Intermittent Fatal Python error: could not acquire lock for <_io.BufferedWriter name='<stderr>'> at interpreter shutdown, possibly due to daemon threads

SDK intermittently causing fatal errors like this:

[sentry] DEBUG: atexit: got shutdown signal
[sentry] DEBUG: atexit: shutting down client
[sentry] DEBUG: Flushing HTTP transport
[sentry] DEBUG: background worker got flush request
[sentry] DEBUG: background worker flushed
[sentry] DEBUG: Killing HTTP transport
[sentry] DEBUG: background worker got kill request
[sentry] DEBUG: Killing HTTP transport
Fatal Python error: could not acquire lock for <_io.BufferedWriter name='<stderr>'> at interpreter shutdown, possibly due to daemon threads

Thread 0x00007f4debd63700 (most recent call first):
  File "/usr/lib/python3.7/logging/__init__.py", line 1009 in flush
  File "/usr/lib/python3.7/logging/__init__.py", line 1029 in emit
  File "/usr/lib/python3.7/logging/__init__.py", line 894 in handle
  File "/usr/lib/python3.7/logging/__init__.py", line 1586 in callHandlers
  File "/usr/local/lib/python3.7/dist-packages/sentry_sdk/integrations/logging.py", line 85 in sentry_patched_callhandlers
  File "/usr/lib/python3.7/logging/__init__.py", line 1524 in handle
  File "/usr/lib/python3.7/logging/__init__.py", line 1514 in _log
  File "/usr/lib/python3.7/logging/__init__.py", line 1366 in debug
  File "/usr/local/lib/python3.7/dist-packages/sentry_sdk/worker.py", line 78 in kill
  File "/usr/local/lib/python3.7/dist-packages/sentry_sdk/transport.py", line 357 in kill
  File "/usr/local/lib/python3.7/dist-packages/sentry_sdk/transport.py", line 98 in __del__
  File "/usr/local/lib/python3.7/dist-packages/sentry_sdk/worker.py", line 118 in _target
  File "/usr/lib/python3.7/threading.py", line 870 in run
  File "/usr/local/lib/python3.7/dist-packages/sentry_sdk/integrations/threading.py", line 67 in run
  File "/usr/lib/python3.7/threading.py", line 926 in _bootstrap_inner
  File "/usr/lib/python3.7/threading.py", line 890 in _bootstrap

Current thread 0x00007f4df23a7700 (most recent call first):

• Python 3.7.9
• sentry-sdk==0.18.0

[alexanderilyin]

Seems like the problem is coming from sentry_sdk.init( ... debug=True ... ) param, seems that disabling debug helped. I was happening more frequently when reporting transactions/spans and I’m not currently doing that. I don’t have a reproducible case that I can share at the moment due to the intermittent error nature. Another thing that it’s used in a Python CLI app.

[alexanderilyin]

Probably disabling atexit could help.

17:05:21  [sentry] DEBUG: Setting up integrations (with default = True)
17:05:21  [sentry] DEBUG: Setting up previously not enabled integration logging
17:05:21  [sentry] DEBUG: Setting up previously not enabled integration stdlib
17:05:21  [sentry] DEBUG: Setting up previously not enabled integration excepthook
17:05:21  [sentry] DEBUG: Setting up previously not enabled integration dedupe
17:05:21  [sentry] DEBUG: Setting up previously not enabled integration atexit
17:05:21  [sentry] DEBUG: Setting up previously not enabled integration modules
17:05:21  [sentry] DEBUG: Setting up previously not enabled integration argv
17:05:21  [sentry] DEBUG: Setting up previously not enabled integration threading
17:05:21  [sentry] DEBUG: Enabling integration logging
17:05:21  [sentry] DEBUG: Enabling integration stdlib
17:05:21  [sentry] DEBUG: Enabling integration excepthook
17:05:21  [sentry] DEBUG: Enabling integration dedupe
17:05:21  [sentry] DEBUG: Enabling integration atexit
17:05:21  [sentry] DEBUG: Enabling integration modules
17:05:21  [sentry] DEBUG: Enabling integration argv
17:05:21  [sentry] DEBUG: Enabling integration threading