consistenthash is an implementation of a consistent hash in Go
This technique is explained in these links:
http://en.wikipedia.org/wiki/Consistent_hashing
http://www.tomkleinpeter.com/2008/03/17/programmers-toolbox-part-3-consistent-hashing/
There is also a popular existing quality Go implementation here:
https://github.com/stathat/consistent
This package is not a copy of that and was developed clean-room from the wikipedia article. Check out that link also if you are evaluating software to provide this functionality.