Battle-hardened distributed locking using redis
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lib return lock id in .lock Jan 4, 2016
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LICENSE Initial commit Mar 6, 2014 return lock id in .lock Jan 4, 2016
package.json 0.2.0 Jan 5, 2016


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Battle-hardened distributed locking using redis.


  • node-redis compatible with v0.10
  • Redis v2.6.12 or above. If you're running a Redis version from v2.6.0 to v2.6.11 inclusive use v0.0.7 of this module.


npm install node-redis-warlock


var Warlock = require('node-redis-warlock');
var redis = require('redis');

// Establish a redis client and pass it to warlock
var redis = redis.createClient();
var warlock = Warlock(redis);

// Set a lock
var key = 'test-lock';
var ttl = 10000; // Lifetime of the lock

warlock.lock(key, ttl, function(err, unlock){
  if (err) {
    // Something went wrong and we weren't able to set a lock

  if (typeof unlock === 'function') {
    // If the lock is set successfully by this process, an unlock function is passed to our callback.
    // Do the work that required lock protection, and then unlock() when finished...
    // do stuff...
  } else {
    // Otherwise, the lock was not established by us so we must decide what to do
    // Perhaps wait a bit & retry...

// set a lock optimistically
var key = 'opt-lock';
var ttl = 10000;
var maxAttempts = 4; // Max number of times to try setting the lock before erroring
var wait = 1000; // Time to wait before another attempt if lock already in place
warlock.optimistic(key, ttl, maxAttempts, wait, function(err, unlock) {});

// unlock using the lock id
var key = 'test-lock-2';
var ttl = 10000;
var lockId;

warlock.lock(key, ttl, function(err, _, id) {
  lockId = id;

// each client who knows the lockId can release the lock
warlock.unlock(key, lockId, function(err, result) {
  if(result == 1) {
    // unlocked successfully