Based on tendo.singleton
This module provides a Singlet() class which atomically creates a lock file containing PID of the running process to prevent parallel execution of the same program.
In case there is any other instance running already a SingletException will be thrown.
The class will throw IOError and OSError in case there are hardware or OS level corruption.
>>> from singletony import Singlet
... me = Singlet(filename="test.lock", path="/tmp")
This is helpful for both daemons and simple crontab scripts. Works on *NIX and Windows OS's.
By default this creates a lock file with a filename based on the program name. In case you want to remove the file or finish the lock beforehand just delete the instance.