Contents

# Suo [![Build Status](https://travis-ci.org/nickelser/suo.svg?branch=master)](https://travis-ci.org/nickelser/suo) [![Gem Version](https://badge.fury.io/rb/suo.svg)](http://badge.fury.io/rb/suo)

:lock: Distributed semaphores using Memcached or Redis in Ruby.

Suo provides a very performant distributed lock solution using Compare-And-Set (`CAS`) commands in Memcached, and `WATCH/MULTI` in Redis.

## Installation

Add this line to your application’s Gemfile:

```ruby
gem 'suo'
```

## Usage

### Basic

```ruby
# Memcached
suo = Suo::Client::Memcached.new(connection: "127.0.0.1:11211")

# Redis
suo = Suo::Client::Redis.new(connection: {host: "10.0.1.1"})

# Pre-existing client
suo = Suo::Client::Memcached.new(client: some_dalli_client)

suo.lock("some_key") do
  # critical code here
  @puppies.pet!
end

Thread.new { suo.lock("other_key", 2) { puts "One"; sleep 2 } }
Thread.new { suo.lock("other_key", 2) { puts "Two"; sleep 2 } }
Thread.new { suo.lock("other_key", 2) { puts "Three" } }

# will print "One" "Two", but not "Three", as there are only 2 resources

# custom acquisition timeouts (time to acquire)
suo = Suo::Client::Memcached.new(client: some_dalli_client, acquisition_timeout: 1) # in seconds

# manually locking/unlocking
suo.lock("a_key")
foo.baz!
suo.unlock("a_key")

# custom stale lock cleanup (cleaning of dead clients)
suo = Suo::Client::Redis.new(client: some_redis_client, stale_lock_expiration: 60*5)
```

## TODO
 - better stale key handling (refresh blocks)
 - more race condition tests

## History

View the [changelog](https://github.com/nickelser/suo/blob/master/CHANGELOG.md)

## Contributing

Everyone is encouraged to help improve this project. Here are a few ways you can help:

- [Report bugs](https://github.com/nickelser/suo/issues)
- Fix bugs and [submit pull requests](https://github.com/nickelser/suo/pulls)
- Write, clarify, or fix documentation
- Suggest or add new features

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
suo-0.2.1	README.md
suo-0.2.0	README.md