Portalocker is a library to provide an easy API to file locking.
Originally created as a Python Recipe by Jonathan Feinberg and Lowell Alleman http://code.activestate.com/recipes/65203-portalocker-cross-platform-posixnt-api-for-flock-s/
To make sure your cache generation scripts don't race, use the Lock class:
>>> import portalocker >>> with portalocker.Lock('somefile', timeout=1) as fh: print >>fh, 'writing some stuff to my cache...'
To lock a file exclusively, use the lock method:
>>> import portalocker >>> file = open('somefile', 'r+') >>> portalocker.lock(file, portalocker.LOCK_EX) >>> file.seek(12) >>> file.write('foo') >>> file.close()
There is no explicit need to unlock the file as it is automatically unlocked after file.close(). If you still feel the need to manually unlock a file than you can do it like this:
Do note that your data might still be in a buffer so it is possible that your data is not available until you flush() or close().
The module is maintaned by Rick van Hattem <Rick.van.Hattem@Fawo.nl>. The project resides at https://github.com/WoLpH/portalocker . Bugs and feature requests can be submitted there. Patches are also very welcome.
See CHANGELOG file
see the LICENSE file