[ISSUE#12644] Return cached instances when getAllInstance with subscr…

…ibe exception (#12929)

* when get cached all instance with `subscribe` exception, will return cached instance not throw exception.

* For checkstyle

client/src/main/java/com/alibaba/nacos/client/naming/NacosNamingService.java

@@ -24,6 +24,8 @@
 import com.alibaba.nacos.api.naming.pojo.Instance;
 import com.alibaba.nacos.api.naming.pojo.ListView;
 import com.alibaba.nacos.api.naming.pojo.ServiceInfo;
+import com.alibaba.nacos.api.naming.selector.NamingContext;
+import com.alibaba.nacos.api.naming.selector.NamingResult;
 import com.alibaba.nacos.api.naming.selector.NamingSelector;
 import com.alibaba.nacos.api.naming.utils.NamingUtils;
 import com.alibaba.nacos.api.selector.AbstractSelector;
@@ -37,6 +39,7 @@
 import com.alibaba.nacos.client.naming.remote.NamingClientProxyDelegate;
 import com.alibaba.nacos.client.naming.selector.NamingSelectorFactory;
 import com.alibaba.nacos.client.naming.selector.NamingSelectorWrapper;
+import com.alibaba.nacos.client.naming.selector.ServiceInfoContext;
 import com.alibaba.nacos.client.naming.utils.CollectionUtils;
 import com.alibaba.nacos.client.naming.utils.InitUtils;
 import com.alibaba.nacos.client.naming.utils.UtilAndComs;
@@ -324,38 +327,67 @@ private List<Instance> selectInstances(ServiceInfo serviceInfo, boolean healthy)
         return list;
     }
 
-    private ServiceInfo getServiceInfoByFailover(String serviceName, String groupName, String clusterString) {
-        return serviceInfoHolder.getFailoverServiceInfo(serviceName, groupName, clusterString);
+    private ServiceInfo getServiceInfo(String serviceName, String groupName, List<String> clusters, boolean subscribe)
+            throws NacosException {
+        ServiceInfo serviceInfo;
+        NamingSelector clusterSelector = NamingSelectorFactory.newClusterSelector(clusters);
+        if (serviceInfoHolder.isFailoverSwitch()) {
+            serviceInfo = getServiceInfoByFailover(serviceName, groupName, clusterSelector);
+            if (serviceInfo != null && !serviceInfo.getHosts().isEmpty()) {
+                NAMING_LOGGER.debug("getServiceInfo from failover,serviceName: {}  data:{}", serviceName,
+                        JacksonUtils.toJson(serviceInfo.getHosts()));
+                return serviceInfo;
+            }
+        }
+        serviceInfo = getServiceInfoBySubscribe(serviceName, groupName, clusters, clusterSelector, subscribe);
+        return serviceInfo;
     }
 
-    private ServiceInfo getServiceInfoBySubscribe(String serviceName, String groupName, String clusterString,
-            boolean subscribe) throws NacosException {
+    private ServiceInfo getServiceInfoByFailover(String serviceName, String groupName, NamingSelector clusterSelector) {
+        ServiceInfo result = serviceInfoHolder.getFailoverServiceInfo(serviceName, groupName, StringUtils.EMPTY);
+        return doSelectInstance(result, clusterSelector);
+    }
+
+    private ServiceInfo getServiceInfoBySubscribe(String serviceName, String groupName, List<String> clusters,
+            NamingSelector selector, boolean subscribe) throws NacosException {
         ServiceInfo serviceInfo;
         if (subscribe) {
-            serviceInfo = serviceInfoHolder.getServiceInfo(serviceName, groupName, clusterString);
-            if (null == serviceInfo || !clientProxy.isSubscribed(serviceName, groupName, clusterString)) {
-                serviceInfo = clientProxy.subscribe(serviceName, groupName, clusterString);
-            }
+            serviceInfo = serviceInfoHolder.getServiceInfo(serviceName, groupName, StringUtils.EMPTY);
+            serviceInfo = tryToSubscribe(serviceName, groupName, serviceInfo);
+            serviceInfo = doSelectInstance(serviceInfo, selector);
         } else {
+            String clusterString = NamingSelectorFactory.getUniqueClusterString(clusters);
             serviceInfo = clientProxy.queryInstancesOfService(serviceName, groupName, clusterString, false);
         }
         return serviceInfo;
     }
 
-    private ServiceInfo getServiceInfo(String serviceName, String groupName, List<String> clusters, boolean subscribe)
-            throws NacosException {
-        ServiceInfo serviceInfo;
-        String clusterString = StringUtils.join(clusters, ",");
-        if (serviceInfoHolder.isFailoverSwitch()) {
-            serviceInfo = getServiceInfoByFailover(serviceName, groupName, clusterString);
-            if (serviceInfo != null && serviceInfo.getHosts().size() > 0) {
-                NAMING_LOGGER.debug("getServiceInfo from failover,serviceName: {}  data:{}", serviceName,
-                        JacksonUtils.toJson(serviceInfo.getHosts()));
-                return serviceInfo;
-            }
+    private ServiceInfo tryToSubscribe(String serviceName, String groupName, ServiceInfo cachedServiceInfo) throws NacosException {
+        // not found in cache, service never subscribed.
+        if (null == cachedServiceInfo) {
+            return clientProxy.subscribe(serviceName, groupName, StringUtils.EMPTY);
         }
-
-        serviceInfo = getServiceInfoBySubscribe(serviceName, groupName, clusterString, subscribe);
+        // found in cache, and subscribed.
+        if (clientProxy.isSubscribed(serviceName, groupName, StringUtils.EMPTY)) {
+            return cachedServiceInfo;
+        }
+        // found in cached, but not subscribed, such as cached from local file when starting.
+        ServiceInfo result = cachedServiceInfo;
+        try {
+            result = clientProxy.subscribe(serviceName, groupName, StringUtils.EMPTY);
+        } catch (NacosException e) {
+            NAMING_LOGGER.warn("Subscribe from Server failed, will use local cache. fail message: ", e);
+        }
+        return result;
+    }
+
+    private ServiceInfo doSelectInstance(ServiceInfo serviceInfo, NamingSelector clusterSelector) {
+        if (null == serviceInfo) {
+            return null;
+        }
+        NamingContext context = new ServiceInfoContext(serviceInfo);
+        NamingResult result = clusterSelector.select(context);
+        serviceInfo.setHosts(result.getResult());
         return serviceInfo;
     }
 

client/src/main/java/com/alibaba/nacos/client/naming/selector/ServiceInfoContext.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 1999-2023 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.alibaba.nacos.client.naming.selector;
+
+import com.alibaba.nacos.api.naming.pojo.Instance;
+import com.alibaba.nacos.api.naming.pojo.ServiceInfo;
+import com.alibaba.nacos.api.naming.selector.NamingContext;
+
+import java.util.List;
+
+/**
+ * Service info context.
+ *
+ * @author xiweng.yy
+ */
+public class ServiceInfoContext implements NamingContext {
+
+    private final ServiceInfo serviceInfo;
+
+    public ServiceInfoContext(ServiceInfo serviceInfo) {
+        this.serviceInfo = serviceInfo;
+    }
+
+    @Override
+    public String getServiceName() {
+        return serviceInfo.getName();
+    }
+
+    @Override
+    public String getGroupName() {
+        return serviceInfo.getGroupName();
+    }
+
+    @Override
+    public String getClusters() {
+        return serviceInfo.getClusters();
+    }
+
+    @Override
+    public List<Instance> getInstances() {
+        return serviceInfo.getHosts();
+    }
+}