Refactor client/server & GraphQL workflow mutations

[MetRonnie]

These changes partially address cylc/cylc-uiserver#271

Sibling: cylc/cylc-uiserver#290

• Refactored the message format sent from server to client. Instead of just the raw result of the GraphQL mutation (or whatever request was sent¹), the server now responds with a tuple of (content, error, user)
  • This allows errors to be returned over the ZMQ socket without mixing/confusing with the data content
  • user is included like this instead of adding it to the GraphQL {data: ..., errors: ...} response (the spec does not permit adding extra keys)
  • A NamedTuple called ResponseTuple is used instead of a regular tuple for better clarity and type safety
• RefactoredGraphQL workflow mutation output type. Instead of the sometimes-inconsistent GenericResponse output which could be any object in practice, the output is now a graphene.List of GenericReponses, and GenericResponse has 3 fields: workflowId = graphene.String(), success = graphene.Boolean() and message = graphene.String()
  • This pins down what the expected response should be, which should avoid traceback issues like handling scheduler error cylc-uiserver#271
  • In practice this looks like:

    mutation {
      hold (
        workflows: ["temp4"]
        tasks: ["foo.2"]
      ) {
        results {
          workflowId
          success
          message
        }
      }
    }

    {
      "data": {
        "hold": {
          "results": [
            {
              "workflowId": "rdutta|temp4",
              "success": true,
              "message": "Command queued"
            }
          ]
        }
      }
    }

Requirements check-list

• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• Applied any dependency changes to both setup.py and conda-environment.yml.
• Appropriate tests are included (unit and/or functional).
• Appropriate change log entry included.
• (master branch) I have opened a documentation PR at cylc/cylc-doc/pull/XXXX.

Footnotes

1. The exception to this is that Protobuf results are sent back as-is in bytes format instead of the tuple, because bytes is not JSON-serializable ↩

[dwsutherland]

So looks good.. Few minor comments below..

The main issue I'm having (when trying to run this and the UIS sibling), is getting it working

(even after reinstall of venvs)

Perhaps after a rebase, it would help, as there are breaking changes in this and master (?).

[dwsutherland]

I originally had it graphene.List( but it was deemed unnecessary by reviewers.. I guess it can't be helped with typing..

[MetRonnie]

Yes it's an unfortunate clash. But seeing as typing is widely-used now I think it should take precedence

[MetRonnie]

So looks good.. Few minor comments below..

The main issue I'm having (when trying to run this and the UIS sibling), is getting it working

Sorry, should have mentioned: It's not working from the UI yet as some changes need to be made there. But it's working in GraphiQL.

[MetRonnie]

Not going to be finished by Christmas so bumping to 8.0rc2