redis-lock
Requires the redis gem. Including this in your project will give you additional locking abilities on any instance of a redis connection you create.
Installation
gem install redis-lock
Usage
require 'redis'
require 'redis-lock # This will automatically include Lock into the Redis class.
Here's a little example of what you can do with it:
timeout = 10 # measured in seconds
max_attempts = 100 # number of times the action will attempt to lock the key before raising an exception
$redis = Redis.new
$redis.lock('beers_on_the_wall', timeout, max_attempts)
# Now no one can acquire a lock on 'beers_on_the_wall'
$redis.unlock('beers_on_the_wall')
# Other processes can now acquire a lock on 'beers_on_the_wall'
For convenience, there is also a lock_with_update function that accepts a block. It handles the locking and unlocking for you.
$redis.lock_for_update('beers_on_the_wall') do
$redis.multi do
$redis.set('sing', 'take one down, pass it around.')
$redis.decr('beers_on_the_wall')
end
end
Additional Notes
This gem basically implements the algorithm described here: http://redis.io/commands/setnx
Author
Patrick Tulskie; http://patricktulskie.com