4.0
.. Copyright (C) 2019 IBM.

Workflow
========

A workflow defines an overall action to be taken on the service, hence is an entry-point for the run-time execution of the CBA package.

A workflow also defines inputs and outputs that will defined the payload contract of the request and response (see Dynamic API)

A workflow can be composed of one or multiple sub-actions to execute.

A CBA package can have as many workflows as needed.

Single action
-------------

The workflow is directly backed by a node_template of type tosca.nodes.Component

Multiple sub-actions
--------------------
The workflow is backed by Directed Graph engine, node_template of type dg-generic, and are imperative workflows.

A DG used as workflow for CDS is composed of multiple execute nodes; each individual execute node refers to a plugin, that is a node_template of type tosca.nodes.Component.

Below the properties of a workflow:



Workflow Example
----------------

.. code:: json

print("
{
  "workflow": {
    "resource-assignment": {                                <- workflow-name
      "inputs": {
        "vnf-id": {                                         <- static inputs
          "required": true,
          "type": "string"
        },
        "resource-assignment-properties": {                    <- dynamic inputs
          "required": true,
          "type": "dt-resource-assignment-properties"
        }
      },
      "steps": {
        "call-resource-assignment": {                       <- step-name
          "description": "Resource Assignment Workflow",
          "target": "resource-assignment-process"           <- node_template targeted by the step
        }
      },
      "outputs": {
        "template-properties": {                            <- output
          "type": "json",                                   <- complex type
          "value": {
            "get_attribute": [                              <- uses expression to retrieve attribute from context
              "resource-assignment",
              "assignment-params"
            ]
          }
        }
      }
    }
  }
}
")


TOSCA definition: http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.2/csd01/TOSCA-Simple-Profile-YAML-v1.2-csd01.html#_Toc494454203