auto restart server

cmd/byre/serve.go

@@ -39,6 +39,9 @@ func serveCmd(args []string) {
 
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
 	defer stop()
+	ctx, replaced := context.WithCancel(ctx)
+	defer replaced()
+	go watchExecutable(ctx, replaced)
 
 	hs := &http.Server{
 		Addr:        *listenAddr,
@@ -59,3 +62,33 @@ func serveCmd(args []string) {
 		fatal("serve", "err", err)
 	}
 }
+
+func watchExecutable(ctx context.Context, replaced context.CancelFunc) {
+	exe, err := os.Executable()
+	if err != nil {
+		fatal("executable path", "err", err)
+	}
+	started, err := os.Stat(exe)
+	if err != nil {
+		fatal("stat executable", "path", exe, "err", err)
+	}
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+		}
+		now, err := os.Stat(exe)
+		if err != nil {
+			continue
+		}
+		if os.SameFile(started, now) {
+			continue
+		}
+		slog.Info("executable replaced, exiting", "path", exe)
+		replaced()
+		return
+	}
+}