Modern concurrency tools for Ruby. Inspired by Erlang, Clojure, Scala, Haskell, F#, C#, Java, and classic concurrency patterns.

The design goals of this gem are:

• Stay true to the spirit of the languages providing inspiration
• But implement in a way that makes sense for Ruby
• Keep the semantics as idiomatic Ruby as possible
• Support features that make sense in Ruby
• Exclude features that don't make sense in Ruby
• Be small, lean, and loosely coupled

• Clojure-inspired Agent
• Clojure-inspired Future
• Scala-inspired Actor
• JavaScript-inspired Promise
• Java-inspired Thread Pools
• Old school events from back in my Visual C++ days
• Repeated task execution with Java-inspired TimerTask service
• Scheduled task execution with Java-inspired ScheduledTask service
• Erlang-inspired Supervisor for managing long-running threads
• Actor variant Channel loosely based on the MailboxProcessor agent in F#

This gem adheres to the rules of semantic versioning.

MRI 1.9.2, 1.9.3, 2.0, 2.1, JRuby (1.9 mode), and Rubinius 2.x. This library is pure Ruby and has no gem dependencies. It should be fully compatible with any Ruby interpreter that is 1.9.x compliant.

Many more code examples can be found in the documentation for each class (linked above). This one simple example shows some of the power of this gem.

require 'concurrent'
require 'faker'

class EchoActor < Concurrent::Actor
  def act(*message)
    puts "#{message} handled by #{self}"
  end
end

mailbox, pool = EchoActor.pool(5)

timer_proc = proc do
  mailbox.post(Faker::Company.bs)
end

t1 = Concurrent::TimerTask.new(execution_interval: rand(5)+1, &timer_proc)
t2 = Concurrent::TimerTask.new(execution_interval: rand(5)+1, &timer_proc)

overlord = Concurrent::Supervisor.new

overlord.add_worker(t1)
overlord.add_worker(t2)
pool.each{|actor| overlord.add_worker(actor)}

overlord.run!

#=> ["mesh proactive platforms"] handled by #<EchoActor:0x007fa5ac18bdf8>
#=> ["maximize sticky portals"] handled by #<EchoActor:0x007fa5ac18bdd0>
#=> ["morph bleeding-edge markets"] handled by #<EchoActor:0x007fa5ac18bd80>
#=> ["engage clicks-and-mortar interfaces"] handled by #<EchoActor:0x007fa5ac18bd58>
#=> ["monetize transparent infrastructures"] handled by #<EchoActor:0x007fa5ac18bd30>
#=> ["morph sexy e-tailers"] handled by #<EchoActor:0x007fa5ac18bdf8>
#=> ["exploit dot-com models"] handled by #<EchoActor:0x007fa5ac18bdd0>
#=> ["incentivize virtual deliverables"] handled by #<EchoActor:0x007fa5ac18bd80>
#=> ["enhance B2B models"] handled by #<EchoActor:0x007fa5ac18bd58>
#=> ["envisioneer real-time architectures"] handled by #<EchoActor:0x007fa5ac18bd30>

overlord.stop

Remember, there is no silver bullet in concurrent programming. Concurrency is hard. These tools will help ease the burden, but at the end of the day it is essential that you know what you are doing.

• Decouple business logic from concurrency logic
• Test business logic separate from concurrency logic
• Keep the intersection of business logic and concurrency and small as possible
• Don't share mutable data unless absolutely necessary
• Protect shared data as much as possible (prefer immutability)
• Don't mix Ruby's concurrency primitives with asynchronous concurrency libraries

• Michele Della Torre
• Giuseppe Capizzi
• Brian Shirai
• Chip Miller
• Jamie Hodge
• Zander Hill

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

I've given several conference presentations on concurrent programming with this gem. Check them out:

• "Advanced Concurrent Programming in Ruby" at RubyConf 2013 used this version of the presentation and is available for viewing on Confreaks
• "Advanced Multithreading in Ruby" at Cascadia Ruby 2013 used this version of the presentation and is available for viewing on Confreaks
• Cleveland Ruby Brigade meetup in December of 2013 used this version of the presentation
• I'll be giving "Advanced Concurrent Programming in Ruby" at CodeMash 2014

Concurrent Ruby is Copyright © 2013 Jerry D'Antonio. It is free software released under the MIT License.