ultrabug/uhashring: Full featured consistent hashing python library compatible with ketama

uhashring implements consistent hashing in pure Python.

Consistent hashing is mostly used on distributed systems/caches/databases as this avoid the total reshuffling of your key-node mappings when adding or removing a node in your ring (called continuum on libketama). More information and details about this can be found in the literature section.

This full featured implementation offers:

a lot of convenient methods to use your consistent hash ring in real world applications. simple integration with other libs such as memcache through monkey patching. a full ketama compatibility if you need to use it (see important mention below). all the missing functions in the libketama C python binding (which is not even available on pypi) for ketama users. possibility to use your own weight and hash functions if you don't care about the ketama compatibility. instance-oriented usage so you can use your consistent hash ring object directly in your code (see advanced usage). native pypy support, since this is a pure python library. tests of implementation, key distribution and ketama compatibility.