Java tutorial
/* * 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.transport.netty4; import org.apache.dubbo.common.URL; import org.apache.dubbo.common.Version; import org.apache.dubbo.common.logger.Logger; import org.apache.dubbo.common.logger.LoggerFactory; import org.apache.dubbo.common.utils.ConfigUtils; import org.apache.dubbo.common.utils.NetUtils; import org.apache.dubbo.remoting.ChannelHandler; import org.apache.dubbo.remoting.Constants; import org.apache.dubbo.remoting.RemotingException; import org.apache.dubbo.remoting.transport.AbstractClient; import org.apache.dubbo.remoting.utils.UrlUtils; import io.netty.bootstrap.Bootstrap; import io.netty.buffer.PooledByteBufAllocator; import io.netty.channel.Channel; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelOption; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.nio.NioSocketChannel; import io.netty.handler.proxy.Socks5ProxyHandler; import io.netty.handler.timeout.IdleStateHandler; import io.netty.util.concurrent.DefaultThreadFactory; import static java.util.concurrent.TimeUnit.MILLISECONDS; import java.net.InetSocketAddress; /** * NettyClient. */ public class NettyClient extends AbstractClient { private static final Logger logger = LoggerFactory.getLogger(NettyClient.class); /** * netty client bootstrap */ private static final NioEventLoopGroup nioEventLoopGroup = new NioEventLoopGroup(Constants.DEFAULT_IO_THREADS, new DefaultThreadFactory("NettyClientWorker", true)); private static final String SOCKS_PROXY_HOST = "socksProxyHost"; private static final String SOCKS_PROXY_PORT = "socksProxyPort"; private static final String DEFAULT_SOCKS_PROXY_PORT = "1080"; private Bootstrap bootstrap; /** * current channel. Each successful invocation of {@link NettyClient#doConnect()} will * replace this with new channel and close old channel. * <b>volatile, please copy reference to use.</b> */ private volatile Channel channel; /** * The constructor of NettyClient. * It wil init and start netty. */ public NettyClient(final URL url, final ChannelHandler handler) throws RemotingException { // you can customize name and type of client thread pool by THREAD_NAME_KEY and THREADPOOL_KEY in CommonConstants. // the handler will be warped: MultiMessageHandler->HeartbeatHandler->handler super(url, wrapChannelHandler(url, handler)); } /** * Init bootstrap * * @throws Throwable */ @Override protected void doOpen() throws Throwable { final NettyClientHandler nettyClientHandler = new NettyClientHandler(getUrl(), this); bootstrap = new Bootstrap(); bootstrap.group(nioEventLoopGroup).option(ChannelOption.SO_KEEPALIVE, true) .option(ChannelOption.TCP_NODELAY, true) .option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT) //.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, getTimeout()) .channel(NioSocketChannel.class); if (getConnectTimeout() < 3000) { bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 3000); } else { bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, getConnectTimeout()); } bootstrap.handler(new ChannelInitializer() { @Override protected void initChannel(Channel ch) throws Exception { int heartbeatInterval = UrlUtils.getHeartbeat(getUrl()); NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec(), getUrl(), NettyClient.this); ch.pipeline()//.addLast("logging",new LoggingHandler(LogLevel.INFO))//for debug .addLast("decoder", adapter.getDecoder()).addLast("encoder", adapter.getEncoder()) .addLast("client-idle-handler", new IdleStateHandler(heartbeatInterval, 0, 0, MILLISECONDS)) .addLast("handler", nettyClientHandler); String socksProxyHost = ConfigUtils.getProperty(SOCKS_PROXY_HOST); if (socksProxyHost != null) { int socksProxyPort = Integer .parseInt(ConfigUtils.getProperty(SOCKS_PROXY_PORT, DEFAULT_SOCKS_PROXY_PORT)); Socks5ProxyHandler socks5ProxyHandler = new Socks5ProxyHandler( new InetSocketAddress(socksProxyHost, socksProxyPort)); ch.pipeline().addFirst(socks5ProxyHandler); } } }); } @Override protected void doConnect() throws Throwable { long start = System.currentTimeMillis(); ChannelFuture future = bootstrap.connect(getConnectAddress()); try { boolean ret = future.awaitUninterruptibly(getConnectTimeout(), MILLISECONDS); if (ret && future.isSuccess()) { Channel newChannel = future.channel(); try { // Close old channel // copy reference Channel oldChannel = NettyClient.this.channel; if (oldChannel != null) { try { if (logger.isInfoEnabled()) { logger.info("Close old netty channel " + oldChannel + " on create new netty channel " + newChannel); } oldChannel.close(); } finally { NettyChannel.removeChannelIfDisconnected(oldChannel); } } } finally { if (NettyClient.this.isClosed()) { try { if (logger.isInfoEnabled()) { logger.info( "Close new netty channel " + newChannel + ", because the client closed."); } newChannel.close(); } finally { NettyClient.this.channel = null; NettyChannel.removeChannelIfDisconnected(newChannel); } } else { NettyClient.this.channel = newChannel; } } } else if (future.cause() != null) { throw new RemotingException(this, "client(url: " + getUrl() + ") failed to connect to server " + getRemoteAddress() + ", error message is:" + future.cause().getMessage(), future.cause()); } else { throw new RemotingException(this, "client(url: " + getUrl() + ") failed to connect to server " + getRemoteAddress() + " client-side timeout " + getConnectTimeout() + "ms (elapsed: " + (System.currentTimeMillis() - start) + "ms) from netty client " + NetUtils.getLocalHost() + " using dubbo version " + Version.getVersion()); } } finally { // just add new valid channel to NettyChannel's cache if (!isConnected()) { //future.cancel(true); } } } @Override protected void doDisConnect() throws Throwable { try { NettyChannel.removeChannelIfDisconnected(channel); } catch (Throwable t) { logger.warn(t.getMessage()); } } @Override protected void doClose() throws Throwable { // can't shutdown nioEventLoopGroup because the method will be invoked when closing one channel but not a client, // but when and how to close the nioEventLoopGroup ? // nioEventLoopGroup.shutdownGracefully(); } @Override protected org.apache.dubbo.remoting.Channel getChannel() { Channel c = channel; if (c == null || !c.isActive()) { return null; } return NettyChannel.getOrAddChannel(c, getUrl(), this); } @Override public boolean canHandleIdle() { return true; } }