mirror of
https://github.com/dkam/suo.git
synced 2025-01-29 07:42:43 +00:00
87 lines
2.8 KiB
Markdown
87 lines
2.8 KiB
Markdown
# Suo [](https://travis-ci.org/nickelser/suo) [](https://codeclimate.com/github/nickelser/suo) [](https://codeclimate.com/github/nickelser/suo) [](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
|
||
# the return value from lock without a block is a unique token valid only for the current lock
|
||
# which must be unlocked manually
|
||
lock = suo.lock("a_key")
|
||
foo.baz!
|
||
suo.unlock("a_key", lock)
|
||
|
||
# custom stale lock expiration (cleaning of dead locks)
|
||
suo = Suo::Client::Redis.new(client: some_redis_client, stale_lock_expiration: 60*5)
|
||
```
|
||
|
||
### Stale locks
|
||
|
||
"Stale locks" - those acquired more than `stale_lock_expiration` (defaulting to 3600 or one hour) ago - are automatically cleared during any operation on the key (`lock`, `unlock`, `refresh`). The `locked?` method will not return true if only stale locks exist, but will not modify the key itself.
|
||
|
||
To re-acquire a lock in the middle of a block, you can use the refresh method on client.
|
||
|
||
```ruby
|
||
suo = Suo::Client::Redis.new
|
||
|
||
# lock is the same token as seen in the manual example, above
|
||
suo.lock("foo") do |lock|
|
||
5.times do
|
||
baz.bar!
|
||
suo.refresh("foo", lock)
|
||
end
|
||
end
|
||
```
|
||
|
||
## TODO
|
||
- 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
|