PHP Ketama

This is a pure-PHP implementation of libketama, a consistent hashing library.

Compatibility with libketama

PHP Ketama uses the same algorithm as libketama, and will always return the same results as libketama.

The API is not compatible.

Speed

Loading a cached continuum file is faster in PHP Ketama. Hashing is slower. As per the included benchmark, this makes PHP Ketama faster than libketama when doing up to 200 hashes per instance.

Usage

<?php

use Ketama\Ketama;
use Symfony\Component\Cache\Adapter\ApcuAdapter;
use Symfony\Component\Cache\Psr16Cache;

// Cache used to store the parsed continuum file
$cache = new Psr16Cache(new ApcuAdapter('mynamespace')

$ketama = new Ketama($cache);
$continuum = $ketama->createContinuum('/some/file');

// Lookup server
$ip = $continuum->getServer("some key");

Continuum file:

# server    weight
server1 1
server2 3
server3 1
server4 2