Hacky, but effective. I leave this running as the same user running the buildbot. Requires: https://code.google.com/p/psutil/

kill_old_camput.py

"""Kill old camputs. Helper for buildbot."""

import getpass
import logging
import signal
import sys
import time

import psutil

__author__ = "Bill Thiede"
__copyright__ = "Copyright 2013"
__email__ = "python@xinu.tv"

TOO_OLD_SECS = 300
CYCLE_SECS = 60

def main(args):
    logging.basicConfig(format='%(asctime)s %(message)s', level=logging.INFO)
    logging.info('Started')
    while True:
        me = getpass.getuser()
        camputs = [p for p in psutil.process_iter()
                   if p.username==me and p.name=='camput']
        if camputs:
            logging.debug('Found %d camput(s)', len(camputs))

        now = time.time()
        for c in camputs:
            d = now - c.create_time
            if d > TOO_OLD_SECS:
                logging.info('Killing %s', c)
                c.send_signal(signal.SIGQUIT)
            else:
                logging.info('Waiting to kill %s, only %f seconds old', p, d)

        time.sleep(CYCLE_SECS)


if __name__ == '__main__':
    main(sys.argv[1:])