Multi step workflow

[antho1404]

Fix #1197

TODO:

• Add multiple tasks to workflows
• Create hash for workflows
• Add workflow hash to execution
• Resolve next steps on workflow based on workflowHash + execution height (length of the chain)

Testing:

Note that the CLI is not yet updated for that so you will need to use the GRPC API directly.

We will create the following workflow:

+------------+      +------------+      +------------+     +------------+
|  ServiceA  |      |  ServiceB  |      |  ServiceC  |     |  ServiceB  |
|   taskX    +----->+   taskY    +----->+   taskZ    +---->+   taskY    |
+------------+      +------------+      +------------+     +------------+

when Result of ServiceA#taskX
  then Call ServiceB#taskY
  then Call ServiceC#taskZ
  then Call ServiceB#taskY

These services are just accumulator that take a message in input and return a message that is the concatenation of the input plus the task executed.

You can find the services here:

ServiceA:

{"name":"serviceA","tasks":[{"inputs":[{"type":"String","key":"message"}],"outputs":[{"type":"String","key":"message"}],"key":"taskX"},{"key":"emits"}],"events":[{"data":[{"type":"String","key":"message"}],"key":"eventX"}],"configuration":{},"hash":"9P49TPmeToJDb2vSLwv3iovz56UWJJinRMhM3TMkEcEw","sid":"serviceA","source":"QmUojyMjo2JUvhktLU4royUBDEsVzU4z1onPovGpVQAFDW"}

ServiceB:

{"name":"serviceB","tasks":[{"inputs":[{"type":"String","key":"message"}],"outputs":[{"type":"String","key":"message"}],"key":"taskY"}],"configuration":{},"hash":"3vZaZD59AUzxMAaRREFFR2XEKvU6mYDVv5UweTgSQF4c","sid":"serviceB","source":"Qmf2e92jNxxmYyjxEFrCBJdCNUS1LKNWet2ZQt3ByEUpAP"}

ServiceC:

{"name":"serviceC","tasks":[{"inputs":[{"type":"String","key":"message"}],"outputs":[{"type":"String","key":"message"}],"key":"taskZ"},{"inputs":[{"type":"String","key":"message"}],"outputs":[{"type":"String","key":"message"}],"key":"taskA"}],"configuration":{},"hash":"EvYgwFjAQpGs19EgoXi4EExJXoH7DL6Fmae4RStQZzt2","sid":"serviceC","source":"QmPuHX3LumnDkrxY3wUR8J2J9xmXGw8yTVy5jf7P24MprN"}

Once these services are created and started you can write the following workflow:

{
  "sid": "workflow",
  "name": "workflow",
  "source": "QmbtKRgiDxB8dChfdRA2Hk7MYtB1yB3dXrnh2msus7Ft8P",
  "workflows": [
    {
      "key": "event",
      "trigger": {
        "type": 1,
        "instanceHash": "88YtHw3iZtjpAeDDUWHsDFg9MLvgircPzCFHxFqJ2ex9",
        "key": "eventX"
      },
      "tasks": [
        {
          "instanceHash": "8qKUdaMPAn35ozeUWVcT9BQ5gHNJYbJJ5rTCWqfnJgpW",
          "taskKey": "taskY"
        },
        {
          "instanceHash": "7sTRCDpWCXYBSVgh7dKKV6pP69PHdYQY8kyBohumEWNu",
          "taskKey": "taskZ"
        }
      ]
    },
    {
      "key": "result",
      "trigger": {
        "type": 2,
        "instanceHash": "88YtHw3iZtjpAeDDUWHsDFg9MLvgircPzCFHxFqJ2ex9",
        "key": "taskX"
      },
      "tasks": [
        {
          "instanceHash": "8qKUdaMPAn35ozeUWVcT9BQ5gHNJYbJJ5rTCWqfnJgpW",
          "taskKey": "taskY"
        },
        {
          "instanceHash": "7sTRCDpWCXYBSVgh7dKKV6pP69PHdYQY8kyBohumEWNu",
          "taskKey": "taskZ"
        }
      ]
    },
    {
      "key": "result-from-other-workflow",
      "trigger": {
        "type": 2,
        "instanceHash": "8qKUdaMPAn35ozeUWVcT9BQ5gHNJYbJJ5rTCWqfnJgpW",
        "key": "taskY"
      },
      "tasks": [
        {
          "instanceHash": "7sTRCDpWCXYBSVgh7dKKV6pP69PHdYQY8kyBohumEWNu",
          "taskKey": "taskZ"
        }
      ]
    }
  ]
}

Where

• 88YtHw3iZtjpAeDDUWHsDFg9MLvgircPzCFHxFqJ2ex9: Hash of instance of serviceA
• 8qKUdaMPAn35ozeUWVcT9BQ5gHNJYbJJ5rTCWqfnJgpW: Hash of instance of serviceB
• 7sTRCDpWCXYBSVgh7dKKV6pP69PHdYQY8kyBohumEWNu: Hash of instance of serviceC

Now if you execute taskX from serviceA all the tasks of the workflow will be triggered.

grpcurl -plaintext \
  -d "{\"instanceHash\":\"88YtHw3iZtjpAeDDUWHsDFg9MLvgircPzCFHxFqJ2ex9\", \"taskKey\":\"taskX\", \"inputs\":{\"message\":\"\"}}" \
  localhost:50052 api.Execution/Create

You can also try with events by calling the emits task from serviceA with no inputs

grpcurl -plaintext \
  -d "{\"instanceHash\":\"88YtHw3iZtjpAeDDUWHsDFg9MLvgircPzCFHxFqJ2ex9\", \"taskKey\":\"emits\", \"inputs\":{}}" \
  localhost:50052 api.Execution/Create

[NicolasMahe]

The workflow should be based on simple yet generic graph definition (nodes and edges).
The engine should check for the graph complexity (only directive and radius of 1).

[NicolasMahe]

should return the error, no?

[NicolasMahe]

As discussed, the calculation of the height bring a few problems mainly when the workflow is circular (or multiple workflow are).
The height could be saved directly in the Execution.
Also, height is only valid for mono-branch workflow, fine for now but big limitation for the future.