[FIX_#3789][remote]cherry pick from dev to support netty heart beat

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/config/NettyClientConfig.java

@@ -48,6 +48,11 @@ public class NettyClientConfig {
      */
     private int receiveBufferSize = 65535;
 
+    /**
+     * connect timeout millis
+     */
+    private int connectTimeoutMillis = 3000;
+
     public int getWorkerThreads() {
         return workerThreads;
     }
@@ -88,4 +93,11 @@ public class NettyClientConfig {
         this.receiveBufferSize = receiveBufferSize;
     }
 
+    public int getConnectTimeoutMillis() {
+        return connectTimeoutMillis;
+    }
+
+    public void setConnectTimeoutMillis(int connectTimeoutMillis) {
+        this.connectTimeoutMillis = connectTimeoutMillis;
+    }
 }

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/utils/Constants.java

@@ -45,4 +45,14 @@ public class Constants {
 
     public static final String LOCAL_ADDRESS = IPUtils.getFirstNoLoopbackIP4Address();
 
+    /**
+     * netty epoll enable switch
+     */
+    public static final String NETTY_EPOLL_ENABLE = System.getProperty("netty.epoll.enable", "true");
+
+    /**
+     * OS Name
+     */
+    public static final String OS_NAME = System.getProperty("os.name");
+
 }

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/utils/NettyUtils.java

@@ -1,7 +1,62 @@
+/*
+ * 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.dolphinscheduler.remote.utils;
 
+import io.netty.channel.epoll.Epoll;
+import io.netty.channel.epoll.EpollServerSocketChannel;
+import io.netty.channel.epoll.EpollSocketChannel;
+import io.netty.channel.socket.ServerSocketChannel;
+import io.netty.channel.socket.SocketChannel;
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+import io.netty.channel.socket.nio.NioSocketChannel;
+
 /**
- * Created by Administrator on 2020/10/14.
+ * NettyUtils
  */
 public class NettyUtils {
-}
+
+    private NettyUtils() {
+    }
+
+    public static boolean useEpoll() {
+        String osName = Constants.OS_NAME;
+        if (!osName.toLowerCase().contains("linux")) {
+            return false;
+        }
+        if (!Epoll.isAvailable()) {
+            return false;
+        }
+        String enableNettyEpoll = Constants.NETTY_EPOLL_ENABLE;
+        return Boolean.parseBoolean(enableNettyEpoll);
+    }
+
+    public static Class<? extends ServerSocketChannel> getServerSocketChannelClass() {
+        if (useEpoll()) {
+            return EpollServerSocketChannel.class;
+        }
+        return NioServerSocketChannel.class;
+    }
+
+    public static Class<? extends SocketChannel> getSocketChannelClass() {
+        if (useEpoll()) {
+            return EpollSocketChannel.class;
+        }
+        return NioSocketChannel.class;
+    }
+
+}