ThreadPool

thread_pool.rb

class ThreadPool
  def initialize(input_array:, callback:, threads: 128)
    @callback, @input_array, @threads = callback, input_array, threads
  end

  def run
    results = []
    input_queue, results_queue = Queue.new, Queue.new

    @input_array.each{ |item| input_queue << item }

    workers = (1..@threads).map do
      Thread.new do
        begin
          while item = input_queue.pop(true)
            results_queue << @callback.call(item)
          end
        rescue ThreadError
        end
      end
    end

    # Move data into a regular array
    workers.map(&:join)
    results_queue.length.times{ results << results_queue.pop }

    results
  end
end

2.1.1 :044 > ThreadPool.new(input_array: %w(hello world), callback: ->(item) { item * 2 }, threads: 10).run
 => ["hellohello", "worldworld"]