init

cmd/server/main.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"github.com/wzray/dns/internal/resolv"
+	"github.com/wzray/dns/internal/server"
+)
+
+func main() {
+	addr := flag.String("addr", ":8080", "HTTP listen address")
+	logLevel := flag.String("log-level", "info", "Log level: debug, info, warn, error")
+	logFormat := flag.String("log-format", "text", "Log format: text or json")
+	flag.Parse()
+
+	log := newLogger(*logLevel, *logFormat)
+
+	resolvPath := resolv.DefaultPath
+	if err := os.MkdirAll(filepath.Dir(resolvPath), 0o755); err != nil {
+		log.Error("prepare resolv directory", "err", err)
+		os.Exit(1)
+	}
+
+	mgr := resolv.New(resolvPath)
+	srv := server.New(mgr, log)
+
+	httpSrv := &http.Server{
+		Addr:              *addr,
+		Handler:           srv.Handler(),
+		ReadHeaderTimeout: 5 * time.Second,
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	errCh := make(chan error, 1)
+	go func() {
+		log.Info("starting server", "addr", *addr)
+		if err := httpSrv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			errCh <- err
+		}
+	}()
+
+	select {
+	case <-ctx.Done():
+		log.Info("shutting down")
+	case err := <-errCh:
+		log.Error("server error", "err", err)
+		os.Exit(1)
+	}
+
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	if err := httpSrv.Shutdown(shutdownCtx); err != nil {
+		log.Error("graceful shutdown failed", "err", err)
+		os.Exit(1)
+	}
+}
+
+func newLogger(level, format string) *slog.Logger {
+	var lvl slog.Level
+	switch level {
+	case "debug":
+		lvl = slog.LevelDebug
+	case "warn":
+		lvl = slog.LevelWarn
+	case "error":
+		lvl = slog.LevelError
+	default:
+		lvl = slog.LevelInfo
+	}
+	opts := &slog.HandlerOptions{Level: lvl}
+	var h slog.Handler
+	if format == "json" {
+		h = slog.NewJSONHandler(os.Stderr, opts)
+	} else {
+		h = slog.NewTextHandler(os.Stderr, opts)
+	}
+	return slog.New(h)
+}