Simplest Ruby/Rails Producer-Consumer thread example

mgr.rb

require 'thread'
class Mgr 
  
  # This initiates the queue and the threads 
  def self.run
    @mutex = Mutex.new
    @cv = ConditionVariable.new
    @working = true
    @clue_bank = 0
    10.times{|i|
      puts "#{i} started from (#{Thread.current.inspect}"
      Wrk.new.init(i)
    }
  end
  
  # this methos services the threads to propogate a stop signal
  def self.working?
    @working
  end
  
  # this method is used by the workers to grab a task from the queue
  # if no talk is available the worker is set to sleep untill awakened 
  #   the next time new items are pushed into the queue
  def self.get_a_clue
    @mutex.synchronize {
      if @clue_bank>1
        @clue_bank -=1
        @clue_bank
      else 
        @cv.wait(@mutex)
        false
      end  
    }
  end
  
  
  #this method emulates adding new tasks to the queue
  # note: it is not thread safe because its just a simple example. 
  # if you need this to be thread safe, then wrap it in a mutex.sync
  # just like in the get_a_clue method
  def self.pop(c)
    @clue_bank += c
    @cv.broadcast
  end
  
  #this method is used to announce all the threds to stop and terminate
  def self.stop
    @working = false
    @cv.broadcast
  end
    
end

wrk.rb

require 'open-uri'
class Wrk 
  
  #the main loop around for a particular thread
  def run
    while Mgr.working?
      clue = Mgr.get_a_clue
      puts "runner #{@i} got #{clue} (#{Thread.current.inspect})"
      if clue
        puts "runner #{@i} working..."
        open("http://giladmanor.blogspot.co.il/")
        puts "runner #{@i} done."
      end
    end
  end
  
  # an initialization method for a worker
  # note that the thread is browken off at this point
  def init(i)
    @i = i
    Thread.new {
      self.run
    }
  end
end