simple, stupid thread pool for running system calls

threaded_systems.rb

MAX_THREADS = 4

def self.run_threaded_systems(tasks)                                                              
  queued_tasks = tasks.each_with_object(Queue.new) do |task, queue|                               
    queue.push(task)                                                                              
  end                                                                                             
  MAX_THREADS.times.inject(Array.new) { |threads|                                                 
    threads << Thread.new(queued_tasks) { |queue|                                                 
      while task = queued_tasks.pop(true) rescue nil                                              
        puts("running command #{task.join(" ")}")                                                 
        system(*task)                                                                             
      end                                                                                         
    }                                                                                             
  }.each { |thread| thread.join }                                                                 
  nil                                                                                             
end