docs/microservices/workflow.rst

   1 .. This work is licensed under a Creative Commons Attribution 4.0
   2 .. International License. http://creativecommons.org/licenses/by/4.0
   3 .. Copyright (C) 2019 IBM.
   4
   5 Workflow
   6 ========
   7 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.
   8
   9 A workflow also defines inputs and outputs that will defined the payload contract of the request and response (see Dynamic API)
  10
  11 A workflow can be composed of one or multiple sub-actions to execute.
  12
  13 A CBA package can have as many workflows as needed.
  14
  15
  16 Single action
  17 -------------
  18 The workflow is directly backed by a node_template of type tosca.nodes.Component
  19
  20
  21 Multiple sub-actions
  22 --------------------
  23 The workflow is backed by Directed Graph engine, node_template of type dg-generic, and are imperative workflows.
  24
  25 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.
  26
  27 Below the properties of a workflow:
  28
  29
  30 Workflow Example
  31 ----------------
  32 .. code-block:: json
  33
  34    {
  35      "workflow": {
  36        "resource-assignment": {                                <- workflow-name
  37          "inputs": {
  38            "vnf-id": {                                         <- static inputs
  39              "required": true,
  40              "type": "string"
  41            },
  42            "resource-assignment-properties": {                 <- dynamic inputs
  43              "required": true,
  44              "type": "dt-resource-assignment-properties"
  45            }
  46          },
  47          "steps": {
  48            "call-resource-assignment": {                       <- step-name
  49              "description": "Resource Assignment Workflow",
  50              "target": "resource-assignment-process"           <- node_template targeted by the step
  51            }
  52          },
  53          "outputs": {
  54            "template-properties": {                            <- output
  55              "type": "json",                                   <- complex type
  56              "value": {
  57                "get_attribute": [                              <- uses expression to retrieve attribute from context
  58                  "resource-assignment",
  59                  "assignment-params"
  60                ]
  61              }
  62            }
  63          }
  64        }
  65      }
  66    }
  67
  68
  69 TOSCA definition: http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.2/csd01/TOSCA-Simple-Profile-YAML-v1.2-csd01.html#_Toc494454203