Added OpenTelemetry and use structured logging

cmd/api-server/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"context"
 	"errors"
-	"log"
+	"log/slog"
 	"net/http"
 	"os"
 	"os/signal"
@@ -11,9 +11,44 @@ import (
 	"time"
 
 	"github.com/robindittmar/dttmr-api/internal/api/router"
+	"github.com/robindittmar/dttmr-api/internal/telemetry"
 )
 
 func main() {
+	serviceName := "dttmr-api"
+	serviceVersion := "0.1.0"
+
+	if err := run(serviceName, serviceVersion); err != nil {
+		slog.Error("Service crashed", slog.Any("error", err))
+		os.Exit(1)
+	}
+}
+
+func run(serviceName string, serviceVersion string) error {
+	baseHandler := slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
+		Level: slog.LevelInfo,
+	})
+	traceHandler := &telemetry.TraceHandler{Handler: baseHandler}
+
+	logger := slog.New(traceHandler)
+	slog.SetDefault(logger)
+
+	slog.Info("Starting service", slog.String("service", serviceName), slog.String("version", serviceVersion))
+
+	shutdownTelemetry, err := telemetry.Init(context.Background(), serviceName, serviceVersion)
+	if err != nil {
+		slog.Error("Failed to initialize telemetry", err)
+		return err
+	}
+	defer func() {
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+
+		if err := shutdownTelemetry(shutdownCtx); err != nil {
+			slog.Error("Failed to shutdown telemetry", err)
+		}
+	}()
+
 	cfg := router.Config{}
 	mux := router.NewMux(cfg)
 
@@ -26,22 +61,26 @@ func main() {
 	}
 
 	go func() {
-		log.Printf("Listening on %s\n", srv.Addr)
+		slog.Info("Starting http server", "addr", srv.Addr)
 		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
-			log.Fatalf("Failed to start server: %v", err)
+			slog.Error("Failed to start http server", err)
+			os.Exit(1)
 		}
 	}()
 
 	quit := make(chan os.Signal, 1)
 	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
-	<-quit
-	log.Println("Shutting down server...")
+	sig := <-quit
+	slog.Info("Shutting down server...", slog.String("signal", sig.String()))
 
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
 	if err := srv.Shutdown(ctx); err != nil {
-		log.Fatalf("Server forced to shutdown: %v", err)
+		slog.Error("Server forced to shutdown", slog.Any("error", err))
+		return err
 	}
-	log.Println("Server shutdown successful!")
+
+	slog.Info("Service shutdown successful!")
+	return nil
 }