Adding Modeling Concepts documentation from COnfluence to RDT

Issue-ID: CCSDK-2615
Change-Id: Ib5dfaecc96e8fac1dda07aa6c13aba5ded81efee
Signed-off-by: JakobKrieg <jakob.krieg@bcmsolutions.de>
diff --git a/docs/modelingconcepts/workflow.rst b/docs/modelingconcepts/workflow.rst
new file mode 100644
index 0000000..d9c7dc9
--- /dev/null
+++ b/docs/modelingconcepts/workflow.rst
@@ -0,0 +1,322 @@
+.. This work is a derivative of https://wiki.onap.org/display/DW/Modeling+Concepts#Concepts-100023263 by IBM 
+.. used under Creative Commons Attribution 4.0 International License.
+.. http://creativecommons.org/licenses/by/4.0
+.. Copyright (C) 2020 Deutsche Telekom AG.
+
+.. _workflow:
+
+Workflow
+---------
+
+.. note::
+
+   **Workflow Scope within CDS Framework**
+
+   The workflow is within the scope of the micro provisioning and configuration 
+   management in **controller domain** and does NOT account for the MACRO service orchestration workflow which is covered by the SO Project. 
+
+A workflow defines an overall action to be taken on the service, hence is an 
+entry-point for the run-time execution of the :ref:`CBA Package <cba>`.
+
+A workflow also defines **inputs** and **outputs** that will defined the **payload contract** 
+of the **request** and **response** (see :ref:`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.
+
+.. _workflow_single_action:
+
+Single action
+**************
+
+The workflow is directly backed by a component (see :ref:`node_type` -> Component).
+
+In the example bellow, the target of the workflow's steps resource-assignment is ``resource-assignment`` 
+which actually is the name of the ``node_template`` defined after, of type ``component-resource-resolution``.
+
+`Link to example 
+<https://github.com/onap/ccsdk-cds/blob/master/components/model-catalog/blueprint-model/test-blueprint/golden/Definitions/golden-blueprint.json#L40-L71>`_
+
+
+.. code-block:: json
+   :caption: **Example**
+
+      . . .
+   "topology_template": {
+      "workflows": {
+         "resource-assignment": {
+         "steps": {
+            "resource-assignment": {
+               "description": "Resource Assign Workflow",
+               "target": "resource-assignment"
+               ]
+            }
+         },
+         "inputs": {
+            "resource-assignment-properties": {
+               "description": "Dynamic PropertyDefinition for workflow(resource-assignment).",
+               "required": true,
+               "type": "dt-resource-assignment-properties"
+            }
+         },
+         "outputs": {
+            "meshed-template": {
+               "type": "json",
+               "value": {
+               "get_attribute": [
+                  "resource-assignment",
+                  "assignment-params"
+               ]
+               }
+            }
+         }
+         },
+      "node_templates": {
+         "resource-assignment": {
+         "type": "component-resource-resolution",
+         "interfaces": {
+            "ResourceResolutionComponent": {
+               "operations": {
+               "process": {
+                  "inputs": {
+                     "artifact-prefix-names": [
+                     "vf-module-1"
+                     ]
+                  }
+               }
+               }
+            }
+         },
+         "artifacts": {
+            "vf-module-1-template": {
+               "type": "artifact-template-velocity",
+               "file": "Templates/vf-module-1-template.vtl"
+            },
+            "vf-module-1-mapping": {
+               "type": "artifact-mapping-resource",
+               "file": "Templates/vf-module-1-mapping.json"
+            }
+         }
+         }
+      }
+   . . .
+
+.. _workflow_multiple_actions:
+
+Multiple sub-actions
+**********************
+
+The workflow is backed by a Directed Graph engine, dg-generic (see :ref:`node_type` -> DG, 
+and is an **imperative** workflow.
+
+A DG used as workflow for CDS is composed of multiple execute nodes; each individual 
+execute node refers to an modelled Component (see :ref:`node_type` -> Component) instance.
+
+In the example above, you can see the target of the workflow's steps execute-script is 
+``execute-remote-ansible-process``, which is a node_template of type ``dg_generic``
+
+`Link of example 
+<https://github.com/onap/ccsdk-cds/blob/master/components/model-catalog/blueprint-model/test-blueprint/remote_scripts/Definitions/remote_scripts.json#L184-L204>`_ 
+
+.. code-block:: json
+   :caption: **workflow plan example**
+
+   . . .
+   "topology_template": {
+      "workflows": {
+         "execute-remote-ansible": {
+         "steps": {
+            "execute-script": {
+               "description": "Execute Remote Ansible Script",
+               "target": "execute-remote-ansible-process"
+               ]
+            }
+         },
+         "inputs": {
+            "ip": {
+               "required": false,
+               "type": "string"
+            },
+            "username": {
+               "required": false,
+               "type": "string"
+            },
+            "password": {
+               "required": false,
+               "type": "string"
+            },
+            "execute-remote-ansible-properties": {
+               "description": "Dynamic PropertyDefinition for workflow(execute-remote-ansible).",
+               "required": true,
+               "type": "dt-execute-remote-ansible-properties"
+            }
+         },
+         "outputs": {
+            "ansible-variable-resolution": {
+               "type": "json",
+               "value": {
+               "get_attribute": [
+                  "resolve-ansible-vars",
+                  "assignment-params"
+               ]
+               }
+            },
+            "prepare-environment-logs": {
+               "type": "string",
+               "value": {
+               "get_attribute": [
+                  "execute-remote-ansible",
+                  "prepare-environment-logs"
+               ]
+               }
+            },
+            "execute-command-logs": {
+               "type": "string",
+               "value": {
+               "get_attribute": [
+                  "execute-remote-ansible",
+                  "execute-command-logs"
+               ]
+               }
+            }
+         }
+         }
+      },
+      "node_templates": {
+         "execute-remote-ansible-process": {
+         "type": "dg-generic",
+         "properties": {
+            "content": {
+               "get_artifact": [
+               "SELF",
+               "dg-execute-remote-ansible-process"
+               ]
+            },
+            "dependency-node-templates": [
+               "resolve-ansible-vars",
+               "execute-remote-ansible"
+            ]
+         },
+         "artifacts": {
+            "dg-execute-remote-ansible-process": {
+               "type": "artifact-directed-graph",
+               "file": "Plans/CONFIG_ExecAnsiblePlaybook.xml"
+            }
+         }
+         }
+
+Properties of a workflow
+**************************
+
+.. list-table::
+   :widths: 25 75
+   :header-rows: 1
+
+   * - Property
+     - Description
+   * - workflow-name
+     - Defines the name of the action that can be triggered by external system
+   * - inputs
+     - | They are two types of inputs, the dynamic ones, and the static one.
+       | 
+
+       .. tabs::
+          
+          .. tab:: static
+ 
+             Specified at workflow level
+
+             * can be inputs for the Component(s), see the inputs section of the component of interest.
+             * represent inputs to derived custom logic within scripting
+
+             These will end up under ``${actionName}-request`` section of the payload (see Dynamic API)
+
+          .. tab:: dynamic
+ 
+             Represent the resources defined as input (see :ref:`node_type` -> Source -> Input) 
+             within mapping definition files (see :ref:`artifact_type` -> Mapping).
+
+             The **enrichment process** will (see :ref:`enrichment`)
+
+             * dynamically gather all of them under a data-type, named ``dt-${actionName}-properties``
+             * will add it as a input of the workflow, as follow using this name: ``${actionName}-properties``
+
+             Example for workflow named `resource-assignment`:
+
+             .. code-block:: json
+                :caption: **dynamic input**
+
+                "resource-assignment-properties": {
+                "required": true,
+                "type": "dt-resource-assignment-properties"
+                }
+   * - outputs
+     - | Defines the outputs of the execution; there can be as many output as needed.
+       | Depending on the Component (see :ref:`node_type` -> Component) of use, some attribute might be retrievable.
+
+       .. list-table::
+            :widths: 50 50
+            :header-rows: 1
+
+            * - type
+              - value
+            * - data type (complex / primitive)
+              - value resolvable using :ref:`expression` -> get_attribute
+   * - steps
+     - | Defines the actual step to execute as part of the workflow
+       | 
+       .. list-table::
+          :widths: 25 25 50
+          :header-rows: 1      
+          
+          * - step-name
+            - description
+            - target
+          * - name of the step
+            - step description
+            - | a node_template implementing on of the supported Node Type (see :ref:`node_type` -> DG), 
+                either a Component or a DG
+              | (see :ref:`workflow_single_action` or :ref:`workflow_multiple_actions`)
+
+Example:
+
+.. code-block:: json
+   :caption: **workflow example**
+
+   {
+    "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>`_
+