Producer-consumer problem in Ruby with SizedQueue

producer-consumer.rb

require 'thread'

class ProducerConsumer
  def initialize producers = 5, consumers = 5, queue_size = 5
    @producers, @consumers = producers, consumers
    @queue = SizedQueue.new queue_size
    @mutex = Mutex.new
    @threads = []
  end
  
  def run
    producers
    consumers
  end
  
  def producers
    @producers.times do
      @threads << Thread.new do
        loop do
          @queue << 'a widget'
          say "Produced a widget: #{@queue.size} in queue..."
        end
      end
    end
  end
  
  def consumers
    @consumers.times do
      @threads << Thread.new do
        loop do
          @queue.pop
          say "Consumed a widget: #{@queue.size} in queue..."
        end
      end
    end
  end
  
  def say this
    @mutex.synchronize do
      puts this
    end
  end
  
  def kill
    @threads.each &:kill
  end
end

pc = ProducerConsumer.new
pc.run
sleep 0.5
pc.kill

What kind of problem did you experienced? Is it because access to the queue wasn't properly synchronized between threads?

lol, im just gonna assume that was a joke