Worker registration can go wrong if name has been used before

[nhoening]

An RQ worker registering under the name we choose for it, might fail to do that if a previous instance is not yet properly de-registered. E.g. when the old one died and the one starts right away:

  File "/home/seita/.virtualenvs/seita-flexmeasures/lib/python3.8/site-packages/flexmeasures/cli/jobs.py", line 59, in run_worker
    worker.work()
  File "/home/seita/.virtualenvs/seita-flexmeasures/lib/python3.8/site-packages/rq/worker.py", line 561, in work
    self.register_birth()
  File "/home/seita/.virtualenvs/seita-flexmeasures/lib/python3.8/site-packages/rq/worker.py", line 299, in register_birth
    raise ValueError(msg.format(self.name))
ValueError: There exists an active worker named 'RQ worker 4 [Seita]' already

Here is the error in our Sentry.

Maybe we can catch this error and append something to the name.

[nhoening]

I think this was fixed within PR #455, see these lines.