jruby-go

README.md

jruby-go

Go's concurrency model on top of JRuby

Channels

Channel.new creates a channel, and you can optionally pass it a capacity: Channel.new(200)

Use << to send on a channel: chan << "stuff"

Use ~ to receive from a channel: puts ~chan

Goroutines

Call go! on a Proc or Method to start a new goroutine: lambda { puts "hello there" }.go!

You can pass arguments to go!: method(:puts).go!("greetings")

You can also call go! top level and pass it a block: go! { puts "make sure not to share mutable state through the closure's context" }

Issues

One thing I didn't solve for: selecting on multiple channels

jruby-go.rb

require 'java'

GOROUTINE_EXECUTOR = java.util.concurrent.Executors.newCachedThreadPool
GOROUTINE_EXECUTOR.set_thread_factory(Class.new do
  include java.util.concurrent.ThreadFactory
  def newThread(r)
    thread = java.util.concurrent.Executors.defaultThreadFactory.newThread(r)
    thread.set_daemon(true)
    thread
  end
end.new)

class Channel
  def initialize(capacity = 100)
    @queue = java.util.concurrent.ArrayBlockingQueue.new(100)
  end

  def <<(message)
    @queue.put(message)
  end

  def ~()
    @queue.take
  end
end

module Goable
  def go!(*args)
    GOROUTINE_EXECUTOR.submit(lambda{self.call(*args)})
  end
end

Method.send(:include, Goable)
Proc.send(:include, Goable)

def go!(*args, &blk)
  blk.go!(*args)
end

sieve.rb

require 'jruby-go'

# jruby-go port of http://golang.org/doc/play/sieve.go

def generate(ch)
  2.upto(1.0/0) do |i|
    ch << i
  end
end

def filter(inn, out, prime)
  loop do
    i = ~inn
    if i % prime != 0
      out << i
    end
  end
end

ch = Channel.new
method(:generate).go!(ch)
# This can also be `go! ch, &method(:generate)`

10.times do
  prime = ~ch
  puts prime
  ch1 = Channel.new
  method(:filter).go!(ch, ch1, prime)
  ch = ch1
end

test.rb

require 'jruby-go'

chan = Channel.new

# << sends on a channel
go! { puts "hello"; chan << "goodbye" }

# ~ receives from a channel
puts ~chan

# You can also call go! on a callable if you want to pass it args
lambda { |a, b| puts a; chan << b }.go!("hola", "adios")
puts ~chan