python限制函数执行时间

from:https://stackoverflow.com/questions/366682/how-to-limit-execution-time-of-a-function-call-in-python
当有些函数执行时间过长，影响整个程序运行时，可以使用此方法进行限制，超时会报错。

from __future__ import with_statement # Required in 2.5

import signal

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)

try:

    with time_limit(10):

        long_function_call()

except TimeoutException, msg:

    print "Timed out!"