unhandled_exit

unhandled_exit makes the whole process exit if an unhandled exception occours in a thread or in main.

Uses threading.excepthook which is only available in Python 3.8 and later. The automated tests test Python 3.8, 3.9 and 3.10.

Usage

import unhandled_exit
unhandled_exit.activate()

Why

When using Python with threads, an uncaught exception no longer exits the process, but only exits the affected thread.

This can make perfect sense if the application restarts threads as needed, or the threads are disposable.

But if the application does not handle a thread exit, the application can be left running in defunct state.

In this situation I (and some [1] other [2] people) [3]) find it preferable to have the whole process exit with a bang so the service manager can restart it and/or the developer can investigate what went wrong.

API Documentation

activate()

activate() enables the functionality of the unhandled_exit package. After calling activate(), the whole process will exit if an unhandled exception occurs in a thread or in main.

This works by chaining os._exit(1) after threading.excepthook and sys.excepthook.

It is safe to call activate() multiple times. The second and later calls will be no-ops.

deactivate()

deactivate() resets threading.excepthook and sys.excepthook to the values they had before activate().

It is safe to call deactivate() multiple times. The second and later calls will be no-ops.

If threading.excepthook and/or sys.excepthook have been changed between activate() and deactivate(), a warning is printed and this excepthook is left as-is.

Development

Get the code:

git clone https://github.com/rfjakob/unhandled_exit
cd unhandled_exit

Run the Test Suite (needs pip install hatch):

make test

Output should look like this:

python -m compileall -q .
hatch run test
========================== test session starts ===========================
platform linux -- Python 3.10.7, pytest-7.1.3, pluggy-1.0.0 -- /home/jakob/.local/share/hatch/env/virtual/unhandled-exit/PB23ljro/unhandled-exit/bin/python
cachedir: .pytest_cache
rootdir: /home/jakob.donotbackup/code/unhandled_exit
plugins: cov-4.0.0
collected 4 items                                                        

tests/tests.py::test_crash_main PASSED                             [ 25%]
tests/tests.py::test_crash_thread PASSED                           [ 50%]
tests/tests.py::test_crash_single PASSED                           [ 75%]
tests/tests.py::test_nocrash PASSED                                [100%]

=========================== 4 passed in 0.18s ============================

Publish to pypi (needs pip install hatch):

make publish

References

[1] https://stackoverflow.com/questions/49663124/cause-python-to-exit-if-any-thread-has-an-exception

[2] https://stackoverflow.com/questions/57208345/how-to-kill-process-if-thread-encounters-exception

[3] https://stackoverflow.com/questions/71051325/is-there-any-way-to-stop-all-workers-in-a-threadpool-if-any-of-the-worker-raise