Fix #123 -- init broker configuration before loading other app models

[amureki]

Bug from #123 was introduced in #103 where django_dramatiq started benefitting from AppConfig.ready() functionality.
There was a research done in #100 explaining the underlying issue.

My PR is using the idea from @dnmellen to call DjangoDramatiqConfig.ready() during its models import, so earlier than any other custom models code would be imported.
I was trying to come up with a different way, as this one feels tiny bit "hacky", however could not find anything better.

[amureki]

@Bogdanp hey Bogdan! Would be happy to get your input here. Also, would be great to trigger CI jobs to check the PR.

Best,
Rust

[Bogdanp]

Thanks! This looks reasonable. I’ll take a deeper look this Sunday. I don’t see an option to trigger CI right now. Maybe the workflow isn’t set up to run on PRs (if not, that would also be a good change to make).

[amureki]

Something is odd with locks in test database. Seems flaky to me, but I am not yet familiar enough with the codebase to quickly find out the reason.

django.db.utils.OperationalError: database table is locked: django_dramatiq_task

[Bogdanp]

Looks good, I just had a question about ready.

[Bogdanp]

Can you explain this a little bit? Is this needed because now that we're calling ready from import_models, it's also likely to be called during the regular django app lifecycle? If so, wouldn't it be better to avoid running the code at all the second time it's called? I.e.:

def ready(self):
  if getattr(self, "_is_ready", False):
    return
  super().ready()
  ...
  self._is_ready = True

[amureki]

Yes, the idea is to initialize this code during import_models, and then not to rerun it again. Your note is correct, in this case we don't want anything to be called second time, including super().ready(). I missed it as AppConfig.ready is not doing anything, but good point!

[Bogdanp]

Something is odd with locks in test database. Seems flaky to me, but I am not yet familiar enough with the codebase to quickly find out the reason.

django.db.utils.OperationalError: database table is locked: django_dramatiq_task

Yes, I think those tests have always been a little flaky so I wouldn't worry too much about them at the moment.

[Bogdanp]

Looks good to me. Thanks again!