Question

I’d like to control a bash program from within Python. I’d like to run an external command every x seconds for y seconds, and then kill it after y seconds. I’m having a bit of trouble with threads and sleep and wait and etc. and am wondering if someone can post a simple example.

For example, from the CLI the usage might be

./foo.py --runfor=10 --runevery=60

meaning foo.py would run something for 10 seconds every 60 seconds (not 60 seconds between). If it is off by a second or fractions of a second that is OK. I can do this by spawning a process that is blocking, and then doing some math to set the timer, but I think there might be a more elegant way with threads.

Answer 1

does this help?

import threading
import subprocess
import time

class IntervalRunner(threading.Thread):
    def __init__(self, seconds):
        self.seconds = seconds
        threading.Thread.__init__(self)

    def run(self):
        while True:
            p = subprocess.Popen('ls -la'.split(), shell=False,
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE)

            stdout, stderr = p.communicate()
            print stdout
            time.sleep(self.seconds)

runner = IntervalRunner(10)
runner.start()
runner.join()