Implement rudimentary link shortening service and wire everything together

main.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+	"context"
+	"log/slog"
+	"net/http"
+	"os"
+
+	"connectrpc.com/connect"
+	"connectrpc.com/grpcreflect"
+	"connectrpc.com/validate"
+	"git.kocoder.xyz/vt/shortener/internal/config"
+	"git.kocoder.xyz/vt/shortener/internal/database"
+	"git.kocoder.xyz/vt/shortener/internal/proto/shorten/v1/shortenv1connect"
+	"git.kocoder.xyz/vt/shortener/internal/service"
+	"git.kocoder.xyz/vt/shortener/internal/telemetry"
+	_ "github.com/lib/pq"
+	"github.com/uptrace/opentelemetry-go-extra/otelsql"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+	"go.opentelemetry.io/otel/attribute"
+)
+
+func main() {
+	// Fallback logger for early startup errors
+	slog.SetDefault(slog.New(slog.NewJSONHandler(os.Stdout, nil)))
+
+	conf := config.Read()
+
+	ctx := context.Background()
+	shutdown, err := telemetry.Init(ctx, conf.OTLP_ENDPOINT, "shortener-server")
+	if err != nil {
+		slog.Error("Failed to initialize telemetry", slog.String("err", err.Error()))
+	}
+	defer func() {
+		if err := shutdown(ctx); err != nil {
+			slog.Error("Error shutting down telemetry", slog.String("err", err.Error()))
+		}
+	}()
+
+	// Connect to DB and wrap with otelsql for database tracing
+	db, err := otelsql.Open("postgres", conf.DB_URL)
+	if err != nil {
+		slog.Error("failed to connect to database", slog.String("err", err.Error()))
+		os.Exit(1)
+	}
+	defer db.Close()
+
+	otelsql.ReportDBStatsMetrics(db, otelsql.WithAttributes(
+		attribute.String("db.system", "postgresql"),
+	))
+
+	dbQueries := database.New(db)
+
+	srv := service.NewServer(conf, dbQueries)
+
+	mux := http.NewServeMux()
+	path, handler := shortenv1connect.NewShortenServiceHandler(
+		service.NewShortenerService(conf, dbQueries),
+		connect.WithInterceptors(validate.NewInterceptor()),
+	)
+	mux.Handle(path, handler)
+
+	reflector := grpcreflect.NewStaticReflector(shortenv1connect.ShortenServiceName)
+	mux.Handle(grpcreflect.NewHandlerV1(reflector))
+	mux.Handle(grpcreflect.NewHandlerV1Alpha(reflector))
+
+	mux.Handle("/", srv)
+
+	// Wrap the server with OpenTelemetry HTTP handler for tracing & metrics
+	instrumentedHandler := otelhttp.NewHandler(mux, "shortener-server2")
+
+	p := new(http.Protocols)
+	p.SetHTTP1(true)
+	// Use h2c so we can serve HTTP/2 without TLS.
+	p.SetUnencryptedHTTP2(true)
+	s := http.Server{
+		Addr:      ":3001",
+		Handler:   instrumentedHandler,
+		Protocols: p,
+	}
+
+	slog.Info("Starting server on :3001")
+	if err := s.ListenAndServe(); err != nil {
+		slog.Error("Server failed", slog.String("err", err.Error()))
+	}
+}