Allow only one python script instance

Question

Possible duplicate:
Python: one instance of the program

What is the best way to ensure that only one copy of a python script works? I'm having problems with zombie pythons. I'm tired of creating a write lock with open("lock","w"), but python doesn't notify me if the file already has a write lock, it just seems to be waiting.

Answer 1

Try:

import os
os.open("lock", os.O_CREAT|os.O_EXCL)

Documentation for os.open and its flags .

Answer 2

: Python?. .

( portalocker.LOCK_EX!|portalocker.LOCK_NB . , script .)