Реализация device-control-service: gRPC + MQTT + Device Shadow в Redis

Добавлен gRPC-контракт proto/device_control (TurnOn/TurnOff/SetLevel),
общий Go-модуль proto/ для переиспользования сгенерированного кода.
device-control-service принимает команды по gRPC, обновляет desired_state
в Redis и публикует их в MQTT; слушает devices/+/telemetry и devices/+/ack
для отметки живости устройства и обновления reported_state; горутина
health-check переводит устройство в offline по таймауту и публикует
событие в RabbitMQ (device.status_changed) для будущего notification-service.

Проверено сквозным тестом через docker compose: grpcurl TurnOn/SetLevel
меняет desired_state и уходит в MQTT, mosquitto_pub с ack обновляет
reported_state и статус, health-check автоматически переводит устройство
в offline по истечении таймаута.

services/device-control-service/internal/server/server.go

@@ -0,0 +1,86 @@
+// Package server implements the DeviceControl gRPC service: it patches the
+// device's desired state in Redis and dispatches the command over MQTT.
+// It deliberately does not wait for the device to execute the command —
+// see the Device Shadow note in the service README.
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+
+	devicecontrol "git.cactoz.su/cacto/home_automatization/proto/device_control"
+)
+
+// ShadowPatcher is the subset of shadow.Store the server needs.
+type ShadowPatcher interface {
+	PatchDesiredState(ctx context.Context, deviceID string, patch map[string]any) error
+}
+
+// CommandPublisher is the subset of mqttclient.Client the server needs.
+type CommandPublisher interface {
+	Publish(topic string, qos byte, retained bool, payload []byte) error
+}
+
+type Server struct {
+	devicecontrol.UnimplementedDeviceControlServer
+
+	shadow ShadowPatcher
+	mqtt   CommandPublisher
+	logger *slog.Logger
+}
+
+func New(shadow ShadowPatcher, mqtt CommandPublisher, logger *slog.Logger) *Server {
+	return &Server{shadow: shadow, mqtt: mqtt, logger: logger}
+}
+
+func (s *Server) TurnOn(ctx context.Context, req *devicecontrol.TurnOnRequest) (*devicecontrol.CommandResult, error) {
+	return s.dispatch(ctx, req.GetDeviceId(),
+		map[string]any{"power": "on"},
+		map[string]any{"action": "turn_on"},
+	)
+}
+
+func (s *Server) TurnOff(ctx context.Context, req *devicecontrol.TurnOffRequest) (*devicecontrol.CommandResult, error) {
+	return s.dispatch(ctx, req.GetDeviceId(),
+		map[string]any{"power": "off"},
+		map[string]any{"action": "turn_off"},
+	)
+}
+
+func (s *Server) SetLevel(ctx context.Context, req *devicecontrol.SetLevelRequest) (*devicecontrol.CommandResult, error) {
+	return s.dispatch(ctx, req.GetDeviceId(),
+		map[string]any{"level": req.GetLevel()},
+		map[string]any{"action": "set_level", "level": req.GetLevel()},
+	)
+}
+
+// dispatch is shared by all three RPCs: patch desired state first (so the UI
+// gets an instant, optimistic view even if the device is offline), then hand
+// the command to MQTT. Business failures come back as CommandResult.Error,
+// not a gRPC error — the wire contract is success/error in one message.
+func (s *Server) dispatch(ctx context.Context, deviceID string, desiredPatch, commandPayload map[string]any) (*devicecontrol.CommandResult, error) {
+	if deviceID == "" {
+		return &devicecontrol.CommandResult{Success: false, Error: "device_id is required"}, nil
+	}
+
+	if err := s.shadow.PatchDesiredState(ctx, deviceID, desiredPatch); err != nil {
+		s.logger.Error("patch desired state failed", "device_id", deviceID, "error", err)
+		return &devicecontrol.CommandResult{Success: false, Error: "failed to update desired state"}, nil
+	}
+
+	body, err := json.Marshal(commandPayload)
+	if err != nil {
+		s.logger.Error("encode command failed", "device_id", deviceID, "error", err)
+		return &devicecontrol.CommandResult{Success: false, Error: "failed to encode command"}, nil
+	}
+
+	topic := fmt.Sprintf("devices/%s/commands", deviceID)
+	if err := s.mqtt.Publish(topic, 1, false, body); err != nil {
+		s.logger.Error("publish command failed", "device_id", deviceID, "topic", topic, "error", err)
+		return &devicecontrol.CommandResult{Success: false, Error: "failed to dispatch command"}, nil
+	}
+
+	return &devicecontrol.CommandResult{Success: true}, nil
+}