Terminating a Python program that uses multi-process, multi-threading

akineko akineko at gmail.com
Wed Jan 28 21:46:56 CET 2009

Hello Python experts,

I have a program that uses three processes (invoked by
multiprocessing) and several threads.
The program is terminated when ^C is typed (KeyboardInterrupt).
The main process takes the KeyboardInterrupt Exception and it orderly
shutdown the program.

It works fine in normal situation.

However, KeyboardInterrupt is not accepted when, for example, the
program is stuck somewhere due to error in network. I understand that
the KeyboardInterrupt won't be processed until the program moves out
from an atomic step in a Python program.

Probably this is partly my fault as I use some blocking statements
(without timeout) as they should not block the program in normal

As the program freezes up, I cannot do anything except killing three
processes using kill command.
So, I cannot tell which statement is actually blocking when this
occurs (and there are many suspects).

Is there any good way to deal with this kind of problem?
Killing three processes when it hangs is not a fun thing to do.

Any suggestions will be greatly appreciated.

Best regards,
Aki Niimura

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