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
   8 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.
   9
  10 A workflow also defines inputs and outputs that will defined the payload contract of the request and response (see Dynamic API)
  11
  12 A workflow can be composed of one or multiple sub-actions to execute.
  13
  14 A CBA package can have as many workflows as needed.
  15
  16 Single action
  17 -------------
  18
  19 The workflow is directly backed by a node_template of type tosca.nodes.Component
  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
  31 Workflow Example
  32 ----------------
  33
  34 ::
  35
  36    {
  37      "workflow": {
  38        "resource-assignment": {                                <- workflow-name
  39          "inputs": {
  40            "vnf-id": {                                         <- static inputs
  41              "required": true,
  42              "type": "string"
  43            },
  44            "resource-assignment-properties": {                    <- dynamic inputs
  45              "required": true,
  46              "type": "dt-resource-assignment-properties"
  47            }
  48          },
  49          "steps": {
  50            "call-resource-assignment": {                       <- step-name
  51              "description": "Resource Assignment Workflow",
  52              "target": "resource-assignment-process"           <- node_template targeted by the step
  53            }
  54          },
  55          "outputs": {
  56            "template-properties": {                            <- output
  57              "type": "json",                                   <- complex type
  58              "value": {
  59                "get_attribute": [                              <- uses expression to retrieve attribute from context
  60                  "resource-assignment",
  61                  "assignment-params"
  62                ]
  63              }
  64            }
  65          }
  66        }
  67      }
  68    }
  69
  70
  71 TOSCA definition: http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.2/csd01/TOSCA-Simple-Profile-YAML-v1.2-csd01.html#_Toc494454203