func main()

in src/frontend/main.go [90:171]
72 lines of code
4 McCabe index (conditional complexity)

func main() {
	ctx := context.Background()
	log := logrus.New()
	log.Level = logrus.DebugLevel
	log.Formatter = &logrus.JSONFormatter{
		FieldMap: logrus.FieldMap{
			logrus.FieldKeyTime:  "timestamp",
			logrus.FieldKeyLevel: "severity",
			logrus.FieldKeyMsg:   "message",
		},
		TimestampFormat: time.RFC3339Nano,
	}
	log.Out = os.Stdout

	svc := new(frontendServer)

	otel.SetTextMapPropagator(
		propagation.NewCompositeTextMapPropagator(
			propagation.TraceContext{}, propagation.Baggage{}))

	baseUrl = os.Getenv("BASE_URL")

	if os.Getenv("ENABLE_TRACING") == "1" {
		log.Info("Tracing enabled.")
		initTracing(log, ctx, svc)
	} else {
		log.Info("Tracing disabled.")
	}

	if os.Getenv("ENABLE_PROFILER") == "1" {
		log.Info("Profiling enabled.")
		go initProfiling(log, "frontend", "1.0.0")
	} else {
		log.Info("Profiling disabled.")
	}

	srvPort := port
	if os.Getenv("PORT") != "" {
		srvPort = os.Getenv("PORT")
	}
	addr := os.Getenv("LISTEN_ADDR")
	mustMapEnv(&svc.productCatalogSvcAddr, "PRODUCT_CATALOG_SERVICE_ADDR")
	mustMapEnv(&svc.currencySvcAddr, "CURRENCY_SERVICE_ADDR")
	mustMapEnv(&svc.cartSvcAddr, "CART_SERVICE_ADDR")
	mustMapEnv(&svc.recommendationSvcAddr, "RECOMMENDATION_SERVICE_ADDR")
	mustMapEnv(&svc.checkoutSvcAddr, "CHECKOUT_SERVICE_ADDR")
	mustMapEnv(&svc.shippingSvcAddr, "SHIPPING_SERVICE_ADDR")
	mustMapEnv(&svc.adSvcAddr, "AD_SERVICE_ADDR")
	mustMapEnv(&svc.shoppingAssistantSvcAddr, "SHOPPING_ASSISTANT_SERVICE_ADDR")

	mustConnGRPC(ctx, &svc.currencySvcConn, svc.currencySvcAddr)
	mustConnGRPC(ctx, &svc.productCatalogSvcConn, svc.productCatalogSvcAddr)
	mustConnGRPC(ctx, &svc.cartSvcConn, svc.cartSvcAddr)
	mustConnGRPC(ctx, &svc.recommendationSvcConn, svc.recommendationSvcAddr)
	mustConnGRPC(ctx, &svc.shippingSvcConn, svc.shippingSvcAddr)
	mustConnGRPC(ctx, &svc.checkoutSvcConn, svc.checkoutSvcAddr)
	mustConnGRPC(ctx, &svc.adSvcConn, svc.adSvcAddr)

	r := mux.NewRouter()
	r.HandleFunc(baseUrl + "/", svc.homeHandler).Methods(http.MethodGet, http.MethodHead)
	r.HandleFunc(baseUrl + "/product/{id}", svc.productHandler).Methods(http.MethodGet, http.MethodHead)
	r.HandleFunc(baseUrl + "/cart", svc.viewCartHandler).Methods(http.MethodGet, http.MethodHead)
	r.HandleFunc(baseUrl + "/cart", svc.addToCartHandler).Methods(http.MethodPost)
	r.HandleFunc(baseUrl + "/cart/empty", svc.emptyCartHandler).Methods(http.MethodPost)
	r.HandleFunc(baseUrl + "/setCurrency", svc.setCurrencyHandler).Methods(http.MethodPost)
	r.HandleFunc(baseUrl + "/logout", svc.logoutHandler).Methods(http.MethodGet)
	r.HandleFunc(baseUrl + "/cart/checkout", svc.placeOrderHandler).Methods(http.MethodPost)
	r.HandleFunc(baseUrl + "/assistant", svc.assistantHandler).Methods(http.MethodGet)
	r.PathPrefix(baseUrl + "/static/").Handler(http.StripPrefix(baseUrl + "/static/", http.FileServer(http.Dir("./static/"))))
	r.HandleFunc(baseUrl + "/robots.txt", func(w http.ResponseWriter, _ *http.Request) { fmt.Fprint(w, "User-agent: *\nDisallow: /") })
	r.HandleFunc(baseUrl + "/_healthz", func(w http.ResponseWriter, _ *http.Request) { fmt.Fprint(w, "ok") })
	r.HandleFunc(baseUrl + "/product-meta/{ids}", svc.getProductByID).Methods(http.MethodGet)
	r.HandleFunc(baseUrl + "/bot", svc.chatBotHandler).Methods(http.MethodPost)

	var handler http.Handler = r
	handler = &logHandler{log: log, next: handler}     // add logging
	handler = ensureSessionID(handler)                 // add session ID
	handler = otelhttp.NewHandler(handler, "frontend") // add OTel tracing

	log.Infof("starting server on " + addr + ":" + srvPort)
	log.Fatal(http.ListenAndServe(addr+":"+srvPort, handler))
}