Pulls energy usage from a Rainforest Automation RAVEn USB stick and publishes into a MQTT server to be consumed by Home Assistant

raven.rb

# License: Public domain
# Depends on https://github.com/nonspecialist/pyraven being installed and accessible at `raven`

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'mqtt'
end

require 'json'
require 'time'

ENV['PYTHONUNBUFFERED'] = 'true'

begin
  IO.popen('raven') do |io|
    puts "Process started, connecting to MQTT server..."
    
    MQTT::Client.connect('mqtt://user:pass@host') do |c|
      puts "Connected to MQTT server."
      
      while line = io.gets do
        begin
          data = JSON.parse(line)
          
          if demand = data['raw_demand']
            puts "#{Time.now.iso8601}\t Demand: #{demand}W"
            c.publish('energy/meter', demand)
          end
          
        rescue StandardError => ex
          $stderr.puts("Error publishing: #{ex}")
        end
      end
      
    end
  end
rescue StandardError => ex
  $stderr.puts("Error: #{ex}")
  $stderr.puts(ex.backtrace.join("\n"))
  $stderr.puts("Restarting...")
  sleep 2
  retry
end