redis-clustr

redis-clustr

This module is a relatively thin wrapper around the node redis client to enable use of a CRC16-based redis hashring.

It tries to be as unobtrusive as possible - mimicing the behaviour of the core redis client. Multi commands are supported but not as complete transactions, instead the commands are split into a multi for each node in the cluster which is then executed in parallel and the response is recreated in the original order. Multi-key commands (such as del('hello', 'hello2') etc) are also supported and will be grouped into the relevant commands for each node.

Usage

Unless slots are specified, each node will be allocated an equal section of slots (0 - 65535). The order of the clients is essential if no slots are specified.

Basic

var RedisCluster = require('redis-clustr');

var redis = new RedisCluster([
  {
    host: 'localhost',
    port: 6380
  },
  {
    host: 'localhost',
    port: 6381
  },
  {
    host: 'localhost',
    port: 6382
  }
]);

// lets start using the cluster!
redis.set('test', 'value');

var multi = redis.multi();

multi.get('test', function(err, res) {
  // null, 'value'
});

multi.set('test2', 'value2');

multi.del('test', 'test2', function(err) {
  // responses for multi key commands are *not* 100% reliable
});

multi.exec(function(err, res) {
  console.log(err, res);
});

Advanced

Slot ranges can be manually specified, as can redis clients to use (client rather than host and port). Note: if a client is specified, a name must be specified.

var RedisCluster = require('redis-clustr');
var Redis = require('redis');

var redis = new RedisCluster([
  {
    name: 'tiny-client'
    client: Redis.createClient(6380, 'localhost'),
    slots: [ 0, 100 ]
  },
  {
    name: 'little',
    client: Redis.createClient(6381, 'localhost'),
    slots: [ 101, 5000 ]
  },
  {
    name: 'huge-client',
    client: Redis.createClient(6382, 'localhost'),
    slots: [ 5001, 65535 ]
  }
]);

// etc etc