Python Daemon Thread Exits But Process Still Run In The Background

I am using python 2.7 and Python thread doesn't kill its process after the main program exits. (checking this with the ps -ax command on ubuntu machine) I have the below thread cl

Solution 1:

It is likely because you are using os.system in your thread. The spawned process from os.system will stay alive even after the thread is killed. Actually, it will stay alive forever unless you explicitly terminate it in your code or by hand (which it sounds like you are doing ultimately) or the spawned process exits on its own. You can do this instead:

import atexit
import subprocess

deviceIp = '100.21.143.168'
fileTag = 'somefile'# this is spawned in the background, so no threading code is needed
cmdTorun = "adb logcat > " + deviceIp +'_'+fileTag+'.log'
proc = subprocess.Popen(cmdTorun, shell=True)

# or register proc.kill if you feel like living on the edge
atexit.register(proc.terminate)

# Here is where all the other awesome code goes

Since all you are doing is spawning a process, creating a thread to do it is overkill and only complicates your program logic. Just spawn the process in the background as shown above and then let atexit terminate it when your program exits. And/or call proc.terminate explicitly; it should be fine to call repeatedly (much like close on a file object) so having atexit call it again later shouldn't hurt anything.