Debugging a Python Program that Hangs

[Kevin D. Smith]

I have a fairly large python program that, when a certain combination
of options is used, hangs. I have no idea where it is hanging, so
simply putting in print statements to locate the spot would be quite
difficult. Unfortunately, ctrl-C'ing the program doesn't print a
traceback either. Looking through the python debugger documentation, I
don't see how to run a python program and interactively stopping it
while it is running. Is there a way to stop within a running python
program to see where it is getting hung up?

 

[alex23]

I have a fairly large python program that, when a certain combination
of options is used, hangs.  I have no idea where it is hanging, so
simply putting in print statements to locate the spot would be quite
difficult.  Unfortunately, ctrl-C'ing the program doesn't print a
traceback either.  Looking through the python debugger documentation, I
don't see how to run a python program and interactively stopping it
while it is running.  Is there a way to stop within a running python
program to see where it is getting hung up?

Hey Kevin, long time fan of your films! (I bet you get that a lot...)

The trace module might help you identify where it's getting caught up:

http://www.python.org/doc/2.5.2/lib/trace-cli.html

 

[Stef Mientki]

check winpdb / rpdb2,
cheers,
Stef

Hey Kevin, long time fan of your films! (I bet you get that a lot...)

The trace module might help you identify where it's getting caught up:

http://www.python.org/doc/2.5.2/lib/trace-cli.html

 

[Kay Schluehr]

I have a fairly large python program that, when a certain combination
of options is used, hangs.  I have no idea where it is hanging, so
simply putting in print statements to locate the spot would be quite
difficult.  Unfortunately, ctrl-C'ing the program doesn't print a
traceback either.  Looking through the python debugger documentation, I
don't see how to run a python program and interactively stopping it
while it is running.  Is there a way to stop within a running python
program to see where it is getting hung up?

You might approximate the critical location using exceptions instead
of prints. That's more costly of course because the program has to be
restarted more often but it will serve the same purpose.

 

[Ross Ridge]

I have a fairly large python program that, when a certain combination
of options is used, hangs. I have no idea where it is hanging, so
simply putting in print statements to locate the spot would be quite
difficult. Unfortunately, ctrl-C'ing the program doesn't print a
traceback either.

Have you tried catching the KeyboardInterrupt exception and printing
an exception? Something like:

try:
rest_of_program()
except KeyboardInterrupt:
traceback.print_exc()
raise

Ross Ridge