[ISSUE #11253]To fix the triggering of the listener upon failover con… (#11254)

* [ISSUE #11253]To fix the triggering of the listener upon failover content changes.

* [ISSUE #11255]Update style.

* [ISSUE #11255]Fix UdpConnectorTest#testContainAck.

client/src/main/java/com/alibaba/nacos/client/config/impl/CacheData.java

@@ -93,7 +93,7 @@ public class CacheData {
         LOGGER.info("nacos.cache.data.init.snapshot = {} ", initSnapshot);
     }
     
-    private final String envName;
+    public final String envName;
     
     private final ConfigFilterChainManager configFilterChainManager;
     
@@ -124,13 +124,13 @@ public class CacheData {
     /**
      * local cache change timestamp.
      */
-    private volatile AtomicLong lastModifiedTs = new AtomicLong(0);
+    private final AtomicLong lastModifiedTs = new AtomicLong(0);
     
     /**
      * notify change flag,for notify&sync concurrent control. 1.reset to false if starting to sync with server. 2.update
      * to true if receive config change notification.
      */
-    private volatile AtomicBoolean receiveNotifyChanged = new AtomicBoolean(false);
+    private final AtomicBoolean receiveNotifyChanged = new AtomicBoolean(false);
     
     private int taskId;
     
@@ -139,7 +139,7 @@ public class CacheData {
     /**
      * if is cache data md5 sync with the server.
      */
-    private volatile AtomicBoolean isConsistentWithServer = new AtomicBoolean();
+    private final AtomicBoolean isConsistentWithServer = new AtomicBoolean();
     
     /**
      * if is cache data is discard,need to remove.

client/src/main/java/com/alibaba/nacos/client/config/impl/ClientWorker.java

@@ -36,8 +36,6 @@ import com.alibaba.nacos.api.exception.NacosException;
 import com.alibaba.nacos.api.remote.RemoteConstants;
 import com.alibaba.nacos.api.remote.request.Request;
 import com.alibaba.nacos.api.remote.response.Response;
-import com.alibaba.nacos.common.remote.client.Connection;
-import com.alibaba.nacos.plugin.auth.api.RequestResource;
 import com.alibaba.nacos.client.config.common.GroupKey;
 import com.alibaba.nacos.client.config.filter.impl.ConfigFilterChainManager;
 import com.alibaba.nacos.client.config.filter.impl.ConfigResponse;
@@ -55,6 +53,7 @@ import com.alibaba.nacos.common.notify.Event;
 import com.alibaba.nacos.common.notify.NotifyCenter;
 import com.alibaba.nacos.common.notify.listener.Subscriber;
 import com.alibaba.nacos.common.remote.ConnectionType;
+import com.alibaba.nacos.common.remote.client.Connection;
 import com.alibaba.nacos.common.remote.client.ConnectionEventListener;
 import com.alibaba.nacos.common.remote.client.RpcClient;
 import com.alibaba.nacos.common.remote.client.RpcClientFactory;
@@ -66,10 +65,12 @@ import com.alibaba.nacos.common.utils.MD5Utils;
 import com.alibaba.nacos.common.utils.StringUtils;
 import com.alibaba.nacos.common.utils.ThreadUtils;
 import com.alibaba.nacos.common.utils.VersionUtils;
+import com.alibaba.nacos.plugin.auth.api.RequestResource;
 import com.google.gson.Gson;
 import com.google.gson.JsonObject;
 import org.slf4j.Logger;
 
+import java.io.File;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -123,11 +124,11 @@ public class ClientWorker implements Closeable {
     
     private final ConfigFilterChainManager configFilterChainManager;
     
-    private String uuid = UUID.randomUUID().toString();
+    private final String uuid = UUID.randomUUID().toString();
     
     private long timeout;
     
-    private ConfigRpcTransportClient agent;
+    private final ConfigRpcTransportClient agent;
     
     private int taskPenaltyTime;
     
@@ -570,7 +571,7 @@ public class ClientWorker implements Closeable {
     
         private final BlockingQueue<Object> listenExecutebell = new ArrayBlockingQueue<>(1);
     
-        private Object bellItem = new Object();
+        private final Object bellItem = new Object();
         
         private long lastAllSyncTime = System.currentTimeMillis();
         
@@ -780,6 +781,8 @@ public class ClientWorker implements Closeable {
                 
                 synchronized (cache) {
     
+                    checkLocalConfig(cache);
+    
                     // check local listeners consistent.
                     if (cache.isConsistentWithServer()) {
                         cache.checkListenerMd5();
@@ -788,28 +791,19 @@ public class ClientWorker implements Closeable {
                         }
                     }
     
+                    // If local configuration information is used, then skip the processing directly.
+                    if (cache.isUseLocalConfigInfo()) {
+                        continue;
+                    }
+    
                     if (!cache.isDiscard()) {
-                        //get listen  config
+                        List<CacheData> cacheDatas = listenCachesMap.computeIfAbsent(String.valueOf(cache.getTaskId()),
-                        if (!cache.isUseLocalConfigInfo()) {
+                                k -> new LinkedList<>());
-                            List<CacheData> cacheDatas = listenCachesMap.get(String.valueOf(cache.getTaskId()));
-                            if (cacheDatas == null) {
-                                cacheDatas = new LinkedList<>();
-                                listenCachesMap.put(String.valueOf(cache.getTaskId()), cacheDatas);
-                            }
                         cacheDatas.add(cache);
-                            
+                    } else {
-                        }
+                        List<CacheData> cacheDatas = removeListenCachesMap.computeIfAbsent(
-                    } else if (cache.isDiscard() && CollectionUtils.isEmpty(cache.getListeners())) {
+                                String.valueOf(cache.getTaskId()), k -> new LinkedList<>());
-                        
-                        if (!cache.isUseLocalConfigInfo()) {
-                            List<CacheData> cacheDatas = removeListenCachesMap.get(String.valueOf(cache.getTaskId()));
-                            if (cacheDatas == null) {
-                                cacheDatas = new LinkedList<>();
-                                removeListenCachesMap.put(String.valueOf(cache.getTaskId()), cacheDatas);
-                            }
                         cacheDatas.add(cache);
-                            
-                        }
                     }
                 }
                 
@@ -831,6 +825,56 @@ public class ClientWorker implements Closeable {
     
         }
     
+        /**
+         * Checks and handles local configuration for a given CacheData object. This method evaluates the use of
+         * failover files for local configuration storage and updates the CacheData accordingly.
+         *
+         * @param cacheData The CacheData object to be processed.
+         */
+        public void checkLocalConfig(CacheData cacheData) {
+            final String dataId = cacheData.dataId;
+            final String group = cacheData.group;
+            final String tenant = cacheData.tenant;
+            final String envName = cacheData.envName;
+    
+            // Check if a failover file exists for the specified dataId, group, and tenant.
+            File file = LocalConfigInfoProcessor.getFailoverFile(envName, dataId, group, tenant);
+    
+            // If not using local config info and a failover file exists, load and use it.
+            if (!cacheData.isUseLocalConfigInfo() && file.exists()) {
+                String content = LocalConfigInfoProcessor.getFailover(envName, dataId, group, tenant);
+                final String md5 = MD5Utils.md5Hex(content, Constants.ENCODE);
+                cacheData.setUseLocalConfigInfo(true);
+                cacheData.setLocalConfigInfoVersion(file.lastModified());
+                cacheData.setContent(content);
+                LOGGER.warn(
+                        "[{}] [failover-change] failover file created. dataId={}, group={}, tenant={}, md5={}, content={}",
+                        envName, dataId, group, tenant, md5, ContentUtils.truncateContent(content));
+                return;
+            }
+    
+            // If use local config info, but the failover file is deleted, switch back to server config.
+            if (cacheData.isUseLocalConfigInfo() && !file.exists()) {
+                cacheData.setUseLocalConfigInfo(false);
+                LOGGER.warn("[{}] [failover-change] failover file deleted. dataId={}, group={}, tenant={}", envName,
+                        dataId, group, tenant);
+                return;
+            }
+    
+            // When the failover file content changes, indicating a change in local configuration.
+            if (cacheData.isUseLocalConfigInfo() && file.exists()
+                    && cacheData.getLocalConfigInfoVersion() != file.lastModified()) {
+                String content = LocalConfigInfoProcessor.getFailover(envName, dataId, group, tenant);
+                final String md5 = MD5Utils.md5Hex(content, Constants.ENCODE);
+                cacheData.setUseLocalConfigInfo(true);
+                cacheData.setLocalConfigInfoVersion(file.lastModified());
+                cacheData.setContent(content);
+                LOGGER.warn(
+                        "[{}] [failover-change] failover file changed. dataId={}, group={}, tenant={}, md5={}, content={}",
+                        envName, dataId, group, tenant, md5, ContentUtils.truncateContent(content));
+            }
+        }
+    
         private ExecutorService ensureSyncExecutor(String taskId) {
             if (!multiTaskExecutor.containsKey(taskId)) {
                 multiTaskExecutor.put(taskId,
@@ -1180,7 +1224,7 @@ public class ClientWorker implements Closeable {
             try {
                 return getOneRunningClient().isRunning();
             } catch (NacosException e) {
-                LOGGER.warn("check server status failed. error={}", e);
+                LOGGER.warn("check server status failed.", e);
                 return false;
             }
         }

naming/src/test/java/com/alibaba/nacos/naming/remote/udp/UdpConnectorTest.java

@@ -91,7 +91,7 @@ public class UdpConnectorTest {
     
     @Test
     public void testContainAck() {
-        when(ackMap.containsKey(Mockito.anyString())).thenReturn(true);
+        when(ackMap.containsKey("1111")).thenReturn(true);
         Assert.assertTrue(udpConnector.containAck("1111"));
     }