mqtt_publish_sample.rb

#
# mqtt publish sample
#
#   $ gem install mqtt
#   $ gem install pit
#
require 'rubygems'
require 'mqtt'
require 'json'
require 'pit'

def mqtt_pub(config_name, topic, key, value)
  config = Pit.get(config_name,
    :require => {
      "remote_host" => "mqtt.example.com",
      "remote_port" => 1883,
      "username" => "username",
      "password" => "password",
    })
  config["remote_port"] = config["remote_port"].to_i

  begin
    MQTT::Client.connect(config) do |c|
      h = {}
      h[key] = value
      json_str = JSON.generate(h)
      c.publish(topic, json_str)
    end
  rescue Exception => e
    puts e
  end
end
mqtt_pub("setting_name", "topic", "key", 12345)