ConsistentHashing 0.2.2

Introduction

Consistent hashing is a special kind of hashing such that when a hash table is resized and consistent hashing is used, only few keys need to be remapped. In contrast, in most traditional hash tables, a change in the number of array slots causes nearly all keys to be remapped.

ConsistentHashing is a very simple implement of concistent hashing.

Usage examples

>>> from consistenthashing import consistenthashing
>>> inst = consistenthashing(nodes=["122.225.109.103","221.236.5.135","58.58.179.52","61.174.51.204","222.186.31.234","182.74.141.242","179.107.90.135"], slotSize=10000, virtualNode=2)
>>> inst.getAllNodes()
['122.225.109.103', '221.236.5.135', '58.58.179.52', '61.174.51.204', '222.186.31.234', '182.74.141.242', '179.107.90.135']
>>> inst.addNode('1.1.1.1')
True
>>> inst.getNode('1')
'61.174.51.204'
>>> inst.getNode('a')
'122.225.109.103'
>>> inst.getNode('hello')
'61.174.51.204'
>>> inst.getNode('consistenthashing')
'1.1.1.1'
>>> inst.getVirtualNodeNumber()
2
>>> inst.getVirtualNodes('221.236.5.135')
['221.236.5.135_virtual1', '221.236.5.135_virtual2']
>>> inst.removeNode('122.225.109.103')
True
>>> inst.addNode('pypi.python.org')
True
>>> inst.getAllNodes()
['221.236.5.135', '58.58.179.52', '61.174.51.204', '222.186.31.234', '182.74.141.242', '179.107.90.135', '1.1.1.1', 'pypi.python.org']

Referencek

• Consistent hashing http://en.wikipedia.org/wiki/Consistent_hashing