README

Redis distributed locks in PHP

Based on Redlock-rb by Salvatore Sanfilippo and Redlock-php by Ronny López. This library implements the Redis-based distributed lock manager algorithm described in this blog post.

Support cluster mode using phpredis PECL extention.

To create a lock manager:

$servers = array(
    array('127.0.0.1', 6379),
    array('127.0.0.1', 6380),
    array('127.0.0.1', 6381),
);

$redLock = new RedLock($servers);

To acquire a lock:

$lock = $redLock->lock('my_resource_name', 1000);

Where the resource name is an unique identifier of what you are trying to lock and 1000 is the number of milliseconds for the validity time.

The returned value is false if the lock was not acquired (you may try again), otherwise an array representing the lock is returned, having three keys:

Array
(
    [validity] => 9897.3020019531
    [resource] => my_resource_name
    [token] => 53771bfa1e775
)

• validity, an integer representing the number of milliseconds the lock will be valid.
• resource, the name of the locked resource as specified by the user.
• token, a random token value which is used to safe reclaim the lock.

To release a lock:

    $redLock->unlock($lock)

It is possible to setup the number of retries (by default 3) and the retry delay (by default 200 milliseconds) used to acquire the lock.

The retry delay is actually chosen at random between $retryDelay / 2 milliseconds and the specified $retryDelay value.

Disclaimer: As stated in the original antirez's version, this code implements an algorithm which is currently a proposal, it was not formally analyzed. Make sure to understand how it works before using it in your production environments.