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Consistent hashing "hashring" implementation in golang (using the same algorithm as libketama)
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uepoch and serialx Allow passing a hash.Hash at creation time
This will let users use more efficient hash functions if they need to

Also added some benchs
Latest commit 7706f26 Apr 25, 2019
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LICENSE Add MIT license Feb 2, 2016
README.md fix README.md example incorrect Jun 5, 2017
hashring.go Allow passing a hash.Hash at creation time May 15, 2019
hashring_test.go Allow passing a hash.Hash at creation time May 15, 2019

README.md

hashring

Implements consistent hashing that can be used when the number of server nodes can increase or decrease (like in memcached). The hashing ring is built using the same algorithm as libketama.

This is a port of Python hash_ring library https://pypi.python.org/pypi/hash_ring/ in Go with the extra methods to add and remove nodes.

Using

Importing ::

import "github.com/serialx/hashring"

Basic example usage ::

memcacheServers := []string{"192.168.0.246:11212",
                            "192.168.0.247:11212",
                            "192.168.0.249:11212"}

ring := hashring.New(memcacheServers)
server, _ := ring.GetNode("my_key")

To fulfill replication requirements, you can also get a list of servers that should store your key.

serversInRing := []string{"192.168.0.246:11212",
                          "192.168.0.247:11212",
                          "192.168.0.248:11212",
                          "192.168.0.249:11212",
                          "192.168.0.250:11212",
                          "192.168.0.251:11212",
                          "192.168.0.252:11212"}

replicaCount := 3
ring := hashring.New(serversInRing)
server, _ := ring.GetNodes("my_key", replicaCount)

Using weights example ::

weights := make(map[string]int)
weights["192.168.0.246:11212"] = 1
weights["192.168.0.247:11212"] = 2
weights["192.168.0.249:11212"] = 1

ring := hashring.NewWithWeights(weights)
server, _ := ring.GetNode("my_key")

Adding and removing nodes example ::

memcacheServers := []string{"192.168.0.246:11212",
                            "192.168.0.247:11212",
                            "192.168.0.249:11212"}

ring := hashring.New(memcacheServers)
ring = ring.RemoveNode("192.168.0.246:11212")
ring = ring.AddNode("192.168.0.250:11212")
server, _ := ring.GetNode("my_key")
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