implemented log levels and structured log with slog

Backend/main.go

@@ -5,8 +5,7 @@ import (
 	"arbeitszeitmessung/helper"
 	"arbeitszeitmessung/models"
 	"context"
-	"fmt"
-	"log"
+	"log/slog"
 	"net/http"
 	"os"
 	"time"
@@ -17,23 +16,25 @@ import (
 
 func main() {
 	var err error
+	var logLevel slog.LevelVar
+	logLevel.Set(slog.LevelWarn)
+
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: &logLevel}))
+	slog.SetDefault(logger)
 
 	err = godotenv.Load(".env")
 	if err != nil {
-		log.Println("No .env file found in directory!")
+		slog.Info("No .env file found in directory!")
 	}
 	if helper.GetEnv("GO_ENV", "production") == "debug" {
-		log.Println("Debug mode enabled")
-		log.Println("Environment Variables")
+		logLevel.Set(slog.LevelDebug)
 		envs := os.Environ()
-		for _, e := range envs {
-			fmt.Println(e)
-		}
+		slog.Debug("Debug mode enabled", "Environment Variables", envs)
 	}
 
 	models.DB, err = OpenDatabase()
 	if err != nil {
-		log.Fatal(err)
+		slog.Error("Error while opening the database", "Error", err)
 	}
 
 	fs := http.FileServer(http.Dir("./static"))
@@ -58,14 +59,15 @@ func main() {
 	serverSessionMiddleware := endpoints.Session.LoadAndSave(server)
 
 	// starting the http server
-	fmt.Printf("Server is running at http://localhost:%s\n", helper.GetEnv("EXPOSED_PORT", "8080"))
-	log.Fatal(http.ListenAndServe(":8080", serverSessionMiddleware))
+	slog.Info("Server is running at http://localhost:8080")
+	slog.Error("Error starting Server", "Error", http.ListenAndServe(":8080", serverSessionMiddleware))
 }
 
 func ParamsMiddleware(next http.HandlerFunc) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		queryParams := r.URL.Query()
 		ctx := context.WithValue(r.Context(), "urlParams", queryParams)
+		slog.Debug("ParamsMiddleware added urlParams", slog.Any("urlParams", queryParams))
 		next.ServeHTTP(w, r.WithContext(ctx))
 	})
 }