multiprocess-dump-stack.py

import functools
import inspect
from multiprocessing import Process
import os
import signal
import sys
import time
import traceback

# XXX specify # levels to skip, specify the frame you want to start with (in case called from a signal handler)
def print_fancy_stack(output):
    stack = inspect.stack()

    for frame, filename, lineno, function, lines, line_index in stack[2:]:
        output.write('File "{filename}", line {lineno}, in {function}\n  {current_line}\n'.format(
            filename=filename,
            lineno=lineno,
            function=function,
            current_line=lines[line_index].rstrip('\n')))
        if frame.f_locals and function != '<module>':
            output.write('Locals:\n')
            for variable in sorted(frame.f_locals.keys()):
                output.write('\t'.join([variable, repr(frame.f_locals[variable])]) + '\n')

def foo():
    for i in xrange(100000000):
        pass
    print 'done'

def bar():
    foo()

# XXX you get a stack frame in `two`
def handle_signal(output, one, two):
    print_fancy_stack(output)

def baz(read_fd, write_fd):
    os.close(read_fd)
    with os.fdopen(write_fd, 'w') as writer:
        signal.signal(signal.SIGINT, functools.partial(handle_signal, writer))
        signal.signal(signal.SIGTERM, functools.partial(handle_signal, writer))
        bar()

def main():
    read_fd, write_fd = os.pipe()
    worker = Process(target=baz, args=(read_fd, write_fd))
    worker.start()
    os.close(write_fd)
    reader = os.fdopen(read_fd, 'r')
    time.sleep(1)
    os.kill(worker.pid, signal.SIGTERM)
    for line in reader:
        print '>>>', line.rstrip('\n')
    worker.join()

if __name__ == '__main__':
    main()