Python subprocess timeout?

Question

Is there any argument or options to setup a timeout for Python\'s subprocess.Popen method?

Something like this:

subprocess.Popen([\'..\'], ..., timeout

Answer 1

For Linux, you can use a signal. This is platform dependent so another solution is required for Windows. It may work with Mac though.

def launch_cmd(cmd, timeout=0):
    '''Launch an external command

    It launchs the program redirecting the program's STDIO
    to a communication pipe, and appends those responses to
    a list.  Waits for the program to exit, then returns the
    ouput lines.

    Args:
        cmd: command Line of the external program to launch
        time: time to wait for the command to complete, 0 for indefinitely
    Returns:
        A list of the response lines from the program    
    '''

    import subprocess
    import signal

    class Alarm(Exception):
        pass

    def alarm_handler(signum, frame):
        raise Alarm

    lines = []

    if not launch_cmd.init:
        launch_cmd.init = True
        signal.signal(signal.SIGALRM, alarm_handler)

    p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
    signal.alarm(timeout)  # timeout sec

    try:
        for line in p.stdout:
            lines.append(line.rstrip())
        p.wait()
        signal.alarm(0)  # disable alarm
    except:
        print "launch_cmd taking too long!"
        p.kill()

    return lines        
launch_cmd.init = False