How to process SIGTERM signal gracefully?
Let's assume we have such a trivial daemon written in python:
def mainloop(): while True: # 1. do # 2. some # 3. important # 4. job # 5. sleep mainloop()
and we daemonize it using
start-stop-daemon which by default sends
TERM) signal on
Let's suppose the current step performed is
#2. And at this very moment we're sending
What happens is that the execution terminates immediately.
I've found that I can handle the signal event using
signal.signal(signal.SIGTERM, handler) but the thing is that it still interrupts the current execution and passes the control to
So, my question is - is it possible to not interrupt the current execution but handle the
TERM signal in a separated thread (?) so that I was able to set
shutdown_flag = True so that
mainloop() had a chance to stop gracefully?
A class based clean to use solution:
import signal import time class GracefulKiller: kill_now = False def __init__(self): signal.signal(signal.SIGINT, self.exit_gracefully) signal.signal(signal.SIGTERM, self.exit_gracefully) def exit_gracefully(self,signum, frame): self.kill_now = True if __name__ == '__main__': killer = GracefulKiller() while True: time.sleep(1) print("doing something in a loop ...") if killer.kill_now: break print "End of the program. I was killed gracefully :)"
★ Back to homepage or read more recommendations: