refactor(app,logging,proxy,ssl): 改进错误处理，使用空白标识符忽略明确不关心的返回值

- 使用 _ 忽略 Close、Write、Signal 等函数的错误返回值
- 这些场景的错误处理没有实际意义（关闭时已处于清理阶段）
- 移除 health.go 中未使用的 mu 字段
- proxy 模块使用 for-range 替代 VisitAll 遍历头部

Co-Authored-By: Claude <noreply@anthropic.com>

internal/app/app.go

@@ -249,7 +249,7 @@ func (a *App) Run() int {
 	a.upgradeMgr = server.NewUpgradeManager(a.srv)
 	if a.pidFile != "" {
 		a.upgradeMgr.SetPidFile(a.pidFile)
-		a.upgradeMgr.WritePid()
+		_ = a.upgradeMgr.WritePid()
 	}
 
 	// 启动信号处理
@@ -301,14 +301,14 @@ func (a *App) handleSignal(sig os.Signal) bool {
 		// 优雅停止：等待请求完成
 		a.logger.LogSignal("SIGQUIT", fmt.Sprintf("优雅停止（等待 %v）", shutdownTimeout))
 		a.shutdownHTTP3()
-		a.srv.GracefulStop(shutdownTimeout)
+		_ = a.srv.GracefulStop(shutdownTimeout)
 		return false
 
 	case syscall.SIGTERM, syscall.SIGINT:
 		// 快速停止
 		a.logger.LogSignal(sigName(sig.(syscall.Signal)), "停止服务器")
 		a.shutdownHTTP3()
-		a.srv.Stop()
+		_ = a.srv.Stop()
 		return false
 
 	case syscall.SIGHUP:
@@ -398,7 +398,7 @@ func (a *App) gracefulUpgrade() {
 
 	// 当前进程优雅停止
 	a.shutdownHTTP3()
-	a.srv.GracefulStop(shutdownTimeout)
+	_ = a.srv.GracefulStop(shutdownTimeout)
 }
 
 // sigName 返回信号名称（用于日志输出）。

internal/logging/logging.go

@@ -124,7 +124,7 @@ func (l *Logger) LogAccess(ctx *fasthttp.RequestCtx, status int, size int64, dur
 
 	// 模板格式：直接输出纯文本
 	output := l.formatAccessLog(ctx, status, size, duration)
-	fmt.Fprintln(l.accessWriter, output)
+	_, _ = fmt.Fprintln(l.accessWriter, output)
 }
 
 // formatAccessLog 根据模板格式化访问日志。
@@ -179,10 +179,10 @@ func (l *Logger) Error() *zerolog.Event {
 // Close 关闭日志文件。
 func (l *Logger) Close() error {
 	if l.accessFile != nil {
-		l.accessFile.Close()
+		_ = l.accessFile.Close()
 	}
 	if l.errorFile != nil {
-		l.errorFile.Close()
+		_ = l.errorFile.Close()
 	}
 	return nil
 }
@@ -258,7 +258,7 @@ func (l *AppLogger) LogStartup(msg string, fields map[string]string) {
 	// 纯文本格式
 	timestamp := time.Now().Format("2006-01-02 15:04:05")
 	if len(fields) == 0 {
-		fmt.Fprintf(l.writer, "[%s] INFO %s\n", timestamp, msg)
+		_, _ = fmt.Fprintf(l.writer, "[%s] INFO %s\n", timestamp, msg)
 		return
 	}
 
@@ -267,7 +267,7 @@ func (l *AppLogger) LogStartup(msg string, fields map[string]string) {
 	for k, v := range fields {
 		extra += fmt.Sprintf(" %s=%s", k, v)
 	}
-	fmt.Fprintf(l.writer, "[%s] INFO %s%s\n", timestamp, msg, extra)
+	_, _ = fmt.Fprintf(l.writer, "[%s] INFO %s%s\n", timestamp, msg, extra)
 }
 
 // LogShutdown 记录停止消息。
@@ -278,7 +278,7 @@ func (l *AppLogger) LogShutdown(msg string) {
 	}
 
 	timestamp := time.Now().Format("2006-01-02 15:04:05")
-	fmt.Fprintf(l.writer, "[%s] INFO %s\n", timestamp, msg)
+	_, _ = fmt.Fprintf(l.writer, "[%s] INFO %s\n", timestamp, msg)
 }
 
 // LogSignal 记录信号处理消息。
@@ -289,7 +289,7 @@ func (l *AppLogger) LogSignal(sig string, action string) {
 	}
 
 	timestamp := time.Now().Format("2006-01-02 15:04:05")
-	fmt.Fprintf(l.writer, "[%s] INFO 收到 %s，%s\n", timestamp, sig, action)
+	_, _ = fmt.Fprintf(l.writer, "[%s] INFO 收到 %s，%s\n", timestamp, sig, action)
 }
 
 // Info 返回 Info 级别日志记录器。

internal/proxy/health.go

@@ -53,7 +53,6 @@ type HealthChecker struct {
 	stopCh   chan struct{}
 	running  atomic.Bool
 	client   *fasthttp.Client
-	mu       sync.RWMutex
 }
 
 // NewHealthChecker 使用指定的目标和配置创建一个新的 HealthChecker。

internal/proxy/proxy.go

@@ -293,9 +293,9 @@ func (p *Proxy) ServeHTTP(ctx *fasthttp.RequestCtx) {
 		if status >= 200 && status < 300 {
 			// 提取响应头
 			headers := make(map[string]string)
-			ctx.Response.Header.VisitAll(func(key, value []byte) {
+			for key, value := range ctx.Response.Header.All() {
 				headers[string(key)] = string(value)
-			})
+			}
 			p.cache.Set(cacheKey, ctx.Response.Body(), headers, status, p.config.Cache.MaxAge)
 		}
 		p.cache.ReleaseLock(cacheKey, nil)
@@ -555,9 +555,9 @@ func (p *Proxy) backgroundRefresh(ctx *fasthttp.RequestCtx, target *loadbalance.
 
 	// 提取响应头
 	headers := make(map[string]string)
-	resp.Header.VisitAll(func(key, value []byte) {
+	for key, value := range resp.Header.All() {
 		headers[string(key)] = string(value)
-	})
+	}
 
 	// 更新缓存
 	p.cache.Set(cacheKey, resp.Body(), headers, resp.StatusCode(), p.config.Cache.MaxAge)

internal/proxy/websocket.go

@@ -249,11 +249,11 @@ func dialTarget(targetURL string, timeout time.Duration) (net.Conn, error) {
 			ServerName:         strings.Split(addr, ":")[0],
 		})
 		if err := tlsConn.SetDeadline(time.Now().Add(timeout)); err != nil {
-			conn.Close()
+			_ = conn.Close()
 			return nil, fmt.Errorf("failed to set TLS deadline: %w", err)
 		}
 		if err := tlsConn.Handshake(); err != nil {
-			conn.Close()
+			_ = conn.Close()
 			return nil, fmt.Errorf("TLS handshake failed: %w", err)
 		}
 		return tlsConn, nil
@@ -390,7 +390,7 @@ func ProxyWebSocket(ctx *fasthttp.RequestCtx, target *loadbalance.Target, timeou
 	// 步骤1: 建立到后端目标的连接
 	targetConn, err := dialTarget(target.URL, timeout)
 	if err != nil {
-		clientConn.Close()
+		_ = clientConn.Close()
 		return fmt.Errorf("failed to connect to backend: %w", err)
 	}
 
@@ -400,30 +400,30 @@ func ProxyWebSocket(ctx *fasthttp.RequestCtx, target *loadbalance.Target, timeou
 	// 步骤3: 构建并发送 WebSocket 升级请求
 	upgradeReq := buildWebSocketUpgradeRequest(ctx, targetHost)
 	if _, err := targetConn.Write([]byte(upgradeReq)); err != nil {
-		clientConn.Close()
+		_ = clientConn.Close()
-		targetConn.Close()
+		_ = targetConn.Close()
 		return fmt.Errorf("failed to send upgrade request: %w", err)
 	}
 
 	// 步骤4: 读取升级响应
 	resp, err := readWebSocketUpgradeResponse(targetConn, timeout)
 	if err != nil {
-		clientConn.Close()
+		_ = clientConn.Close()
-		targetConn.Close()
+		_ = targetConn.Close()
 		return fmt.Errorf("failed to read upgrade response: %w", err)
 	}
 
 	// 步骤5: 检查响应状态码（期望 101 Switching Protocols）
 	if resp.StatusCode != http.StatusSwitchingProtocols {
-		clientConn.Close()
+		_ = clientConn.Close()
-		targetConn.Close()
+		_ = targetConn.Close()
 		return fmt.Errorf("backend rejected WebSocket upgrade: %s", resp.Status)
 	}
 
 	// 步骤6: 将升级响应发送回客户端
 	if err := writeUpgradeResponse(clientConn, resp); err != nil {
-		clientConn.Close()
+		_ = clientConn.Close()
-		targetConn.Close()
+		_ = targetConn.Close()
 		return fmt.Errorf("failed to send upgrade response to client: %w", err)
 	}
 
@@ -434,7 +434,7 @@ func ProxyWebSocket(ctx *fasthttp.RequestCtx, target *loadbalance.Target, timeou
 	bridgeErr := bridge.Bridge()
 
 	// 清理：关闭连接
-	bridge.Close()
+	_ = bridge.Close()
 
 	return bridgeErr
 }

internal/ssl/ocsp.go

@@ -327,7 +327,7 @@ func (m *OCSPManager) sendOCSPRequest(url string, req []byte) ([]byte, error) {
 			}
 			return nil, fmt.Errorf("HTTP request failed: %w", err)
 		}
-		defer resp.Body.Close()
+		defer func() { _ = resp.Body.Close() }()
 
 		if resp.StatusCode != http.StatusOK {
 			if i < m.maxRetries-1 {

internal/ssl/ssl.go

@@ -152,7 +152,7 @@ func NewTLSManager(cfg *config.SSLConfig) (*TLSManager, error) {
 						manager.issuers[serial] = issuerCert
 						// 注册证书用于 OCSP Stapling
 						// 错误会记录日志但不会阻止 TLS 工作
-						ocspMgr.RegisterCertificate(parsedCert, issuerCert)
+						_ = ocspMgr.RegisterCertificate(parsedCert, issuerCert)
 					}
 				}