Close server socket on quit/crash

python sockets socketserver
Matt picture Matt · Oct 14, 2011 · Viewed 8.9k times · Source

I'm learning how to use sockets in python, and quite often when my program crashes or I Ctrl+C the server socket somehow stays listening on the port. This obviously stops the program from listening on that port when it starts back up again, so I have to keep changing it.

I'm guessing I need to do socket.close() somewhere, but where?

Answer

Michael Mior picture Michael Mior · Oct 14, 2011

You could try the atexit module.

import atexit

function close_socket:
    s.close()

atexit.register(close_socket)

If the issue is delays in the port becoming available during testing, I would suggest setting SO_REUSEADDR which will allow the port to be bound again immediately instead of waiting for timeouts on the TCP stack. 

s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

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