zklock

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Copyright (c) 2011 Joe Rumsey ([email protected]) Released under the LGPL, see COPYING.txt for details

zklock is a python package that provides a simple distributed mutex implementation using zookeeper as the back end.

• HOW TO INSTALL

$ pip install zklock

Or get it from github, see http://github.com/tinyogre/zklock for details

zklock requires zkpython. Additionally, installing zkpython requires the zookeeper C library be installed first. You can download and learn about ZooKeeper here: http://zookeeper.apache.org/. Though ZooKeeper is written in Java, the C library is part of the main distribution.

• WHY DOES THIS EXIST

I'm writing a mobile game that includes an online turn based mode. I started investigating Cassandra for storage of games, but almost immediately found that I needed some kind of row level locking to avoid races with both players updating the same game. Turns in this game are simultaneously executed, and I accept a save from whoever submits it first. Stored chat has a similar issue.

The web interface is built in python with Django. So I needed a lock mechanism for Cassandra in python. I found existing ZooKeeper solutions in Java, but none in Python. So here's this. It's cribbed from several other Java examples out there, but not translated.

• HOW TO USE THIS

See zklocktest.py on github for a simple example.