Example of a with-statement that allows to define a timeout for code execution.

timeout.py

#!/usr/bin/env python

"""timeout.py: Example of a with-statement that allows to define a timeout for code execution."""

__author__      = "Jochen Breuer"
__license__ = "Public Domain"
__email__ = "[email protected]"

import signal
from time import sleep
from contextlib import contextmanager

class TimeoutException(Exception): pass

@contextmanager
def time_limit(seconds):
    def signal_handler(signum, frame):
        raise TimeoutException, "Timed out!"
    signal.signal(signal.SIGALRM, signal_handler)
    signal.alarm(seconds)
    try:
        yield
    finally:
        signal.alarm(0)


def takes_too_long():
    """\
    This function will be interrupted, because it takes too long to finish.
    """
    print("starting to sleep...")
    sleep(5)
    print("... and done!")

def fast_enough():
    """\
    This function finishes in time.
    """
    print "foo"


try:
    with time_limit(2):
        fast_enough()
        takes_too_long()
except TimeoutException, msg:
    print "message: %s" % (msg, )