fix: fix oom risk

Author: fishtailfu

polaris-plugins/polaris-plugins-connector/connector-nacos/src/main/java/com/tencent/polaris/plugins/connector/nacos/NacosConnector.java

@@ -253,7 +253,30 @@ public CommonProviderResponse registerInstance(CommonProviderRequest req,
         }
         return response;
     }
+    @Override
+    public void deregisterInstance(CommonProviderRequest req) throws PolarisException {
+
+        try {
+            NamingService service = getOrCreateNacosService(req.getNamespace()).getNamingService();
+            if (service == null) {
+                LOG.error("nacos client fail to lookup namingService for service {}", req.getService());
+                return;
+            }
+            // 优先设置成nacos的service name，如没有再设置成req的service name
 
+            Instance instance = buildDeregisterNacosInstance(req);
+            // deregister with nacos naming service
+            service.deregisterInstance(instance.getServiceName(), nacosContext.getGroupName(),
+                    instance);
+            LOG.info("nacos client deregister service {} success, groupName: {}, clusterName: {}, instance: {}",
+                    instance.getServiceName(), nacosContext.getGroupName(), nacosContext.getClusterName(), instance);
+        } catch (NacosException e) {
+            throw new RetriableException(ErrorCode.NETWORK_ERROR,
+                    String.format("nacos fail to deregister host %s:%d service %s", req.getHost(),
+                            req.getPort(),
+                            req.getService()), e);
+        }
+    }
     @Override
     public void heartbeat(CommonProviderRequest req) throws PolarisException {
         // do nothing
@@ -369,31 +392,6 @@ private Instance buildRegisterNacosInstance(CommonProviderRequest req) {
         return instance;
     }
 
-    @Override
-    public void deregisterInstance(CommonProviderRequest req) throws PolarisException {
-
-        try {
-            NamingService service = getOrCreateNacosService(req.getNamespace()).getNamingService();
-            if (service == null) {
-                LOG.error("nacos client fail to lookup namingService for service {}", req.getService());
-                return;
-            }
-            // 优先设置成nacos的service name，如没有再设置成req的service name
-
-            Instance instance = buildDeregisterNacosInstance(req);
-            // deregister with nacos naming service
-            service.deregisterInstance(instance.getServiceName(), nacosContext.getGroupName(),
-                    instance);
-            LOG.info("nacos client deregister service {} success, groupName: {}, clusterName: {}, instance: {}",
-                    instance.getServiceName(), nacosContext.getGroupName(), nacosContext.getClusterName(), instance);
-        } catch (NacosException e) {
-            throw new RetriableException(ErrorCode.NETWORK_ERROR,
-                    String.format("nacos fail to deregister host %s:%d service %s", req.getHost(),
-                            req.getPort(),
-                            req.getService()), e);
-        }
-    }
-
     private String getServiceName(CommonProviderRequest req) {
         // nacos上注册和polaris不同的服务名时优先用nacosContext中的serviceName
         String serviceName = req.getService();