mqtt.lua

-- initiate the mqtt client and set keepalive timer to 120sec
mqtt2 = mqtt.Client("huzzah", 120, "user", "pass")

mqtt2:on("connect", function(con) print ("connected") end)
mqtt2:on("offline", function(con) print ("offline") end)

-- on receive message
mqtt2:on("message", function(conn, topic, data)
  print(topic .. ":" )
  if data ~= nil then
    print(data)
  end
end)

mqtt2:connect("m13.cloudmqtt.com", 12759, 0, function(conn) 
  print("connected")
  -- subscribe topic with qos = 0
  mqtt2:subscribe("my_topic",0, function(conn) 
    -- publish a message with data = my_message, QoS = 0, retain = 0
    mqtt2:publish("my_topic","my_message",0,0, function(conn) 
      print("sent")
    end)
  end)
end,
function(conn, reason)
    print("failed: ", reason)
end)