XXL-RPC原理分析

背景

RPC(Remote Procedure Call Protocol,远程过程调用),调用远程服务就像调用本地服务,在提供远程调用能力时不损失本地调用的语义简洁性;

一般公司,尤其是大型互联网公司内部系统由上千上万个服务组成,不同的服务部署在不同机器,跑在不同的JVM上,此时需要解决两个问题:

  • 1、如果我需要依赖别人的服务,但是别人的服务在远程机器上,我该如何调用?
  • 2、如果其他团队需要使用我的服务,我该怎样发布自己的服务供他人调用?

“XXL-RPC”可以高效的解决这个问题:

  • 1、如何调用:只需要知晓远程服务的stub和地址,即可方便的调用远程服务,同时调用透明化,就像调用本地服务一样简单;
  • 2、如何发布:只需要提供自己服务的stub和地址,别人即可方便的调用我的服务,在开启注册中心的情况下服务动态发现,只需要提供服务的stub即可;

客户端(Client): 服务的调用方。

服务端(Server):真正的服务提供者。

客户端Stub:存放服务端的地址消息,再将客户端的请求参数打包成网络消息,然后通过网络远程发送给服务方。

服务端Stub:接收客户端发送过来的消息,将消息解包,并调用本地的方法。

Stub封装了远程调用的一些细节,使开发者进行远程调用的时候,就像调用本地接口一样。

客户端stub

代码位置参考(可在idea中全局搜索)

服务注册与发现 :

  每隔10s钟服务就会像注册中心注册一下,用来更新updateTime

    参考代码: boolean ret = registryBaseClient.registry(new ArrayList<XxlRpcAdminRegistryDataParamVO>(registryData));

    心跳检测:不断更新updateTime,与当前时间差距30S就会删除:

    参考代码:xxlRpcRegistryDataDao.cleanData(registryBeatTime * 3);

  服务发现是在客户端本地发现的,

    参考代码:invokerFactory.getRegister().discovery(serviceKey);

      会有轮询去请求注册中心,更新本地缓存 如服务被禁用(discoveryData) 且注册中心从文件xxl.rpc.registry.data.filepath中拿,会有线程维护文件和db的一致性

    参考代码:com.xxl.rpc.core.registry.impl.xxlrpcadmin.XxlRpcAdminRegistryClient#refreshDiscoveryData

  检查注册中心数据 不断的从本地队列拿数据registryQueue.take();去check注册中心的数据

    参考代码:checkRegistryDataAndSendMessage(xxlRpcRegistryData);

负载均衡 finalAddress = loadBalance.xxlRpcInvokerRouter.route(serviceKey, addressSet);

发送请求 clientInstance.asyncSend(finalAddress, xxlRpcRequest);

序列化 byte[] requestBytes = serializer.serialize(xxlRpcRequest);

注册中心高可用:如果想要注册中心高可用:简单点,使用Nginx代理,服务配置的注册中心是Nginx代理的地址

取消注册中心 :“@XxlRpcReference” 中address参数 注解参数服务远程地址,ip:port 格式;选填;非空时将会优先实用该服务地址,为空时会从注册中心服务地址发现;

Spring后置处理器 提供代理对象,封装底层通信细节,来代替所有业务调用方直接请求HTTP(Dubbo利用了Spring的Factorybean XXL利用了Spring的PostProcessAfterInstantiation)

服务端stub

反射调用代码位置参考(可在idea中全局搜索)

// invoke + response                
XxlRpcResponse xxlRpcResponse = xxlRpcProviderFactory.invokeService(xxlRpcRequest);                
// response serialize               
byte[] responseBytes = xxlRpcProviderFactory.getSerializerInstance().serialize(xxlRpcResponse);

引用

源码地址:https://gitee.com/xuxueli0323/xxl-rpc?_from=gitee_search

stub理解:https://www.jianshu.com/p/9ccdea882688

XXL对Netty的使用

客户端:NettyConnectClient

package com.xxl.rpc.core.remoting.net.impl.netty.client;

import com.xxl.rpc.core.remoting.invoker.XxlRpcInvokerFactory;
import com.xxl.rpc.core.remoting.net.common.ConnectClient;
import com.xxl.rpc.core.remoting.net.impl.netty.codec.NettyDecoder;
import com.xxl.rpc.core.remoting.net.impl.netty.codec.NettyEncoder;
import com.xxl.rpc.core.remoting.net.impl.netty_http.client.NettyHttpConnectClient;
import com.xxl.rpc.core.remoting.net.params.BaseCallback;
import com.xxl.rpc.core.remoting.net.params.Beat;
import com.xxl.rpc.core.remoting.net.params.XxlRpcRequest;
import com.xxl.rpc.core.remoting.net.params.XxlRpcResponse;
import com.xxl.rpc.core.serialize.Serializer;
import com.xxl.rpc.core.util.IpUtil;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.timeout.IdleStateHandler;

import java.util.concurrent.TimeUnit;

/**
 * netty pooled client
 *
 * @author xuxueli
 */
public class NettyConnectClient extends ConnectClient {
    private static NioEventLoopGroup nioEventLoopGroup;

    private Channel channel;


    @Override
    public void init(String address, final Serializer serializer, final XxlRpcInvokerFactory xxlRpcInvokerFactory) throws Exception {
        // address
        Object[] array = IpUtil.parseIpPort(address);
        String host = (String) array[0];
        int port = (int) array[1];

        // group
        if (nioEventLoopGroup == null) {
            synchronized (NettyHttpConnectClient.class) {
                if (nioEventLoopGroup == null) {
                    nioEventLoopGroup = new NioEventLoopGroup();
                    xxlRpcInvokerFactory.addStopCallBack(new BaseCallback() {
                        @Override
                        public void run() throws Exception {
                            nioEventLoopGroup.shutdownGracefully();
                        }
                    });
                }
            }
        }

        // init
        final NettyConnectClient thisClient = this;
        Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(nioEventLoopGroup)
                .channel(NioSocketChannel.class)
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    public void initChannel(SocketChannel channel) throws Exception {
                        channel.pipeline()
                                .addLast(new IdleStateHandler(0,0,Beat.BEAT_INTERVAL, TimeUnit.SECONDS))    // beat N, close if fail
                                .addLast(new NettyEncoder(XxlRpcRequest.class, serializer))
                                .addLast(new NettyDecoder(XxlRpcResponse.class, serializer))
                                .addLast(new NettyClientHandler(xxlRpcInvokerFactory, thisClient));
                    }
                })
                .option(ChannelOption.TCP_NODELAY, true)
                .option(ChannelOption.SO_KEEPALIVE, true)
                .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000);
        this.channel = bootstrap.connect(host, port).sync().channel();

        // valid
        if (!isValidate()) {
            close();
            return;
        }

        logger.debug(">>>>>>>>>>> xxl-rpc netty client proxy, connect to server success at host:{}, port:{}", host, port);
    }


    @Override
    public boolean isValidate() {
        if (this.channel != null) {
            return this.channel.isActive();
        }
        return false;
    }

    @Override
    public void close() {
        if (this.channel != null && this.channel.isActive()) {
            this.channel.close();        // if this.channel.isOpen()
        }
        logger.debug(">>>>>>>>>>> xxl-rpc netty client close.");
    }


    @Override
    public void send(XxlRpcRequest xxlRpcRequest) throws Exception {
        this.channel.writeAndFlush(xxlRpcRequest).sync();
    }
}
View Code

 服务端:NettyServer

package com.xxl.rpc.core.remoting.net.impl.netty.server;

import com.xxl.rpc.core.remoting.net.Server;
import com.xxl.rpc.core.remoting.net.impl.netty.codec.NettyDecoder;
import com.xxl.rpc.core.remoting.net.impl.netty.codec.NettyEncoder;
import com.xxl.rpc.core.remoting.net.params.Beat;
import com.xxl.rpc.core.remoting.net.params.XxlRpcRequest;
import com.xxl.rpc.core.remoting.net.params.XxlRpcResponse;
import com.xxl.rpc.core.remoting.provider.XxlRpcProviderFactory;
import com.xxl.rpc.core.util.ThreadPoolUtil;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.timeout.IdleStateHandler;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * netty rpc server
 *
 * @author xuxueli 2015-10-29 18:17:14
 */
public class NettyServer extends Server {

    private Thread thread;

    @Override
    public void start(final XxlRpcProviderFactory xxlRpcProviderFactory) throws Exception {

        thread = new Thread(new Runnable() {
            @Override
            public void run() {

                // param
                final ThreadPoolExecutor serverHandlerPool = ThreadPoolUtil.makeServerThreadPool(
                        NettyServer.class.getSimpleName(),
                        xxlRpcProviderFactory.getCorePoolSize(),
                        xxlRpcProviderFactory.getMaxPoolSize());
                EventLoopGroup bossGroup = new NioEventLoopGroup();
                EventLoopGroup workerGroup = new NioEventLoopGroup();

                try {
                    // start server
                    ServerBootstrap bootstrap = new ServerBootstrap();
                    bootstrap.group(bossGroup, workerGroup)
                            .channel(NioServerSocketChannel.class)
                            .childHandler(new ChannelInitializer<SocketChannel>() {
                                @Override
                                public void initChannel(SocketChannel channel) throws Exception {
                                    channel.pipeline()
                                            .addLast(new IdleStateHandler(0,0, Beat.BEAT_INTERVAL*3, TimeUnit.SECONDS))     // beat 3N, close if idle
                                            .addLast(new NettyDecoder(XxlRpcRequest.class, xxlRpcProviderFactory.getSerializerInstance()))
                                            .addLast(new NettyEncoder(XxlRpcResponse.class, xxlRpcProviderFactory.getSerializerInstance()))
                                            .addLast(new NettyServerHandler(xxlRpcProviderFactory, serverHandlerPool));
                                }
                            })
                            .childOption(ChannelOption.TCP_NODELAY, true)
                            .childOption(ChannelOption.SO_KEEPALIVE, true);

                    // bind
                    ChannelFuture future = bootstrap.bind(xxlRpcProviderFactory.getPort()).sync();

                    logger.info(">>>>>>>>>>> xxl-rpc remoting server start success, nettype = {}, port = {}", NettyServer.class.getName(), xxlRpcProviderFactory.getPort());
                    onStarted();

                    // wait util stop
                    future.channel().closeFuture().sync();

                } catch (Exception e) {
                    if (e instanceof InterruptedException) {
                        logger.info(">>>>>>>>>>> xxl-rpc remoting server stop.");
                    } else {
                        logger.error(">>>>>>>>>>> xxl-rpc remoting server error.", e);
                    }
                } finally {

                    // stop
                    try {
                        serverHandlerPool.shutdown();    // shutdownNow
                    } catch (Exception e) {
                        logger.error(e.getMessage(), e);
                    }
                    try {
                        workerGroup.shutdownGracefully();
                        bossGroup.shutdownGracefully();
                    } catch (Exception e) {
                        logger.error(e.getMessage(), e);
                    }

                }
            }
        });
        thread.setDaemon(true);
        thread.start();

    }

    @Override
    public void stop() throws Exception {

        // destroy server thread
        if (thread != null && thread.isAlive()) {
            thread.interrupt();
        }

        // on stop
        onStoped();
        logger.info(">>>>>>>>>>> xxl-rpc remoting server destroy success.");
    }

}
View Code

 

posted @ 2021-06-16 21:04  palapala  阅读(859)  评论(1编辑  收藏  举报