locky

Fast resource locking system based on redis.

Install

npm install locky

Usage

var Locky = require('locky');

// Create a new locky client.
var locky = new Locky();

// Lock the resource 'article:12' with the locker 20.
locky.lock('article:12', 20).then(...);

// Refresh the lock TTL of the resource 'article:12'.
locky.refresh('article:12').then(...);

// Unlock the resource 'article:12.
locky.unlock('article:12').then(...);

// Get the locker of the resource 'article:12'.
locky.getLocker('article:12').then(...);

new Locky(options)

Create a new locky client with some options.

redis

Type: Object or Function

If you specify an object, the properties will be used to call redis.createClient method.

new Locky({
  redis: {
    port: 6379,
    host: '127.0.0.1',
    connect_timeout: 200
  }
})

If you specify a function, it will be called to create redis clients.

var redis = require('redis');

new Locky({
  redis: createClient
})

function createClient() {
  var client = redis.createClient();
  client.select(1); // Choose a custom database.
  return client;
}

ttl

Type: Number

Define the expiration time of the lock in ms. Defaults to null (no expiration).

new Locky({
  ttl: 2000
})

locky.lock(options, [callback])

Lock a resource for a locker.

If the resource was already locked, you can't lock it but by passing force: true.

locky.lock({
  resource: 'article:23',
  locker: 20,
  force: false
}).then(function (locked) {
  console.log(locked); // true the lock has been taken
});

resource

Type: String | Number

Which resource would you like to lock.

locker

Type: String | Number

Which locker should lock the resource, can by any string.

force

Type: Boolean

Should we take a lock if it's already locked?

locky.refresh(resource, [callback])

Refresh the lock ttl of a resource, if the resource is not locked, do nothing.

// Refresh the resource "article:23".
locky.refresh('article:23').then(...);

locky.unlock(resource, [callback])

Unlock a resource, if the resource is not locked, do nothing.

// Unlock the resource "article:23".
locky.unlock('article:23').then(...);

locky.getLocker(resource, [callback])

Return the locker of a resource, if the resource is not locked, return null.

// Return the locker of the resource "article:23".
locky.getLocker('article:23').then(...);

Events

"lock"

Emitted when a resource is locked.

locky.on('lock', function (resource, locker) { ... });

"unlock"

Emitted when a resource is unlocked.

locky.on('unlock', function (resource) { ... });

"expire"

Emitted when the lock on a resource has expired.

locky.on('expire', function (resource) { ... });

License

MIT