An extended version of portalocker to lock files in Python using the with statement
Latest commit 3f8fde0 Jan 14, 2017 @WoLpH Merge tag 'v1.0.1' into develop
changed default for fail_when_locked to be more logical


portalocker - Cross-platform locking library

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Portalocker is a library to provide an easy API to file locking.

An important detail to note is that on Linux and Unix systems the locks are advisory by default. By specifying the -o mand option to the mount command it is possible to enable mandatory file locking on Linux. This is generally not recommended however. For more information about the subject:

The module is currently maintained by Rick van Hattem <>. The project resides at . Bugs and feature requests can be submitted there. Patches are also very welcome.



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 customize the opening and locking a manual approach is also possible:

>>> import portalocker
>>> file = open('somefile', 'r+')
>>> portalocker.lock(file, portalocker.LOCK_EX)
>>> 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:

>>> portalocker.unlock(file)

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().

More examples can be found in the tests.


See the changelog page.


See the LICENSE file.