feat(go): add realtime pipeline observability

go/vehicle-gateway/internal/gateway/mqtt_client.go

@@ -197,6 +197,7 @@ func (c *MQTTClient) handleMessage(ctx context.Context, topic string, payload []
 			ParseError:     err.Error(),
 		}
 		env.EventID = env.StableEventID()
+		c.recordParseErrorMetric(err)
 	} else {
 		resolved, resolveErr := c.cfg.Resolver.Resolve(messageCtx, env)
 		if resolveErr != nil {
@@ -206,8 +207,11 @@ func (c *MQTTClient) handleMessage(ctx context.Context, topic string, payload []
 			}
 			env.Parsed["identity"] = map[string]any{"resolved": false, "error": resolveErr.Error()}
 			env.ParseStatus = envelope.ParsePartial
+			c.recordIdentityMetric("error")
 		} else {
 			env = resolved
+			annotateIdentityUnresolved(&env)
+			c.recordIdentityMetric(identityStatus(env))
 		}
 	}
 	c.recordFrameMetric(env.ParseStatus)
@@ -258,3 +262,23 @@ func (c *MQTTClient) recordPublishMetric(kind string, status string) {
 		"status":   status,
 	})
 }
+
+func (c *MQTTClient) recordParseErrorMetric(err error) {
+	if c.cfg.Metrics == nil {
+		return
+	}
+	c.cfg.Metrics.IncCounter("vehicle_gateway_parse_errors_total", metrics.Labels{
+		"protocol": string(envelope.ProtocolYutongMQTT),
+		"reason":   classifyError(err),
+	})
+}
+
+func (c *MQTTClient) recordIdentityMetric(status string) {
+	if c.cfg.Metrics == nil {
+		return
+	}
+	c.cfg.Metrics.IncCounter("vehicle_gateway_identity_total", metrics.Labels{
+		"protocol": string(envelope.ProtocolYutongMQTT),
+		"status":   status,
+	})
+}