Handwritten RPC Framework Chapter 2 netty Communications

Keywords: Java Netty network log4j

Case introduction
When we implement the rpc framework, we need to choose the communication mode of socket. And we know that in general, socket communication is similar to qq chat, sending messages in the past, and when to reply. But our rpc framework communication, which feels like an http call, needs to be returned in a certain time, otherwise it will break over time.

Here we choose netty as our socket framework and use future to communicate.

Netty is a java open source framework provided by JBOSS. Netty provides an asynchronous, event-driven framework and tools for rapid development of high-performance, high-reliability network servers and client programs. In other words, Netty is a NIO-based client-server programming framework, using Netty can ensure that you quickly and simply develop a network application, such as a client-server application that implements a certain protocol. Netty is equivalent to simplifying and streamlining the programming development process of network applications, such as socket service development based on TCP and UDP. "Fast" and "simple" don't cause maintenance or performance problems. Netty is a well-designed project that absorbs the implementation experience of a variety of protocols (including FTP, SMTP, HTTP and other binary text protocols). Finally, Netty successfully found a way to ensure that it is easy to develop, but also to ensure the performance, stability and scalability of its applications.

Environmental preparation
1,jdk 1.8.0
2,IntelliJ IDEA Community Edition 2018.3.1 x64

Code example

itstack-demo-rpc-02
└── src
    └── main
    │    └── java
    │        └── org.itstack.demo.rpc.network
    │             ├── client
    │             │   ├── ClientSocket.java
    │             │   └── MyClientHandler.java  
    │             ├── codec
    │             │   ├── RpcDecoder.java
    │             │   └── RpcEncoder.java  
    │             ├── future
    │             │   ├── SyncWrite.java 	
    │             │   ├── SyncWriteFuture.java	
    │             │   ├── SyncWriteMap.java	
    │             │   └── WriteFuture.java	
    │             ├── msg
    │             │   ├── Request.java
    │             │   └── Response.java 
    │             ├── server
    │             │   ├── MyServerHandler.java
    │             │   └── ServerSocket.java 	
    │             └── util
    │                 └── SerializationUtil.java 	
    └── test
         └── java
             └── org.itstack.demo.test
                 ├── client
            	 │   └── StartClient.java
                 └── server
            	     └── StartServer.java

ClientSocket.java

package org.itstack.demo.rpc.network.client;

import io.netty.bootstrap.Bootstrap;
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.NioSocketChannel;
import org.itstack.demo.rpc.network.codec.RpcDecoder;
import org.itstack.demo.rpc.network.codec.RpcEncoder;
import org.itstack.demo.rpc.network.msg.Request;
import org.itstack.demo.rpc.network.msg.Response;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class ClientSocket implements Runnable {

    private ChannelFuture future;

    @Override
    public void run() {
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(workerGroup);
            b.channel(NioSocketChannel.class);
            b.option(ChannelOption.AUTO_READ, true);
            b.handler(new ChannelInitializer<SocketChannel>() {
                @Override
                public void initChannel(SocketChannel ch) throws Exception {
                    ch.pipeline().addLast(
                            new RpcDecoder(Response.class),
                            new RpcEncoder(Request.class),
                            new MyClientHandler());
                }
            });
            ChannelFuture f = b.connect("127.0.0.1", 7397).sync();
            this.future = f;
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            workerGroup.shutdownGracefully();
        }
    }

    public ChannelFuture getFuture() {
        return future;
    }

    public void setFuture(ChannelFuture future) {
        this.future = future;
    }
}

MyClientHandler.java

package org.itstack.demo.rpc.network.client;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import org.itstack.demo.rpc.network.future.SyncWriteFuture;
import org.itstack.demo.rpc.network.future.SyncWriteMap;
import org.itstack.demo.rpc.network.msg.Response;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class MyClientHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object obj) throws Exception {
        Response msg = (Response) obj;
        String requestId = msg.getRequestId();
        SyncWriteFuture future = (SyncWriteFuture) SyncWriteMap.syncKey.get(requestId);
        if (future != null) {
            future.setResponse(msg);
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }

}

RpcDecoder.java

package org.itstack.demo.rpc.network.codec;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import org.itstack.demo.rpc.network.util.SerializationUtil;

import java.util.List;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class RpcDecoder extends ByteToMessageDecoder {

    private Class<?> genericClass;

    public RpcDecoder(Class<?> genericClass) {
        this.genericClass = genericClass;
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) {
        if (in.readableBytes() < 4) {
            return;
        }
        in.markReaderIndex();
        int dataLength = in.readInt();
        if (in.readableBytes() < dataLength) {
            in.resetReaderIndex();
            return;
        }
        byte[] data = new byte[dataLength];
        in.readBytes(data);
        out.add(SerializationUtil.deserialize(data, genericClass));
    }

}

RpcEncoder.java

package org.itstack.demo.rpc.network.codec;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;
import org.itstack.demo.rpc.network.util.SerializationUtil;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class RpcEncoder extends MessageToByteEncoder {

    private Class<?> genericClass;

    public RpcEncoder(Class<?> genericClass) {
        this.genericClass = genericClass;
    }

    @Override
    protected void encode(ChannelHandlerContext ctx, Object in, ByteBuf out)  {
        if (genericClass.isInstance(in)) {
            byte[] data = SerializationUtil.serialize(in);
            out.writeInt(data.length);
            out.writeBytes(data);
        }
    }

}

SyncWrite.java

package org.itstack.demo.rpc.network.future;

import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import org.itstack.demo.rpc.network.msg.Request;
import org.itstack.demo.rpc.network.msg.Response;

import java.util.UUID;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class SyncWrite {

    public Response writeAndSync(final Channel channel, final Request request, final long timeout) throws Exception {

        if (channel == null) {
            throw new NullPointerException("channel");
        }
        if (request == null) {
            throw new NullPointerException("request");
        }
        if (timeout <= 0) {
            throw new IllegalArgumentException("timeout <= 0");
        }

        String requestId = UUID.randomUUID().toString();
        request.setRequestId(requestId);

        WriteFuture<Response> future = new SyncWriteFuture(request.getRequestId());
        SyncWriteMap.syncKey.put(request.getRequestId(), future);

        Response response = doWriteAndSync(channel, request, timeout, future);

        SyncWriteMap.syncKey.remove(request.getRequestId());
        return response;
    }

    private Response doWriteAndSync(final Channel channel, final Request request, final long timeout, final WriteFuture<Response> writeFuture) throws Exception {

        channel.writeAndFlush(request).addListener(new ChannelFutureListener() {
            public void operationComplete(ChannelFuture future) throws Exception {
                writeFuture.setWriteResult(future.isSuccess());
                writeFuture.setCause(future.cause());
                //Failure to remove
                if (!writeFuture.isWriteSuccess()) {
                    SyncWriteMap.syncKey.remove(writeFuture.requestId());
                }
            }
        });

        Response response = writeFuture.get(timeout, TimeUnit.MILLISECONDS);
        if (response == null) {
            if (writeFuture.isTimeout()) {
                throw new TimeoutException();
            } else {
                // write exception
                throw new Exception(writeFuture.cause());
            }
        }
        return response;
    }

}

SyncWriteFuture.java

package org.itstack.demo.rpc.network.future;


import org.itstack.demo.rpc.network.msg.Response;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class SyncWriteFuture implements WriteFuture<Response> {

    private CountDownLatch latch = new CountDownLatch(1);
    private final long begin = System.currentTimeMillis();
    private long timeout;
    private Response response;
    private final String requestId;
    private boolean writeResult;
    private Throwable cause;
    private boolean isTimeout = false;

    public SyncWriteFuture(String requestId) {
        this.requestId = requestId;
    }

    public SyncWriteFuture(String requestId, long timeout) {
        this.requestId = requestId;
        this.timeout = timeout;
        writeResult = true;
        isTimeout = false;
    }


    public Throwable cause() {
        return cause;
    }

    public void setCause(Throwable cause) {
        this.cause = cause;
    }

    public boolean isWriteSuccess() {
        return writeResult;
    }

    public void setWriteResult(boolean result) {
        this.writeResult = result;
    }

    public String requestId() {
        return requestId;
    }

    public Response response() {
        return response;
    }

    public void setResponse(Response response) {
        this.response = response;
        latch.countDown();
    }

    public boolean cancel(boolean mayInterruptIfRunning) {
        return true;
    }

    public boolean isCancelled() {
        return false;
    }

    public boolean isDone() {
        return false;
    }

    public Response get() throws InterruptedException, ExecutionException {
        latch.wait();
        return response;
    }

    public Response get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
        if (latch.await(timeout, unit)) {
            return response;
        }
        return null;
    }

    public boolean isTimeout() {
        if (isTimeout) {
            return isTimeout;
        }
        return System.currentTimeMillis() - begin > timeout;
    }
}

SyncWriteMap.java

package org.itstack.demo.rpc.network.future;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class SyncWriteMap {

    public static Map<String, WriteFuture> syncKey = new ConcurrentHashMap<String, WriteFuture>();

}

WriteFuture.java

package org.itstack.demo.rpc.network.future;

import org.itstack.demo.rpc.network.msg.Response;

import java.util.concurrent.Future;

public interface WriteFuture<T> extends Future<T> {

    Throwable cause();

    void setCause(Throwable cause);

    boolean isWriteSuccess();

    void setWriteResult(boolean result);

    String requestId();

    T response();

    void setResponse(Response response);

    boolean isTimeout();


}

Request.java

package org.itstack.demo.rpc.network.msg;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class Request {

    private String requestId;
    private Object result;

    public String getRequestId() {
        return requestId;
    }

    public void setRequestId(String requestId) {
        this.requestId = requestId;
    }

    public Object getResult() {
        return result;
    }

    public void setResult(Object result) {
        this.result = result;
    }

}

Response.java

package org.itstack.demo.rpc.network.msg;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class Response {

    private String requestId;
    private String param;

    public String getRequestId() {
        return requestId;
    }

    public void setRequestId(String requestId) {
        this.requestId = requestId;
    }

    public String getParam() {
        return param;
    }

    public void setParam(String param) {
        this.param = param;
    }

}

MyServerHandler.java

package org.itstack.demo.rpc.network.server;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.ReferenceCountUtil;
import org.itstack.demo.rpc.network.msg.Request;
import org.itstack.demo.rpc.network.msg.Response;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class MyServerHandler extends ChannelInboundHandlerAdapter{

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object obj){
        Request msg = (Request) obj;
        //feedback
        Response request = new Response();
        request.setRequestId(msg.getRequestId());
        request.setParam(msg.getResult() + " The request is successful. Please accept the feedback.");
        ctx.writeAndFlush(request);
        //release
        ReferenceCountUtil.release(msg);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
        ctx.flush();
    }

}

ServerSocket.java

package org.itstack.demo.rpc.network.server;

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 org.itstack.demo.rpc.network.codec.RpcDecoder;
import org.itstack.demo.rpc.network.codec.RpcEncoder;
import org.itstack.demo.rpc.network.msg.Request;
import org.itstack.demo.rpc.network.msg.Response;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class ServerSocket implements Runnable {

    private ChannelFuture f;

    @Override
    public void run() {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch){
                            ch.pipeline().addLast(
                                    new RpcDecoder(Request.class),
                                    new RpcEncoder(Response.class),
                                    new MyServerHandler());
                        }
                    });

            ChannelFuture f = null;
            f = b.bind(7397).sync();
            f.channel().closeFuture().sync();


        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }

    }

}

SerializationUtil.java

package org.itstack.demo.rpc.network.util;

import com.dyuproject.protostuff.LinkedBuffer;
import com.dyuproject.protostuff.ProtostuffIOUtil;
import com.dyuproject.protostuff.Schema;
import com.dyuproject.protostuff.runtime.RuntimeSchema;
import org.objenesis.Objenesis;
import org.objenesis.ObjenesisStd;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Created by fuzhengwei1 on 2016/10/20.
 */
public class SerializationUtil {

    private static Map<Class<?>, Schema<?>> cachedSchema = new ConcurrentHashMap();

    private static Objenesis objenesis = new ObjenesisStd();

    private SerializationUtil() {

    }

    /**
     * Serialization (object - > byte array)
     *
     * @param obj object
     * @return Byte array
     */
    public static <T> byte[] serialize(T obj) {
        Class<T> cls = (Class<T>) obj.getClass();
        LinkedBuffer buffer = LinkedBuffer.allocate(LinkedBuffer.DEFAULT_BUFFER_SIZE);
        try {
            Schema<T> schema = getSchema(cls);
            return ProtostuffIOUtil.toByteArray(obj, schema, buffer);
        } catch (Exception e) {
            throw new IllegalStateException(e.getMessage(), e);
        } finally {
            buffer.clear();
        }
    }

    /**
     * Deserialization (byte array - > object)
     *
     * @param data
     * @param cls
     * @param <T>
     */
    public static <T> T deserialize(byte[] data, Class<T> cls) {
        try {
            T message = objenesis.newInstance(cls);
            Schema<T> schema = getSchema(cls);
            ProtostuffIOUtil.mergeFrom(data, message, schema);
            return message;
        } catch (Exception e) {
            throw new IllegalStateException(e.getMessage(), e);
        }
    }

    private static <T> Schema<T> getSchema(Class<T> cls) {
        Schema<T> schema = (Schema<T>) cachedSchema.get(cls);
        if (schema == null) {
            schema = RuntimeSchema.createFrom(cls);
            cachedSchema.put(cls, schema);
        }
        return schema;
    }

}

StartClient.java

package org.itstack.demo.test.client;

import com.alibaba.fastjson.JSON;
import io.netty.channel.ChannelFuture;
import org.itstack.demo.rpc.network.client.ClientSocket;
import org.itstack.demo.rpc.network.future.SyncWrite;
import org.itstack.demo.rpc.network.msg.Request;
import org.itstack.demo.rpc.network.msg.Response;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class StartClient {

    private static ChannelFuture future;

    public static void main(String[] args) {
        ClientSocket client = new ClientSocket();
        new Thread(client).start();

        while (true) {
            try {
                //Get future, threads have waiting time
                if (null == future) {
                    future = client.getFuture();
                    Thread.sleep(500);
                    continue;
                }
                //Constructing send parameters
                Request request = new Request();
                request.setResult("Query User Information");
                SyncWrite s = new SyncWrite();
                Response response = s.writeAndSync(future.channel(), request, 1000);
                System.out.println("Call result:" + JSON.toJSON(response));
                Thread.sleep(1000);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

}

StartServer.java

package org.itstack.demo.test.server;

import org.itstack.demo.rpc.network.server.ServerSocket;

/**
 * http://www.itstack.org
 * create by fuzhengwei on 2019/5/6
 */
public class StartServer {

    public static void main(String[] args) {
        System.out.println("Start Server Start");
        new Thread(new ServerSocket()).start();
        System.out.println("Start Server Completion");
    }

}

test result

Start StartServer

Start Server Start
//Start Server Completion
log4j:WARN No appenders could be found for logger (io.netty.util.internal.logging.InternalLoggerFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

Start StartClient

log4j:WARN No appenders could be found for logger (io.netty.util.internal.logging.InternalLoggerFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
//Call result:{"param":"The user information request is successful, and the feedback results should be processed.","requestId":"3380f061-2501-49b5-998b-21b5956fe60a"}
//Call result:{"param":"The user information request is successful, and the feedback results should be processed.","requestId":"81c51815-4d92-482c-bd05-e4b6dfa4d3b6"}
//Call result:{"param":"The user information request is successful, and the feedback results should be processed.","requestId":"7af01c4f-a438-47a1-b35c-8e2cd7e4a5e7"}
//Call result:{"param":"The user information request is successful, and the feedback results should be processed.","requestId":"86e38bb1-eccc-4d45-b976-c3b67999e3ab"}
//Call result:{"param":"The user information request is successful, and the feedback results should be processed.","requestId":"7f72002c-3b38-43d9-8452-db8797298899"}
//Call result:{"param":"The user information request is successful, and the feedback results should be processed.","requestId":"d566a7d4-4b0d-426b-8c09-c535ccf8eb09"}

...

Pay attention to bugstack wormhole stack public number to get source code and reply < RPC source code >

Posted by fer0an on Thu, 03 Oct 2019 14:38:23 -0700

Programmer Group

Handwritten RPC Framework Chapter 2 netty Communications

Pay attention to bugstack wormhole stack public number to get source code and reply < RPC source code >

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