Add MQTT client wrapper; wire startup publish; support env-config

cmd/server/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"fmt"
 	"log"
 	"net/http"
 	"os"
@@ -11,12 +12,46 @@ import (
 
 	"github.com/gin-gonic/gin"
 
+	"git.piskot.si/SeminarM2/lambdaiot-core/internal/config"
+	mqttclient "git.piskot.si/SeminarM2/lambdaiot-core/internal/mqtt"
 	"git.piskot.si/SeminarM2/lambdaiot-core/internal/handler"
 	"git.piskot.si/SeminarM2/lambdaiot-core/internal/middleware"
 )
-
 func main() {
-	addr := ":8080"
+	// load configuration (look for ./config.toml by default)
+	cfg, err := config.Load("")
+	if err != nil {
+		log.Fatalf("failed to load config: %v", err)
+	}
+
+	// determine address
+	addr := cfg.Server.Address
+	if addr == "" {
+		addr = ":8080"
+	}
+	if cfg.Server.Port != 0 {
+		addr = fmt.Sprintf(":%d", cfg.Server.Port)
+	}
+
+	// connect to MQTT broker (best-effort)
+	var mq *mqttclient.Client
+	if cfg.MQTT.Broker != "" {
+		mqc, err := mqttclient.Connect(cfg.MQTT)
+		if err != nil {
+			log.Printf("warning: mqtt connect failed: %v", err)
+		} else {
+			mq = mqc
+			// publish a startup message (non-blocking)
+			go func() {
+				msg := fmt.Sprintf("lambdaiot-core started on %s", addr)
+				if err := mq.Publish(cfg.MQTT.Topic, []byte(msg)); err != nil {
+					log.Printf("mqtt publish failed: %v", err)
+				}
+			}()
+		}
+	}
+
+    
 
 	// Gin setup
 	r := gin.New()
@@ -30,7 +65,7 @@ func main() {
 
 	// Protected routes
 	auth := r.Group("/")
-	auth.Use(middleware.AuthMiddleware(getJWTSecret()))
+	auth.Use(middleware.AuthMiddleware(cfg.Server.JWTSecret))
 	auth.GET("/protected", handler.Protected)
 
 	srv := &http.Server{
@@ -53,6 +88,9 @@ func main() {
 	if err := srv.Shutdown(ctx); err != nil {
 		log.Fatalf("server forced to shutdown: %v", err)
 	}
+	if mq != nil {
+		mq.Close()
+	}
 	log.Println("server exiting")
 }