Awesome

Note:

This project is no longer maintained. You might want to take a look at the fork leandromoreira/redlock-rb.

Redlock-rb - Redis distributed locks in Ruby

This Ruby lib implements the Redis-based distributed lock manager algorithm described in this blog post.

To create a lock manager:

dlm = Redlock.new("redis://127.0.0.1:6379","redis://127.0.0.1:6380","redis://127.0.0.1:6381")

To acquire a lock:

my_lock = dlm.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 hash representing the lock is returned, having three fields:

• :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.
• :val, a random value which is used to safe reclaim the lock.

To release a lock:

dlm.unlock(my_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 is actually choosen at random between 0 milliseconds and the specified value. The set_retry method can be used in order to configure the retry count and delay range:

dlm.set_retry(3,200)

Disclaimer: 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.