Fix unregister when client destroyed（referenceconfig#destroy）

dubbo-registry/dubbo-registry-api/src/main/java/org/apache/dubbo/registry/integration/RegistryDirectory.java

@@ -23,10 +23,10 @@
 import org.apache.dubbo.common.logger.Logger;
 import org.apache.dubbo.common.logger.LoggerFactory;
 import org.apache.dubbo.common.utils.Assert;
+import org.apache.dubbo.common.utils.CollectionUtils;
 import org.apache.dubbo.common.utils.NetUtils;
 import org.apache.dubbo.common.utils.StringUtils;
 import org.apache.dubbo.common.utils.UrlUtils;
-import org.apache.dubbo.common.utils.CollectionUtils;
 import org.apache.dubbo.configcenter.DynamicConfiguration;
 import org.apache.dubbo.registry.NotifyListener;
 import org.apache.dubbo.registry.Registry;
@@ -90,6 +90,8 @@ public class RegistryDirectory<T> extends AbstractDirectory<T> implements Notify
 
     private volatile URL overrideDirectoryUrl; // Initialization at construction time, assertion not null, and always assign non null value
 
+    private volatile URL registeredConsumerUrl;
+
     /**
      * override rules
      * Priority: override>-D>consumer>provider
@@ -158,6 +160,15 @@ public void destroy() {
         if (isDestroyed()) {
             return;
         }
+
+        // unregister.
+        try {
+            if (getRegisteredConsumerUrl() != null && registry != null && registry.isAvailable()) {
+                registry.unregister(getRegisteredConsumerUrl());
+            }
+        } catch (Throwable t) {
+            logger.warn("unexpected error when unregister service " + serviceKey + "from registry" + registry.getUrl(), t);
+        }
         // unsubscribe.
         try {
             if (getConsumerUrl() != null && registry != null && registry.isAvailable()) {
@@ -565,6 +576,14 @@ public URL getUrl() {
         return this.overrideDirectoryUrl;
     }
 
+    public URL getRegisteredConsumerUrl() {
+        return registeredConsumerUrl;
+    }
+
+    public void setRegisteredConsumerUrl(URL registeredConsumerUrl) {
+        this.registeredConsumerUrl = registeredConsumerUrl;
+    }
+
     @Override
     public boolean isAvailable() {
         if (isDestroyed()) {

dubbo-registry/dubbo-registry-api/src/main/java/org/apache/dubbo/registry/integration/RegistryProtocol.java

@@ -372,7 +372,8 @@ private <T> Invoker<T> doRefer(Cluster cluster, Registry registry, Class<T> type
         Map<String, String> parameters = new HashMap<String, String>(directory.getUrl().getParameters());
         URL subscribeUrl = new URL(CONSUMER_PROTOCOL, parameters.remove(REGISTER_IP_KEY), 0, type.getName(), parameters);
         if (!ANY_VALUE.equals(url.getServiceInterface()) && url.getParameter(REGISTER_KEY, true)) {
-            registry.register(getRegisteredConsumerUrl(subscribeUrl, url));
+            directory.setRegisteredConsumerUrl(getRegisteredConsumerUrl(subscribeUrl, url));
+            registry.register(directory.getRegisteredConsumerUrl());
         }
         directory.buildRouterChain(subscribeUrl);
         directory.subscribe(subscribeUrl.addParameter(CATEGORY_KEY,
@@ -383,7 +384,7 @@ private <T> Invoker<T> doRefer(Cluster cluster, Registry registry, Class<T> type
         return invoker;
     }
 
-    private URL getRegisteredConsumerUrl(final URL consumerUrl, URL registryUrl) {
+    public URL getRegisteredConsumerUrl(final URL consumerUrl, URL registryUrl) {
         if (!registryUrl.getParameter(SIMPLIFIED_KEY, false)) {
             return consumerUrl.addParameters(CATEGORY_KEY, CONSUMERS_CATEGORY,
                     CHECK_KEY, String.valueOf(false));

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/transport/AbstractClient.java

@@ -153,6 +153,8 @@ private synchronized void initConnectStatusCheckCommand() {
                 @Override
                 public void run() {
                     try {
+                        if (cancelFutureIfOffline()) return;
+
                         if (!isConnected()) {
                             connect();
                         } else {
@@ -173,7 +175,29 @@ public void run() {
                         }
                     }
                 }
+
+                private boolean cancelFutureIfOffline() {
+                    /**
+                     * If the provider service is detected offline,
+                     * the client should not attempt to connect again.
+                     *
+                     * issue: https://github.com/apache/incubator-dubbo/issues/3158
+                     */
+                    if(isClosed()) {
+                        ScheduledFuture<?> future = reconnectExecutorFuture;
+                        if(future != null && !future.isCancelled()){
+                            /**
+                             *  Client has been destroyed and
+                             *  scheduled task should be cancelled.
+                             */
+                            future.cancel(true);
+                        }
+                        return true;
+                    }
+                    return false;
+                }
             };
+
             reconnectExecutorFuture = reconnectExecutorService.scheduleWithFixedDelay(connectStatusCheckCommand, reconnect, reconnect, TimeUnit.MILLISECONDS);
         }
     }
@@ -345,14 +369,14 @@ public void reconnect() throws RemotingException {
     @Override
     public void close() {
         try {
-            if (executor != null) {
-                ExecutorUtil.shutdownNow(executor, 100);
-            }
+            super.close();
         } catch (Throwable e) {
             logger.warn(e.getMessage(), e);
         }
         try {
-            super.close();
+            if (executor != null) {
+                ExecutorUtil.shutdownNow(executor, 100);
+            }
         } catch (Throwable e) {
             logger.warn(e.getMessage(), e);
         }