Celery: Unhanded exception in task_prerun_callback

[tony]

Using celery-batches 0.2.0, celery 4.4.7, python 3.10, redis backend

What happens: Request with missing delivery_info raises error. This bubbles up to sentry, another tool.

Expected behavior: Drop the trace is unless error reporting is enabled on scout-apm.

AttributeError: 'NoneType' object has no attribute 'get'
  File "celery/utils/dispatch/signal.py", line 288, in send
    response = receiver(signal=self, sender=sender, **named)
  File "scout_apm/celery.py", line 60, in task_prerun_callback
    tracked_request.tag("is_eager", delivery_info.get("is_eager", False))

{
args: [
[
<celery_batches.SimpleRequest object at 0x7fbd1f2f9720>, 
<celery_batches.SimpleRequest object at 0x7fcd15dd65e0>, 
<celery_batches.SimpleRequest object at 0x7fad18d6fa30>, 
<celery_batches.SimpleRequest object at 0x7fed14d6e1a0>, 
<celery_batches.SimpleRequest object at 0x7fad13d6e230>
]
], 
kwargs: {}, 
sender: <@task: project.app.jobs.track_happening of project at 0x2faa2c2713f0 (v2 compatible)>, 
signal: <Signal: task_prerun providing_args={'args', 'kwargs', 'task', 'task_id'}>, 
task_id: '684c6b14-4349-42e7-bc8d-4d410bceb1c9'
}

[tim-schilling]

Thanks for the issue Tony. Is this occurring for all tasks that use celery-batches?

[tim-schilling]

@tony Which broker are you using with celery?

[tony]

@tim-schilling

broker: Redis

json serializer for tasks and results.

Thanks for the issue Tony. Is this occurring for all tasks that use celery-batches?

Yes. Also I believe the underlying cause is likely the underlying cause is on my end (celery tasks complete fine)

I can provide app id over email at your request

[tim-schilling]

That's alright. I was curious if it was another broker that may be eating it. I suspect what you have is what we need to do. I'm going to change it over to getattr to match the rest of the function, add a test and some docs.

[tony]

@tim-schilling feel free to close out #732 if your getattr way of doing it supersedes it.

[tony]

@tim-schilling Do you have any updates on this? This is an issue preventing us from enabling scout-apm background tasks on in our app

[tim-schilling]

@tony not currently. I will work on it tonight. Thank you for clarifying its importance.

[tim-schilling]

@tony This has been released in v2.24.2. Thank you for the bug report!

[tony]

@tim-schilling Based on my tests 2.42.2 is working well.

all background tasks collect superbly, including the one that was problematic (that ostensibly skips the delivery_info block)