Feed 404 causes internal 500 error when creating a label

[PeterJCLaw]

If you have a config like:

state_machines:
  the_workflow:
    feeds:
      - name: jacquard
        url: http://localhost:1212/<label>
    states:
      - gate: choice
        triggers:
          - event: entry
        exit_condition: true
        next:
          type: context
          path: feeds.jacquard.has_option_b
          default: option_a
          destinations:
            - value: true
              state: option_b

      - gate: option_a
        exit_condition: false

      - gate: option_b
        exit_condition: false

which uses a feed in the exit of the first state, but that feed returns a 404 (likely because it's misconfigured, though that might also be a correct response), then the overall creation request will error with LabelAlreadyExists.

[PeterJCLaw]

Note: I'm using the routemaster_sdk to access routemaster, so it's possible that this is a result of the automatic retries I have configured. If that's the case, then the issue is more likely that routemaster is erroring internally.

[PeterJCLaw]

Update: the LabelAlreadyExists is indeed a result of the retrying I was doing. It looks like the label is indeed created fine, but then the processing of the first gate errors, which results in emitting a 500. I was then seeing an (arguably valid) LabelAlreadyExists from the retries.

I think that in the config outlined above, this also means that the label becomes stuck as nothing will cause the gate to be re-evaluated.

[prophile]

Related: we now roll back the entire transaction correctly on a 500.