How can I tell where my python script is hanging?

Question

So I\'m debugging my python program and have encountered a bug that makes the program hang, as if in an infinite loop. Now, I had a problem with an infinite loop before, but

Answer 1

I wrote a module that prints out threads that hang longer that 10 seconds at one place. hanging_threads.py

Run:

python -m pip install hanging_threads

Add this to your code:

from hanging_threads import start_monitoring
start_monitoring(seconds_frozen=10, test_interval=100)

Here is an example output:

--------------------    Thread 5588     --------------------
  File "C:\python33\lib\threading.py", line 844, in _exitfunc
        t.join()
  File "C:\python33\lib\threading.py", line 743, in join
        self._block.wait()
  File "C:\python33\lib\threading.py", line 184, in wait
        waiter.acquire()

This occurs at the exit of the main thread when you forget to set another thread as daemon.