[hw-7] add metrics, tracing

loms/internal/app/app.go

@@ -11,6 +11,7 @@ import (
 	"github.com/IBM/sarama"
 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
 	"google.golang.org/grpc"
@@ -22,9 +23,9 @@ import (
 	stocksRepository "route256/loms/internal/domain/repository/stocks/sqlc"
 	"route256/loms/internal/domain/service"
 	"route256/loms/internal/infra/config"
+	"route256/loms/internal/infra/db/postgres"
 	mw "route256/loms/internal/infra/grpc/middleware"
 	"route256/loms/internal/infra/messaging/kafka"
-	"route256/loms/internal/infra/postgres"
 
 	pb "route256/pkg/api/loms/v1"
 )
@@ -134,7 +135,9 @@ func (app *App) ListenAndServe(ctx context.Context) error {
 
 	app.grpcServer = grpc.NewServer(
 		grpc.ChainUnaryInterceptor(
+			mw.WithTracing,
 			mw.Logging,
+			mw.WithMetrics,
 			mw.Validate,
 		),
 	)
@@ -166,9 +169,13 @@ func (app *App) ListenAndServe(ctx context.Context) error {
 		return fmt.Errorf("pb.RegisterLOMSHandler: %w", err)
 	}
 
+	root := http.NewServeMux()
+	root.Handle("/metrics", promhttp.Handler())
+	root.Handle("/", gwmux)
+
 	app.httpServer = &http.Server{
 		Addr:        fmt.Sprintf("%s:%s", app.config.Service.Host, app.config.Service.HTTPPort),
-		Handler:     gwmux,
+		Handler:     root,
 		ReadTimeout: 10 * time.Second,
 	}