Simple pipeline using Threads and Queues

pipe.rb

require "thread"

stage_one    = Queue.new
stage_two    = Queue.new
stage_three  = Queue.new

stage_one_worker = Thread.new do
  100.times do |n|
    stage_one << n
    
    sleep 1
  end
end

stage_two_worker = Thread.new do
  while true
    n = stage_one.pop
    
    stage_two << n ** 2
  end
end

stage_three_worker = Thread.new do
  while true
    n = stage_two.pop
    
    stage_three << n + 10
  end
end

final_stage = Thread.new do
  while data = stage_three.pop
    puts "final stage data received: #{data}"
  end
end

[stage_one_worker, stage_two_worker, stage_three_worker, final_stage].each(&:join)