I am running a python script in the background using the command python script.py &
. The script might look like this.
import time
def loop():
while True:
time.sleep(1)
if __name__=='__main__':
try:
loop()
except KeyboardInterrupt:
print("Terminated properly")
When it comes to terminating the script, I would like to do some cleanup before it is stopped (such as printing "Terminated properly"). If I run as a current process, this would be handled by the except
statement after a keyboard interrupt.
Using the kill PID
command means the cleanup is never executed. How can I stop a background process and execute some lines of code before it is terminated?
You can use signal module to catch any signals sent to your script via kill. You setup a signal handler to catch the signal in question that would perform the cleanup.
import signal
import time
running = 0
def loop ():
global running
running = 1
while running:
try: time.sleep(0.25)
except KeyboardInterrupt: break
print "Ended nicely!"
def cleanup (signumber, stackframe):
global running
running = 0
signal.signal(signal.SIGABRT, cleanup)
signal.signal(signal.SIGTERM, cleanup)
signal.signal(signal.SIGQUIT, cleanup)
loop()