sigalarm.py

from time import sleep
import signal
import random

TIMEOUT = 3

def long_running_op():
    print("Starting long-running op..")
    for i in xrange(5):
        duration = random.uniform(0.5, 3.1)
        print("Running operation for %f seconds" % duration)
        sleep(duration)
        print("Step completed, reseting SIGALARM timer")
        signal.alarm(TIMEOUT)

    print("Completed, clearing SIGALARM timer")
    signal.alarm(0)

def main():
    def signal_handler(sig_num, stack_frame):
        print("Signal handler called")
        raise ValueError("abort")

    signal.signal(signal.SIGALRM, signal_handler)

    signal.alarm(TIMEOUT)
    long_running_op()

if __name__ == "__main__":
    main()