Start to use IdleStateHandler in Netty4

dubbo-common/src/main/java/org/apache/dubbo/common/utils/UrlUtils.java

@@ -467,6 +467,19 @@ public static boolean isProvider(URL url) {
                 PROVIDERS_CATEGORY.equals(url.getParameter(CATEGORY_KEY, PROVIDERS_CATEGORY));
     }
 
+    public static int getHeartbeat(URL url) {
+        return url.getParameter(Constants.HEARTBEAT_KEY, Constants.DEFAULT_HEARTBEAT);
+    }
+
+    public static int getIdleTimeout(URL url) {
+        int heartBeat = getHeartbeat(url);
+        int idleTimeout = url.getParameter(Constants.HEARTBEAT_TIMEOUT_KEY, heartBeat * 3);
+        if (idleTimeout < heartBeat * 2) {
+            throw new IllegalStateException("idleTimeout < heartbeatInterval * 2");
+        }
+        return idleTimeout;
+    }
+
     /**
      * Check if the given value matches the given pattern. The pattern supports wildcard "*".
      *

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/Client.java

@@ -25,7 +25,7 @@
  *
  * @see org.apache.dubbo.remoting.Transporter#connect(org.apache.dubbo.common.URL, ChannelHandler)
  */
-public interface Client extends Endpoint, Channel, Resetable {
+public interface Client extends Endpoint, Channel, Resetable, IdleSensible {
 
     /**
      * reconnect.
@@ -35,4 +35,4 @@ public interface Client extends Endpoint, Channel, Resetable {
     @Deprecated
     void reset(org.apache.dubbo.common.Parameters parameters);
 
-}
+}

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/IdleSensible.java

@@ -0,0 +1,37 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.dubbo.remoting;
+
+/**
+ * Indicate whether the implementation (for both server and client) has the ability to sense and handle idle connection.
+ * If the server has the ability to handle idle connection, it should close the connection when it happens, and if
+ * the client has the ability to handle idle connection, it should send the heartbeat to the server.
+ */
+public interface IdleSensible {
+    /**
+     * Whether the implementation can sense and handle the idle connection. By default it's false, the implementation
+     * relies on dedicated timer to take care of idle connection.
+     *
+     * @return whether has the ability to handle idle connection
+     */
+    default boolean canHandleIdle() {
+        return false;
+    }
+}

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/Server.java

@@ -28,7 +28,7 @@
  *
  * @see org.apache.dubbo.remoting.Transporter#bind(org.apache.dubbo.common.URL, ChannelHandler)
  */
-public interface Server extends Endpoint, Resetable {
+public interface Server extends Endpoint, Resetable, IdleSensible {
 
     /**
      * is bound.
@@ -55,4 +55,4 @@ public interface Server extends Endpoint, Resetable {
     @Deprecated
     void reset(org.apache.dubbo.common.Parameters parameters);
 
-}
+}

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/HeaderExchangeClient.java

@@ -33,38 +33,31 @@
 import java.util.Collections;
 import java.util.concurrent.TimeUnit;
 
+import static org.apache.dubbo.common.utils.UrlUtils.getHeartbeat;
+import static org.apache.dubbo.common.utils.UrlUtils.getIdleTimeout;
+
 /**
  * DefaultMessageClient
  */
 public class HeaderExchangeClient implements ExchangeClient {
 
     private final Client client;
     private final ExchangeChannel channel;
-    private int heartbeat;
-    private int idleTimeout;
-
-    private static final HashedWheelTimer IDLE_CHECK_TIMER = new HashedWheelTimer(new NamedThreadFactory("dubbo-client-idleCheck", true), 1,
-            TimeUnit.SECONDS, Constants.TICKS_PER_WHEEL);
 
+    private static final HashedWheelTimer IDLE_CHECK_TIMER = new HashedWheelTimer(
+            new NamedThreadFactory("dubbo-client-idleCheck", true), 1, TimeUnit.SECONDS, Constants.TICKS_PER_WHEEL);
     private HeartbeatTimerTask heartBeatTimerTask;
-
     private ReconnectTimerTask reconnectTimerTask;
 
-    public HeaderExchangeClient(Client client, boolean needHeartbeat) {
+    public HeaderExchangeClient(Client client, boolean startTimer) {
         Assert.notNull(client, "Client can't be null");
         this.client = client;
         this.channel = new HeaderExchangeChannel(client);
-        String dubbo = client.getUrl().getParameter(Constants.DUBBO_VERSION_KEY);
-
-        this.heartbeat = client.getUrl().getParameter(Constants.HEARTBEAT_KEY, dubbo != null &&
-                dubbo.startsWith("1.0.") ? Constants.DEFAULT_HEARTBEAT : 0);
-        this.idleTimeout = client.getUrl().getParameter(Constants.HEARTBEAT_TIMEOUT_KEY, heartbeat * 3);
-        if (idleTimeout < heartbeat * 2) {
-            throw new IllegalStateException("idleTimeout < heartbeatInterval * 2");
-        }
 
-        if (needHeartbeat) {
-            startIdleCheckTask();
+        if (startTimer) {
+            URL url = client.getUrl();
+            startReconnectTask(url);
+            startHeartBeatTask(url);
         }
     }
 
@@ -145,6 +138,7 @@ public void startClose() {
     @Override
     public void reset(URL url) {
         client.reset(url);
+        // FIXME, should cancel and restart timer tasks if parameters in the new URL are different?
     }
 
     @Override
@@ -178,25 +172,34 @@ public boolean hasAttribute(String key) {
         return channel.hasAttribute(key);
     }
 
-    private void startIdleCheckTask() {
-        AbstractTimerTask.ChannelProvider cp = () -> Collections.singletonList(HeaderExchangeClient.this);
-
-        long heartbeatTick = calculateLeastDuration(heartbeat);
-        long heartbeatTimeoutTick = calculateLeastDuration(idleTimeout);
-        HeartbeatTimerTask heartBeatTimerTask = new HeartbeatTimerTask(cp, heartbeatTick, heartbeat);
-        ReconnectTimerTask reconnectTimerTask = new ReconnectTimerTask(cp, heartbeatTimeoutTick, idleTimeout);
-
-        this.heartBeatTimerTask = heartBeatTimerTask;
-        this.reconnectTimerTask = reconnectTimerTask;
+    private void startHeartBeatTask(URL url) {
+        if (!client.canHandleIdle()) {
+            AbstractTimerTask.ChannelProvider cp = () -> Collections.singletonList(HeaderExchangeClient.this);
+            int heartbeat = getHeartbeat(url);
+            long heartbeatTick = calculateLeastDuration(heartbeat);
+            this.heartBeatTimerTask = new HeartbeatTimerTask(cp, heartbeatTick, heartbeat);
+            IDLE_CHECK_TIMER.newTimeout(heartBeatTimerTask, heartbeatTick, TimeUnit.MILLISECONDS);
+        }
+    }
 
-        // init task and start timer.
-        IDLE_CHECK_TIMER.newTimeout(heartBeatTimerTask, heartbeatTick, TimeUnit.MILLISECONDS);
-        IDLE_CHECK_TIMER.newTimeout(reconnectTimerTask, heartbeatTimeoutTick, TimeUnit.MILLISECONDS);
+    private void startReconnectTask(URL url) {
+        if (shouldReconnect(url)) {
+            AbstractTimerTask.ChannelProvider cp = () -> Collections.singletonList(HeaderExchangeClient.this);
+            int idleTimeout = getIdleTimeout(url);
+            long heartbeatTimeoutTick = calculateLeastDuration(idleTimeout);
+            this.reconnectTimerTask = new ReconnectTimerTask(cp, heartbeatTimeoutTick, idleTimeout);
+            IDLE_CHECK_TIMER.newTimeout(reconnectTimerTask, heartbeatTimeoutTick, TimeUnit.MILLISECONDS);
+        }
     }
 
     private void doClose() {
-        heartBeatTimerTask.cancel();
-        reconnectTimerTask.cancel();
+        if (heartBeatTimerTask != null) {
+            heartBeatTimerTask.cancel();
+        }
+
+        if (reconnectTimerTask != null) {
+            reconnectTimerTask.cancel();
+        }
     }
 
     /**
@@ -210,6 +213,10 @@ private long calculateLeastDuration(int time) {
         }
     }
 
+    private boolean shouldReconnect(URL url) {
+        return url.getParameter(Constants.RECONNECT_KEY, true);
+    }
+
     @Override
     public String toString() {
         return "HeaderExchangeClient [channel=" + channel + "]";

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/HeaderExchangeServer.java

@@ -25,6 +25,7 @@
 import org.apache.dubbo.common.utils.Assert;
 import org.apache.dubbo.common.utils.CollectionUtils;
 import org.apache.dubbo.common.utils.NamedThreadFactory;
+import org.apache.dubbo.common.utils.UrlUtils;
 import org.apache.dubbo.remoting.Channel;
 import org.apache.dubbo.remoting.ChannelHandler;
 import org.apache.dubbo.remoting.RemotingException;
@@ -49,8 +50,6 @@ public class HeaderExchangeServer implements ExchangeServer {
     protected final Logger logger = LoggerFactory.getLogger(getClass());
 
     private final Server server;
-    private int heartbeat;
-    private int idleTimeout;
     private AtomicBoolean closed = new AtomicBoolean(false);
 
     private static final HashedWheelTimer IDLE_CHECK_TIMER = new HashedWheelTimer(new NamedThreadFactory("dubbo-server-idleCheck", true), 1,
@@ -61,13 +60,7 @@ public class HeaderExchangeServer implements ExchangeServer {
     public HeaderExchangeServer(Server server) {
         Assert.notNull(server, "server == null");
         this.server = server;
-        this.heartbeat = server.getUrl().getParameter(Constants.HEARTBEAT_KEY, 0);
-        this.idleTimeout = server.getUrl().getParameter(Constants.HEARTBEAT_TIMEOUT_KEY, heartbeat * 3);
-        if (idleTimeout < heartbeat * 2) {
-            throw new IllegalStateException("idleTimeout < heartbeatInterval * 2");
-        }
-
-        startIdleCheckTask();
+        startIdleCheckTask(getUrl());
     }
 
     public Server getServer() {
@@ -154,7 +147,9 @@ private void doClose() {
     }
 
     private void cancelCloseTask() {
-        closeTimerTask.cancel();
+        if (closeTimerTask != null) {
+            closeTimerTask.cancel();
+        }
     }
 
     @Override
@@ -210,21 +205,13 @@ public ChannelHandler getChannelHandler() {
     public void reset(URL url) {
         server.reset(url);
         try {
-            if (url.hasParameter(Constants.HEARTBEAT_KEY)
-                    || url.hasParameter(Constants.HEARTBEAT_TIMEOUT_KEY)) {
-                int h = url.getParameter(Constants.HEARTBEAT_KEY, heartbeat);
-                int t = url.getParameter(Constants.HEARTBEAT_TIMEOUT_KEY, h * 3);
-                if (t < h * 2) {
-                    throw new IllegalStateException("idleTimeout < heartbeatInterval * 2");
-                }
-                if (h != heartbeat || t != idleTimeout) {
-                    heartbeat = h;
-                    idleTimeout = t;
-
-                    // we need cancel the exist closeTimeout first.
-                    cancelCloseTask();
-                    startIdleCheckTask();
-                }
+            int currHeartbeat = UrlUtils.getHeartbeat(getUrl());
+            int currIdleTimeout = UrlUtils.getIdleTimeout(getUrl());
+            int heartbeat = UrlUtils.getHeartbeat(url);
+            int idleTimeout = UrlUtils.getIdleTimeout(url);
+            if (currHeartbeat != heartbeat || currIdleTimeout != idleTimeout) {
+                cancelCloseTask();
+                startIdleCheckTask(url);
             }
         } catch (Throwable t) {
             logger.error(t.getMessage(), t);
@@ -266,15 +253,16 @@ private long calculateLeastDuration(int time) {
         }
     }
 
-    private void startIdleCheckTask() {
-        AbstractTimerTask.ChannelProvider cp = () -> unmodifiableCollection(HeaderExchangeServer.this.getChannels());
-
-        long idleTimeoutTick = calculateLeastDuration(idleTimeout);
-        CloseTimerTask closeTimerTask = new CloseTimerTask(cp, idleTimeoutTick, idleTimeout);
-        this.closeTimerTask = closeTimerTask;
+    private void startIdleCheckTask(URL url) {
+        if (!server.canHandleIdle()) {
+            AbstractTimerTask.ChannelProvider cp = () -> unmodifiableCollection(HeaderExchangeServer.this.getChannels());
+            int idleTimeout = UrlUtils.getIdleTimeout(url);
+            long idleTimeoutTick = calculateLeastDuration(idleTimeout);
+            CloseTimerTask closeTimerTask = new CloseTimerTask(cp, idleTimeoutTick, idleTimeout);
+            this.closeTimerTask = closeTimerTask;
 
-        // init task and start timer.
-        IDLE_CHECK_TIMER.newTimeout(closeTimerTask, idleTimeoutTick, TimeUnit.MILLISECONDS);
+            // init task and start timer.
+            IDLE_CHECK_TIMER.newTimeout(closeTimerTask, idleTimeoutTick, TimeUnit.MILLISECONDS);
+        }
     }
-
 }

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/ReconnectTimerTask.java

@@ -41,9 +41,18 @@ protected void doTask(Channel channel) {
         try {
             Long lastRead = lastRead(channel);
             Long now = now();
+
+            // Rely on reconnect timer to reconnect when AbstractClient.doConnect fails to init the connection
+            if (!channel.isConnected()) {
+                try {
+                    logger.info("Initial connection to " + channel);
+                    ((Client) channel).reconnect();
+                } catch (Exception e) {
+                    logger.error("Fail to connect to " + channel, e);
+                }
             // check pong at client
-            if (lastRead != null && now - lastRead > idleTimeout) {
-                logger.warn("Close channel " + channel + ", because heartbeat read idle time out: "
+            } else if (lastRead != null && now - lastRead > idleTimeout) {
+                logger.warn("Reconnect to channel " + channel + ", because heartbeat read idle time out: "
                         + idleTimeout + "ms");
                 try {
                     ((Client) channel).reconnect();