feat(go): improve realtime pipeline resilience

go/vehicle-gateway/internal/gateway/tcp_server.go

@@ -195,6 +195,12 @@ func (s *TCPServer) handleConnection(ctx context.Context, conn net.Conn) {
 }
 
 func (s *TCPServer) handleFrame(ctx context.Context, conn net.Conn, raw []byte, source string, state *connectionState) {
+	started := time.Now()
+	frameStatus := envelope.ParseBadFrame
+	defer func() {
+		s.recordFrameDuration(frameStatus, time.Since(started))
+	}()
+
 	frameCtx, cancelFrame := context.WithTimeout(context.WithoutCancel(ctx), frameOperationTimeout)
 	defer cancelFrame()
 
@@ -229,6 +235,7 @@ func (s *TCPServer) handleFrame(ctx context.Context, conn net.Conn, raw []byte,
 		}
 		enrichConnectionPlatform(&env, state)
 	}
+	frameStatus = env.ParseStatus
 	s.recordFrameMetric(env.ParseStatus)
 
 	if err := s.sink.PublishRaw(frameCtx, env); err != nil {
@@ -307,6 +314,16 @@ func (s *TCPServer) recordFrameMetric(status envelope.ParseStatus) {
 	})
 }
 
+func (s *TCPServer) recordFrameDuration(status envelope.ParseStatus, elapsed time.Duration) {
+	if s.metrics == nil {
+		return
+	}
+	s.metrics.SetGauge("vehicle_gateway_frame_duration_ms", metrics.Labels{
+		"protocol": string(s.protocol.Protocol),
+		"status":   string(status),
+	}, float64(elapsed.Milliseconds()))
+}
+
 func (s *TCPServer) recordPublishMetric(kind string, status string) {
 	if s.metrics == nil {
 		return