Dubbo源码分析之提供端（3）

版权声明： https://blog.csdn.net/ph3636/article/details/91374579

包装交换处理类，增加解码以及处理请求的功能

public HeaderExchangeHandler(ExchangeHandler handler) {
    if (handler == null) {
        throw new IllegalArgumentException("handler == null");
    }
    this.handler = handler;
}

public DecodeHandler(ChannelHandler handler) {
    super(handler);
}

protected AbstractChannelHandlerDelegate(ChannelHandler handler) {
    Assert.notNull(handler, "handler == null");
    this.handler = handler;
}

获取传输层类并把这些处理类绑定上后返回交换服务器。

public ExchangeServer bind(URL url, ExchangeHandler handler) throws RemotingException {
    return new HeaderExchangeServer(Transporters.bind(url, new DecodeHandler(new HeaderExchangeHandler(handler))));
}

传输层默认为netty，当然也可以通过设置URL参数来自定义

public static Server bind(URL url, ChannelHandler... handlers) throws RemotingException {
    if (url == null) {
        throw new IllegalArgumentException("url == null");
    }
    if (handlers == null || handlers.length == 0) {
        throw new IllegalArgumentException("handlers == null");
    }
    ChannelHandler handler;
    if (handlers.length == 1) {
        handler = handlers[0];
    } else {
        handler = new ChannelHandlerDispatcher(handlers);
    }
    return getTransporter().bind(url, handler);
}

public static Transporter getTransporter() {
    return ExtensionLoader.getExtensionLoader(Transporter.class).getAdaptiveExtension();
}

绑定后直接返回netty服务端

public Server bind(URL url, ChannelHandler listener) throws RemotingException {
    return new NettyServer(url, listener);
}

public NettyServer(URL url, ChannelHandler handler) throws RemotingException {
    super(url, ChannelHandlers.wrap(handler, ExecutorUtil.setThreadName(url, SERVER_THREAD_POOL_NAME)));
}

给URL添加自定义的线程名字参数

public static URL setThreadName(URL url, String defaultName) {
    String name = url.getParameter(Constants.THREAD_NAME_KEY, defaultName);
    name = name + "-" + url.getAddress();
    url = url.addParameter(Constants.THREAD_NAME_KEY, name);
    return url;
}

包装通道处理器

public static ChannelHandler wrap(ChannelHandler handler, URL url) {
    return ChannelHandlers.getInstance().wrapInternal(handler, url);
}
    
protected ChannelHandler wrapInternal(ChannelHandler handler, URL url) {
    return new MultiMessageHandler(new HeartbeatHandler(ExtensionLoader.getExtensionLoader(Dispatcher.class)
            .getAdaptiveExtension().dispatch(handler, url)));
}

默认调度器为AllDispatcher

public ChannelHandler dispatch(ChannelHandler handler, URL url) {
    return new AllChannelHandler(handler, url);
}

public AllChannelHandler(ChannelHandler handler, URL url) {
    super(handler, url);
}

public WrappedChannelHandler(ChannelHandler handler, URL url) {
    this.handler = handler;
    this.url = url;
    executor = (ExecutorService) ExtensionLoader.getExtensionLoader(ThreadPool.class).getAdaptiveExtension().getExecutor(url);

    String componentKey = Constants.EXECUTOR_SERVICE_COMPONENT_KEY;
    if (Constants.CONSUMER_SIDE.equalsIgnoreCase(url.getParameter(Constants.SIDE_KEY))) {
        componentKey = Constants.CONSUMER_SIDE;
    }
    DataStore dataStore = ExtensionLoader.getExtensionLoader(DataStore.class).getDefaultExtension();
    dataStore.put(componentKey, Integer.toString(url.getPort()), executor);
}

获取对应的线程池

public class FixedThreadPool implements ThreadPool {

    @Override
    public Executor getExecutor(URL url) {
        String name = url.getParameter(Constants.THREAD_NAME_KEY, Constants.DEFAULT_THREAD_NAME);
        int threads = url.getParameter(Constants.THREADS_KEY, Constants.DEFAULT_THREADS);
        int queues = url.getParameter(Constants.QUEUES_KEY, Constants.DEFAULT_QUEUES);
        return new ThreadPoolExecutor(threads, threads, 0, TimeUnit.MILLISECONDS,
                queues == 0 ? new SynchronousQueue<Runnable>() :
                        (queues < 0 ? new LinkedBlockingQueue<Runnable>()
                                : new LinkedBlockingQueue<Runnable>(queues)),
                new NamedInternalThreadFactory(name, true), new AbortPolicyWithReport(name, url));
    }
}

默认数据存储器为SimpleDataStore，把线程池保存到指定的key，filed中。

public void put(String componentName, String key, Object value) {
    Map<String, Object> componentData = data.get(componentName);
    if (null == componentData) {
        data.putIfAbsent(componentName, new ConcurrentHashMap<String, Object>());
        componentData = data.get(componentName);
    }
    componentData.put(key, value);
}

包装心跳处理功能

public HeartbeatHandler(ChannelHandler handler) {
    super(handler);
}

增加多信息处理功能

public MultiMessageHandler(ChannelHandler handler) {
    super(handler);
}

初始服务端，设置dubbo编码器DubboCountCodec，设置连接超时时间，获取当前地址信息，获取绑定地址信息，设置客户端连接数量，设置连接空闲超时时间，最后获取之前数据存储器中设置的线程池。

public AbstractServer(URL url, ChannelHandler handler) throws RemotingException {
    super(url, handler);
    localAddress = getUrl().toInetSocketAddress();

    String bindIp = getUrl().getParameter(Constants.BIND_IP_KEY, getUrl().getHost());
    int bindPort = getUrl().getParameter(Constants.BIND_PORT_KEY, getUrl().getPort());
    if (url.getParameter(Constants.ANYHOST_KEY, false) || NetUtils.isInvalidLocalHost(bindIp)) {
        bindIp = Constants.ANYHOST_VALUE;
    }
    bindAddress = new InetSocketAddress(bindIp, bindPort);
    this.accepts = url.getParameter(Constants.ACCEPTS_KEY, Constants.DEFAULT_ACCEPTS);
    this.idleTimeout = url.getParameter(Constants.IDLE_TIMEOUT_KEY, Constants.DEFAULT_IDLE_TIMEOUT);
    try {
        doOpen();
        if (logger.isInfoEnabled()) {
            logger.info("Start " + getClass().getSimpleName() + " bind " + getBindAddress() + ", export " + getLocalAddress());
        }
    } catch (Throwable t) {
        throw new RemotingException(url.toInetSocketAddress(), null, "Failed to bind " + getClass().getSimpleName()
                + " on " + getLocalAddress() + ", cause: " + t.getMessage(), t);
    }
    //fixme replace this with better method
    DataStore dataStore = ExtensionLoader.getExtensionLoader(DataStore.class).getDefaultExtension();
    executor = (ExecutorService) dataStore.get(Constants.EXECUTOR_SERVICE_COMPONENT_KEY, Integer.toString(url.getPort()));
}

public AbstractEndpoint(URL url, ChannelHandler handler) {
    super(url, handler);
    this.codec = getChannelCodec(url);
    this.timeout = url.getPositiveParameter(Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT);
    this.connectTimeout = url.getPositiveParameter(Constants.CONNECT_TIMEOUT_KEY, Constants.DEFAULT_CONNECT_TIMEOUT);
}

public AbstractPeer(URL url, ChannelHandler handler) {
    if (url == null) {
        throw new IllegalArgumentException("url == null");
    }
    if (handler == null) {
        throw new IllegalArgumentException("handler == null");
    }
    this.url = url;
    this.handler = handler;
}

开启服务端监听服务

protected void doOpen() throws Throwable {
    bootstrap = new ServerBootstrap();

    bossGroup = new NioEventLoopGroup(1, new DefaultThreadFactory("NettyServerBoss", true));
    workerGroup = new NioEventLoopGroup(getUrl().getPositiveParameter(Constants.IO_THREADS_KEY, Constants.DEFAULT_IO_THREADS),
            new DefaultThreadFactory("NettyServerWorker", true));

    final NettyServerHandler nettyServerHandler = new NettyServerHandler(getUrl(), this);
    channels = nettyServerHandler.getChannels();

    bootstrap.group(bossGroup, workerGroup)
            .channel(NioServerSocketChannel.class)
            .childOption(ChannelOption.TCP_NODELAY, Boolean.TRUE)
            .childOption(ChannelOption.SO_REUSEADDR, Boolean.TRUE)
            .childOption(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT)
            .childHandler(new ChannelInitializer<NioSocketChannel>() {
                @Override
                protected void initChannel(NioSocketChannel ch) throws Exception {
                    // FIXME: should we use getTimeout()?
                    int idleTimeout = UrlUtils.getIdleTimeout(getUrl());
                    NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec(), getUrl(), NettyServer.this);
                    ch.pipeline()//.addLast("logging",new LoggingHandler(LogLevel.INFO))//for debug
                            .addLast("decoder", adapter.getDecoder())
                            .addLast("encoder", adapter.getEncoder())
                            .addLast("server-idle-handler", new IdleStateHandler(0, 0, idleTimeout, MILLISECONDS))
                            .addLast("handler", nettyServerHandler);
                }
            });
    // bind
    ChannelFuture channelFuture = bootstrap.bind(getBindAddress());
    channelFuture.syncUninterruptibly();
    channel = channelFuture.channel();

}