Refactor Modbus connection

.rubocop.yml

@@ -25,6 +25,9 @@ Layout/LineLength:
 Layout/MultilineMethodCallIndentation:
   EnforcedStyle: indented
 
+Lint/MissingSuper:
+  Enabled: false
+
 Metrics/AbcSize:
   Exclude:
     - "**/db/migrate/**/*.rb"

Gemfile

@@ -20,11 +20,13 @@ gem "tailwindcss-rails"
 gem "turbo-rails"
 
 ## LIBRARIES
+gem "bindata"
 gem "bootsnap", require: false
+gem "concurrent-ruby"
 gem "foreman"
 gem "http"
+gem "mqtt"
 gem "rails-settings-cached"
-gem "rmodbus"
 gem "rufus-scheduler"
 gem "solid_queue"
 gem "sqids"

Gemfile.lock

@@ -84,6 +84,7 @@ GEM
       rack (>= 0.9.0)
       rouge (>= 1.0.0)
     bigdecimal (3.1.5)
+    bindata (2.4.15)
     bindex (0.8.1)
     bootsnap (1.17.0)
       msgpack (~> 1.2)
@@ -160,6 +161,7 @@ GEM
     matrix (0.4.2)
     mini_mime (1.1.5)
     minitest (5.20.0)
+    mqtt (0.6.0)
     msgpack (1.7.2)
     mutex_m (0.2.0)
     net-imap (0.4.1)
@@ -242,7 +244,6 @@ GEM
     reline (0.4.2)
       io-console (~> 0.5)
     rexml (3.2.6)
-    rmodbus (1.3.3)
     rouge (4.1.3)
     rubocop (1.59.0)
       json (~> 2.3)
@@ -328,18 +329,20 @@ PLATFORMS
 DEPENDENCIES
   amazing_print
   better_errors
+  bindata
   bootsnap
   capybara
+  concurrent-ruby
   debug
   dotenv-rails
   foreman
   http
   importmap-rails
+  mqtt
   propshaft
   puma
   rails
   rails-settings-cached
-  rmodbus
   rubocop
   rubocop-capybara
   rubocop-minitest

app/gateways/application_gateway.rb

@@ -0,0 +1,9 @@
+class ApplicationGateway
+  def close
+    raise NotImplementedError
+  end
+
+  def read(*)
+    raise NotImplementedError
+  end
+end

app/gateways/modbus_mqtt_gateway.rb

@@ -0,0 +1,92 @@
+class ModbusMQTTGateway < ApplicationGateway
+  def initialize
+    @client = initialize_client
+    @transaction = initialize_transaction
+  end
+
+  # rubocop:disable Metrics/MethodLength
+  # rubocop:disable Metrics/AbcSize
+  def read(register)
+    transaction = next_transaction
+
+    promise = Concurrent::Promise.execute do
+      @client.subscribe(mqtt_subscribe_topic)
+
+      request = Modbus::ADU.read_register(
+        transaction, modbus_slave_id, register.address, register.quantity
+      ).to_binary_s
+
+      @client.publish(mqtt_publish_topic, request)
+
+      loop do
+        _topic, message = @client.get
+        adu = Modbus::ADU.parse(message)
+
+        break adu if adu.transaction == transaction
+      end
+    end
+
+    promise.value(30) ? register.from_binary(promise.value.get.data) : nil
+  end
+  # rubocop:enable Metrics/MethodLength
+  # rubocop:enable Metrics/AbcSize
+
+  def close
+    @client&.disconnect
+  end
+
+  private
+
+  def mqtt_host
+    Rails.configuration.x.gateways.modbus_mqtt.host
+  end
+
+  def mqtt_port
+    Rails.configuration.x.gateways.modbus_mqtt.port.try(:to_i)
+  end
+
+  def mqtt_ssl
+    Rails.configuration.x.gateways.modbus_mqtt.ssl.try(:to_boolean)
+  end
+
+  def mqtt_account
+    Rails.configuration.x.gateways.modbus_mqtt.account
+  end
+
+  def mqtt_password
+    Rails.configuration.x.gateways.modbus_mqtt.password
+  end
+
+  def mqtt_subscribe_topic
+    Rails.configuration.x.gateways.modbus_mqtt.subscribe_topic
+  end
+
+  def mqtt_publish_topic
+    Rails.configuration.x.gateways.modbus_mqtt.publish_topic
+  end
+
+  def modbus_slave_id
+    Rails.configuration.x.gateways.modbus_mqtt.slave_id.try(:to_i)
+  end
+
+  def initialize_client
+    MQTT::Client.connect(
+      host: mqtt_host,
+      port: mqtt_port,
+      ssl: mqtt_ssl,
+      username: mqtt_account,
+      password: mqtt_password
+    )
+  end
+
+  def initialize_transaction
+    Random.new.rand(65_535)
+  end
+
+  def next_transaction
+    id = @transaction
+    @transaction += 1
+    @transaction = 0 if @transaction > 65_535 # 2 bytes 0xFFFF
+    id
+  end
+end

app/models/setting.rb

@@ -11,6 +11,5 @@ class Setting < RailsSettings::Base
   field :inverter_brand, type: :string
   field :inverter_model, type: :string
   field :inverter_serial_number, type: :string
-  field :inverter_firmware_version, type: :string
   field :viewed_at, type: :datetime
 end