I have have a main process that forks a number of subprocesses. I want to be able to kill these child processes off when my main process gets the kill signal. Ideally I would want to do something along the lines of:
def handler(signum, frame, pid_list):
log('Killing Process')
for pid in pid_list:
os.kill(pid, signal.SIGTERM)
os.waitpid(pid, 0) # need
sys.exit()
if __name__ == "__main__":
<code that creates child processes, pids>
signal.signal(signal.SIGTERM, handler(pid_list))
But of course, that doesn't work... any suggestions?
As @tony suggested you could set daemon=True flag on a child process created using multiprocessing module. To install it on python2.4, type: pip install multiprocessing.
The child processes won't be terminated if the main process is killed by a signal so you need to provide an appropriate signal handler:
#!/usr/bin/env python
import logging, signal, sys, time
import multiprocessing as mp # `pip install multiprocessing` on Python <2.6
class AddProcessNameFilter(logging.Filter):
"""Add missing on Python 2.4 `record.processName` attribute."""
def filter(self, r):
r.processName = getattr(r, 'processName', mp.current_process().name)
return logging.Filter.filter(self, r)
def print_dot():
while True:
mp.get_logger().info(".")
time.sleep(1)
def main():
logger = mp.log_to_stderr()
logger.setLevel(logging.INFO)
logger.addFilter(AddProcessNameFilter()) # fix logging records
# catch TERM signal to allow finalizers to run and reap daemonic children
signal.signal(signal.SIGTERM, lambda *args: sys.exit(-signal.SIGTERM))
# create daemonic child processes
processes = [mp.Process(target=print_dot) for _ in range(2)]
for p in processes:
p.daemon = True
p.start()
print_dot()
if __name__=="__main__":
mp.freeze_support()
main()
What about use this flag when you create a subprocess?
