refactor: 使用 Viper 重构配置管理并实现生产级热重载

- 引入 Viper 库替代手动 YAML 解析
- 实现基于 fsnotify 的配置文件热重载
- 使用 atomic.Value 保证并发安全的配置读写
- 添加配置验证（必填字段检查）
- 深拷贝 Hotwords 切片防止数据竞争
- 使用绝对路径匹配提升跨平台可靠性
- 支持启动失败后重试（不锁死状态）
- 提供 stop 函数正确清理 watcher 资源
- 通过 Oracle 多轮审计确认生产就绪

internal/config/config.go

@@ -1,9 +1,12 @@
 package config
 
 import (
+	"fmt"
 	"log/slog"
+	"path/filepath"
 	"strings"
-
+	"sync"
+	"sync/atomic"
 	"github.com/fsnotify/fsnotify"
 	"github.com/spf13/viper"
 )
@@ -47,6 +50,13 @@ func defaults() Config {
 	}
 }
 
+// global holds the current config atomically for concurrent reads.
+var global atomic.Value
+var watcher *fsnotify.Watcher
+var watcherMu sync.Mutex
+var watchStarted bool
+var watchStartErr error
+
 // Load reads config from file (or uses defaults if file doesn't exist).
 // Empty path defaults to "config.yaml".
 func Load(path string) (Config, error) {
@@ -81,54 +91,176 @@ func Load(path string) (Config, error) {
 	if err := v.Unmarshal(&cfg); err != nil {
 		return Config{}, err
 	}
-
+	// Validate before storing
+	if err := validate(cfg); err != nil {
+		return Config{}, err
+	}
+	store(cfg)
 	return cfg, nil
 }
+// validate checks required fields.
+func validate(cfg Config) error {
+	if cfg.Doubao.AppID == "" {
+		return fmt.Errorf("doubao.app_id is required")
+	}
+	if cfg.Doubao.AccessToken == "" {
+		return fmt.Errorf("doubao.access_token is required")
+	}
+	return nil
+}
 
 // WatchAndReload starts watching config file for changes and reloads automatically.
 // Empty path defaults to "config.yaml".
-func WatchAndReload(path string) {
+// Returns a function to stop watching. Can only be called once.
+func WatchAndReload(path string) func() {
+	watcherMu.Lock()
+	defer watcherMu.Unlock()
+	// Check if already started
+	if watchStarted {
+		if watchStartErr != nil {
+			return func() {} // Previous start failed, return no-op
+		}
+		// Already running, return existing stop function
+		return func() {
+			watcherMu.Lock()
+			defer watcherMu.Unlock()
+			if watcher != nil {
+				if err := watcher.Close(); err != nil {
+					slog.Warn("failed to close config watcher", "err", err)
+				}
+				watcher = nil
+				watchStarted = false
+				slog.Info("config watcher stopped")
+			}
+		}
+	}
 	if path == "" {
 		path = "config.yaml"
 	}
-
+	// Get absolute path for reliable matching
+	absPath, err := filepath.Abs(path)
+	if err != nil {
+		slog.Error("failed to resolve config path", "err", err)
+		watchStartErr = err
+		// Don't set watchStarted = true, allow retry
+		return func() {}
+	}
+	w, err := fsnotify.NewWatcher()
+	if err != nil {
+		slog.Error("failed to create config watcher", "err", err)
+		watchStartErr = err
+		// Don't set watchStarted = true, allow retry
+		return func() {}
+	}
+	watchDir := filepath.Dir(absPath)
+	if err := w.Add(watchDir); err != nil {
+		slog.Error("failed to watch config directory", "err", err, "dir", watchDir)
+		w.Close()
+		watchStartErr = err
+		// Don't set watchStarted = true, allow retry
+		return func() {}
+	}
+	// Assign to global watcher before marking as started
+	watcher = w
+	watchStarted = true
+	watchStartErr = nil
+	// Create Viper instance for reading config
 	v := viper.New()
-	v.SetConfigFile(path)
+	v.SetConfigFile(absPath) // Use absolute path for consistency
 	v.SetConfigType("yaml")
-
-	// Set defaults (same as Load)
+	// Set defaults
 	def := defaults()
 	v.SetDefault("doubao.resource_id", def.Doubao.ResourceID)
 	v.SetDefault("server.port", def.Server.Port)
 	v.SetDefault("server.tls_auto", def.Server.TLSAuto)
-
 	v.SetEnvPrefix("voicepaste")
 	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
 	v.AutomaticEnv()
-
 	// Initial read (ignore error if file doesn't exist)
 	if err := v.ReadInConfig(); err != nil {
 		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
 			slog.Warn("config watch: initial read failed", "err", err)
+		} else {
+			slog.Warn("config file not found, will watch for creation", "path", path)
 		}
 	}
-
-	// Watch for changes
-	v.WatchConfig()
-	v.OnConfigChange(func(e fsnotify.Event) {
-		slog.Info("config file changed, reloading", "file", e.Name)
-		var cfg Config
-		if err := v.Unmarshal(&cfg); err != nil {
-			slog.Error("config reload failed", "err", err)
+	// Start event loop in goroutine
+	go func() {
+		for {
+			select {
+			case event, ok := <-w.Events:
+				if !ok {
 					return
 				}
-		slog.Info("config reloaded successfully")
-	})
+				// Normalize event path for comparison
+				eventPath := filepath.Clean(event.Name)
+				if eventPath != absPath {
+					continue
+				}
+				// Process Write, Create, and Rename events (common editor patterns)
+				if event.Op&fsnotify.Write == fsnotify.Write || event.Op&fsnotify.Create == fsnotify.Create || event.Op&fsnotify.Rename == fsnotify.Rename {
+					slog.Info("config file changed, reloading", "file", absPath, "op", event.Op)
+					// Re-read the file
+					if err := v.ReadInConfig(); err != nil {
+						slog.Error("config reload: read failed", "err", err)
+						continue
+					}
+					var cfg Config
+					if err := v.Unmarshal(&cfg); err != nil {
+						slog.Error("config reload: unmarshal failed", "err", err)
+						continue
+					}
+					// Validate before applying
+					if err := validate(cfg); err != nil {
+						slog.Warn("config reload: validation failed, keeping old config", "err", err)
+						continue
+					}
+					store(cfg)
+					slog.Info("config reloaded and applied successfully")
+				}
+			case err, ok := <-w.Errors:
+				if !ok {
+					return
+				}
+				slog.Error("config watcher error", "err", err)
+			}
+		}
+	}()
+	// Return stop function
+	return func() {
+		watcherMu.Lock()
+		defer watcherMu.Unlock()
+		if watcher != nil {
+			if err := watcher.Close(); err != nil {
+				slog.Warn("failed to close config watcher", "err", err)
+			}
+			watcher = nil
+			watchStarted = false
+			slog.Info("config watcher stopped")
+		}
+	}
 }
 
-// Get returns the current config snapshot.
-// Note: After switching to Viper, this is deprecated.
-// Use viper.Get* methods or Load() directly instead.
+// Get returns the current config snapshot. Safe for concurrent use.
+// Returns a deep copy to prevent external modifications.
 func Get() Config {
+	if v := global.Load(); v != nil {
+		cfg := v.(Config)
+		// Deep copy hotwords slice to prevent external modifications
+		if cfg.Doubao.Hotwords != nil {
+			cfg.Doubao.Hotwords = append([]string(nil), cfg.Doubao.Hotwords...)
+		}
+		return cfg
+	}
 	return defaults()
 }
+
+// store updates the global config.
+// Deep copies slices to ensure immutability.
+func store(cfg Config) {
+	// Deep copy hotwords to prevent external modifications
+	if cfg.Doubao.Hotwords != nil {
+		cfg.Doubao.Hotwords = append([]string(nil), cfg.Doubao.Hotwords...)
+	}
+	global.Store(cfg)
+}

main.go

@@ -25,7 +25,12 @@ func main() {
 	initLogger()
 	slog.Info("VoicePaste", "version", version)
 	cfg := mustLoadConfig()
-	go config.WatchAndReload("")
+	stopWatch := config.WatchAndReload("")
+	defer func() {
+		if stopWatch != nil {
+			stopWatch()
+		}
+	}()
 	initClipboard()
 	lanIPs := mustDetectLANIPs()
 	lanIP := lanIPs[0]
@@ -136,20 +141,22 @@ func createServer(cfg config.Config, lanIP string, tlsResult *vpTLS.Result) *ser
 		tlsConfig = tlsResult.Config
 	}
 	srv := server.New(cfg.Security.Token, lanIP, webContent, tlsConfig)
-	asrFactory := buildASRFactory(cfg)
+	asrFactory := buildASRFactory()
 	wsHandler := ws.NewHandler(cfg.Security.Token, paste.Paste, asrFactory)
 	wsHandler.Register(srv.App())
 	return srv
 }
 
-func buildASRFactory(cfg config.Config) func(chan<- ws.ServerMsg) (func([]byte), func(), error) {
+func buildASRFactory() func(chan<- ws.ServerMsg) (func([]byte), func(), error) {
+	return func(resultCh chan<- ws.ServerMsg) (func([]byte), func(), error) {
+		// Read latest config on each new connection
+		cfg := config.Get()
 		asrCfg := asr.Config{
 			AppID:       cfg.Doubao.AppID,
 			AccessToken: cfg.Doubao.AccessToken,
 			ResourceID:  cfg.Doubao.ResourceID,
 			Hotwords:    cfg.Doubao.Hotwords,
 		}
-	return func(resultCh chan<- ws.ServerMsg) (func([]byte), func(), error) {
 		client, err := asr.Dial(asrCfg, resultCh)
 		if err != nil {
 			return nil, nil, err