Dump stacktraces of all active Threads

Question

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

As jitter points out in an earlier answer sys._current_frames() gives you what you need for v2.5+. For the lazy the following code snippet worked for me and may help you:

print >> sys.stderr, "\n*** STACKTRACE - START ***\n"
code = []
for threadId, stack in sys._current_frames().items():
    code.append("\n# ThreadID: %s" % threadId)
    for filename, lineno, name, line in traceback.extract_stack(stack):
        code.append('File: "%s", line %d, in %s' % (filename,
                                                    lineno, name))
        if line:
            code.append("  %s" % (line.strip()))

for line in code:
    print >> sys.stderr, line
print >> sys.stderr, "\n*** STACKTRACE - END ***\n"