Python SDK -- No event received for error occurring in a separate thread

SDKs
1

Hi,

I have noticed that we do not receive events for errors occurring on threads created using threading (Python & Python SDK) within a Flask application (we use the Sentry Flask integration).

import sentry_sdk
sentry_sdk.init(
    dsn="dsn_url"
)

def error_func():
    print([][0])

if __name__ == "__main__":
    import threading
    thread = threading.Thread(target=error_func)
    thread.start()
    while True:
        pass

Would you know if there is any simple way to make the SDK correctly report the error event? I’d rather not have to run a try except within my threads or things like that.

2

Your example runs correctly for me. What are you observing with this example?

3

Hi untitaker,

The issue is that no event is received on Sentry for the exception that occurs on the other thread.

4

Do you see any output at all, such as the traceback of the background thread? FWIW I had to add a time.sleep(0) in your while-loop because the background thread would otherwise be starved in some sense.

And to be clear, which Python version is this?

5

Hi,

Yes, I see a traceback:


Traceback (most recent call last):

File "/Users/Konrad/anaconda3/lib/python3.6/threading.py", line 916, in _bootstrap_inner

self.run()

File "/Users/Konrad/anaconda3/lib/python3.6/threading.py", line 864, in run

self._target(*self._args, **self._kwargs)

File « /path", line 8, in error_func

print([][0])

IndexError: list index out of range```

Using PyCharm.

Python 3.6.3

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6

Hi,

Yes, I see a traceback:


Traceback (most recent call last):

File "/Users/Konrad/anaconda3/lib/python3.6/threading.py", line 916, in _bootstrap_inner

self.run()

File "/Users/Konrad/anaconda3/lib/python3.6/threading.py", line 864, in run

self._target(*self._args, **self._kwargs)

File « /path", line 8, in error_func

print([][0])

IndexError: list index out of range```

Using PyCharm.

Python 3.6.3
7

Please make sure it’s not PyCharm interfering with this by launching e.g. from console. I can’t put more debugging efforts into this as it stands.

Also your attachment went missing. I believe this doesn’t work with reply-by-email.

8

Sorry that was my signature!
I just ran it from console and it doesn’t work: no event received. If I raise an exception in the main thread, I do receive an event.

You receive the event fine when testing on your side?

9

Hmm yes I do.

Could you try this instead of providing a DSN:

init(transport=print)

This just prints out the event to the console instead of sending it. If that doesn’t work something else is broken.

10

Hi untitaker,

Seems like my version of sentry_sdk was not up to date.

I updated and I receive the event now.

I apologise for wasting your time, I should have checked. :frowning:

Thanks a lot for the help.

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