Dump stacktraces of all active Threads

Question

Hey Guys,

I'm trying to dump a list of all active threads including the current stack of each. I can get a list of all threads using threading.enumerate(), but i can't figure out a way to get to the stack from there.

Background: A Zope/Plone app freaks out from time to time, consuming 100% of cpu and needs to be restarted. I have a feeling it's a loop which doesn't terminate properly, but i cannot reproduce it in the test-environemt for verification. I managed to register a signal handler which can be triggered from the outside, so i can trigger some code as soon as the situation occurs again. If I could dump the stacktrace for all active threads, that would give me a clue what goes wrong. The hole thing runs on python 2.4...

Any ideas on how to trace down situations like these are appreciated :)

Cheers, Chriss

Answer 1

There is an applicable recipe on ASPN. You can use threading.enumerate() to get all the tids, then just call _async_raise() with some suitable exception to force a stack trace.

Answer 2

2.4. Too bad. From Python 2.5 on there is sys._current_frames().

But you could try threadframe. And if the makefile gives you trouble you could try this setup.py for threadframe

Sample output when using threadframe

Answer 3

Use Products.signalstack; it was designed for just this purpose!

Send a USR1 signal to your Zope server and it'll immediately dump stack traces for all threads to the console. It'll do this even if all Zope threads are locked up.