main.rb

require 'thread'

class Test
  def initialize(queue)
    @queue = queue
  end

  def run
    value = nil
    while value = @queue.pop
      Thread.new {
        update(value)
      }
    end
  end

  def update(x)
    sleep 1
    p x
  end
end

queue = Queue.new

Thread.new {
  queue << { 'hello' => 'world' }
  queue << { 'hello2' => 'world2' }
  queue << nil
}

Test.new(queue).run