fix: add nacos catalog fallback

monitor/nacos.py

@@ -329,6 +329,25 @@ def list_instances(namespace_id: str, service_name: str, group_name: str) -> lis
     return list(payload.get("hosts") or [])
 
 
+def catalog_instances(namespace_id: str, service_name: str, group_name: str) -> list[dict[str, Any]]:
+    # 调用 catalog/instances 获取注册表视图。
+    payload = nacos_request(
+        "GET",
+        "/nacos/v1/ns/catalog/instances",
+        {
+            "serviceName": service_name,
+            "groupName": group_name,
+            "namespaceId": namespace_id or None,
+            "clusterName": NACOS_DISCOVERY_CLUSTER_NAME,
+            "pageNo": "1",
+            "pageSize": str(max(NACOS_PAGE_SIZE, 200)),
+        },
+    )
+
+    # 返回 list 字段。
+    return list(payload.get("list") or [])
+
+
 def build_service_level(instance_total: int, healthy_total: int, enabled_total: int) -> str:
     # 没有实例时直接标 bad。
     if instance_total == 0:
@@ -422,6 +441,14 @@ def build_nacos_payload() -> dict[str, Any]:
         for query in queries_by_key.values():
             # 拉取当前服务实例。
             instance_items = list_instances(namespace["namespaceId"], query["registryName"], query["groupName"])
+
+            # 常规实例接口为空时，再走 catalog 视图兜底。
+            if not instance_items:
+                instance_items = catalog_instances(
+                    namespace["namespaceId"],
+                    query["registryName"],
+                    query["groupName"],
+                )
             # 归一化实例结构。
             normalized_instances: list[dict[str, Any]] = []