From 5903c6fbcd422f2e8eafcaa592927e2a0eb3d470 Mon Sep 17 00:00:00 2001
From: nxshock <nxshock@gmail.com>
Date: Fri, 29 Dec 2023 12:16:35 +0500
Subject: [PATCH] Implement reload config feature

---
 PKGBUILD  |  2 +-
 app.go    | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 config.go |  2 ++
 main.go   | 45 ++++++++++++++++----------------
 4 files changed, 102 insertions(+), 24 deletions(-)
 create mode 100644 app.go

diff --git a/PKGBUILD b/PKGBUILD
index 48e24d5..52a5275 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -1,5 +1,5 @@
 pkgname=gonx
-pkgver=0.0.2
+pkgver=0.0.3
 pkgrel=1
 pkgdesc='Simple reverse proxy server'
 arch=('x86_64' 'aarch64')
diff --git a/app.go b/app.go
new file mode 100644
index 0000000..745e85c
--- /dev/null
+++ b/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
+}
diff --git a/config.go b/config.go
index c6a2585..5671fe4 100644
--- a/config.go
+++ b/config.go
@@ -55,6 +55,8 @@ func LoadConfig(configFilePath string) (*Config, error) {
 }
 
 func (c *Config) initTls() error {
+	slog.Debug("Loading TLS keys")
+
 	c.tlsConfig = new(tls.Config)
 
 	for hostName := range c.proxyRules {
diff --git a/main.go b/main.go
index d2792d2..ec3811d 100644
--- a/main.go
+++ b/main.go
@@ -1,7 +1,6 @@
 package main
 
 import (
-	"crypto/tls"
 	"log/slog"
 	"net/http"
 	"os"
@@ -33,32 +32,17 @@ func main() {
 		}}))
 	slog.SetDefault(logger)
 
-	err = config.initTls()
+	app, err := newApp(config)
 	if err != nil {
-		slog.Error("init tls error", slog.String("err", err.Error()))
+		slog.Error("Failed to start app", slog.String("err", err.Error()))
 		os.Exit(1)
 	}
 
-	go func() {
-		slog.Debug("Starting TLS listener", slog.String("addr", config.TlsListenAddr))
-
-		listener, err := tls.Listen("tcp", config.TlsListenAddr, config.tlsConfig)
-		if err != nil {
-			slog.Error("Failed to open tls listener", slog.String("err", err.Error()))
-			os.Exit(1)
-		}
-
-		for {
-			conn, err := listener.Accept()
-			if err != nil {
-				slog.Debug("incoming connection failed", slog.String("err", err.Error()))
-				continue
-			}
-			slog.Debug("incoming connection", slog.String("RemoteAddr", conn.RemoteAddr().String()))
-
-			go func() { _ = handleTlsConn(conn.(*tls.Conn), config.proxyRules) }()
-		}
-	}()
+	err = app.restartTlsListener()
+	if err != nil {
+		slog.Error("Failed to start TLS listener", slog.String("err", err.Error()))
+		os.Exit(1)
+	}
 
 	go func() {
 		slog.Debug("Starting HTTP listener", slog.String("addr", config.HttpListenAddr))
@@ -77,6 +61,21 @@ func main() {
 		}
 	}()
 
+	go func() {
+		c := make(chan os.Signal, 1)
+		signal.Notify(c, syscall.SIGUSR1)
+		for {
+			<-c
+			slog.Debug("TLS keys reload requested")
+
+			err := app.reloadConfig(configFilePath)
+			if err != nil {
+				slog.Error("failed to reload TLS keys", slog.String("err", err.Error()))
+			}
+			slog.Debug("Reloading TLS keys completed")
+		}
+	}()
+
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
 	<-c