Implement reload config feature

app.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"crypto/tls"
+	"fmt"
+	"log/slog"
+	"net"
+)
+
+type App struct {
+	config      *Config
+	tlsListener net.Listener
+}
+
+func newApp(config *Config) (*App, error) {
+	err := config.initTls()
+	if err != nil {
+		return nil, fmt.Errorf("failed to load TLS keys: %v", err)
+	}
+
+	app := &App{config: config}
+
+	return app, nil
+}
+
+func (app *App) reloadConfig(configFilePath string) error {
+	config, err := LoadConfig(configFilePath)
+	if err != nil {
+		return fmt.Errorf("failed to load config: %v", err)
+	}
+
+	err = config.initTls()
+	if err != nil {
+		return fmt.Errorf("failed to load TLS keys: %v", err)
+	}
+
+	app.config = config
+
+	slog.Debug("Deactivating TLS listener", slog.String("addr", app.config.TlsListenAddr))
+	err = app.tlsListener.Close()
+	if err != nil {
+		return fmt.Errorf("failed to close TLS listener: %v", err)
+	}
+
+	err = app.restartTlsListener()
+	if err != nil {
+		return fmt.Errorf("failed to restart TLS listener: %v", err)
+	}
+
+	return nil
+}
+
+func (app *App) restartTlsListener() error {
+	slog.Debug("Starting TLS listener", slog.String("addr", app.config.TlsListenAddr))
+
+	tlsListener, err := tls.Listen("tcp", app.config.TlsListenAddr, app.config.tlsConfig)
+	if err != nil {
+		return fmt.Errorf("failed to open tls listener: %v", err)
+	}
+
+	app.tlsListener = tlsListener
+
+	go func() {
+		for {
+			conn, err := tlsListener.Accept()
+			if err != nil {
+				slog.Error("failed to receive connection", slog.String("err", err.Error())) // TODO: drop error on closing TLS listener
+				break
+			}
+			slog.Debug("incoming connection", slog.String("RemoteAddr", conn.RemoteAddr().String()))
+
+			go func() { _ = handleTlsConn(conn.(*tls.Conn), app.config.proxyRules) }()
+		}
+	}()
+
+	return nil
+}