Using EventMachine to execute commands in several host at once

remote_commands.rb

require 'eventmachine'
require 'colorize'

class RemoteCommands < EM::Connection
  attr_reader :queue

  def initialize(q)
    @queue = q

    cb = Proc.new do |msg|
      send_data("#{msg}\n")
      q.pop &cb
    end

    q.pop &cb
  end

  def post_init

  end

  def receive_data data
    puts "#{hostname.yellow} says:"
    puts "#{@hostname} says #{data}"
  end

  def unbind
    puts "Process died with exit status: #{get_status.exitstatus}"
    EM.stop
  end

  private

  def hostname
    @hostname ||= `hostname`.gsub!(/\n/,"")
  end
end

class KeyboardHandler < EM::Connection
  include EM::Protocols::LineText2

  attr_reader :queue

  def initialize(q)
    @queue = q
    EM.add_timer(0.01) { print "> " }
  end

  def receive_line(data)
    @queue.push(data)
    EM.add_timer(0.01) { print "> " }
  end
end

EM.run do
  q = EM::Queue.new

  EM.popen "ssh user1@host1", RemoteCommands, q
  EM.popen "ssh user2@host2", RemoteCommands, q
  EM.open_keyboard KeyboardHandler, q
end