Receive desire from AWS IoT and send command to real-device (Commander)

awsiot_commander.rb

# Receive desire from AWS IoT and send command to real-device (Commander)
#
# POINT:
# * Listen on /update/delta
# <when Received a delta...>
# 1. Parse the delta
# 2. Execute command according to content
# 3. Erase on 'desired'
#    => Should be removed "desired" ASAP after parsing delta
#       Remains "desired" is cause of trouble (e.g. Out of sync)
#       But, erasing is necessary to consider. In case of failure the delta may be needed

require "mqtt"   # NOTE: https://github.com/njh/ruby-mqtt
require "./patlite"
require "logger"
require "json"

# TODO: parameter-fy
thing_name = "patlite0"
Patlite.host = "192.168.254.209"
logger = Logger.new(STDERR)
logger.level = Logger::DEBUG
CONNECT_PARAMS = {
  host: "data.iot.ap-northeast-1.amazonaws.com", port: 8883, ssl: true,
  cert_file: "awsiot_thing-certificate.pem.crt", key_file:  "awsiot_thing-private.pem.key",
  ca_file:   "VeriSign-Class_3-Public-Primary-Certification-Authority-G5.pem"
}

MQTT::Client.connect(CONNECT_PARAMS) do |c|
  c.get("$aws/things/#{thing_name}/shadow/update/delta") do |_, message| # Flow: Listen on /update/delta
    JSON.parse(message).tap{|d|logger.debug(d)}["state"].each do |target, state| # Flow: Parsing delta
      begin
        Patlite.new(target.downcase.to_sym).send(state.downcase.to_sym) # Flow: Execute command to real-device # NOTE: e.g.) Patlite.new(:red).send(:on)
      rescue NameError # NOTE: Ignore if unknown 'target and/or 'state'
        logger.info($!.to_s)
        logger.info("payload: #{m}")
      end
    end

    MQTT::Client.connect(CONNECT_PARAMS) do |k| # Flow: Erase on 'desired'
      k.publish("$aws/things/#{thing_name}/shadow/update", {state:{desired:nil}}.to_json)
    end
  end
end