在进行 WebSocket 协议连接或者 WebSocket 接口测试的时候,一旦遇到超大连接数量的场景中时,之前使用过的实现 Java-WebSocket 以及 Netty-WebSocket 两种实现就会显示出巨大的性能差距。当然 Netty-WebSocket 就是为了解决性能问题而来的。

so,今天我就来展示一下两个 WebSocket 实现在使用中具体的差异,本文集中在资源占用上,特别是线程占用。

理论差异

Java-WebSocket

据可靠资料显示,两者的差异主要以在管理 WebSocket 连接时使用的线程数不同,以下是使用org.java_websocket.client.WebSocketClient创建 WebSocket 客户端时,它会创建以下几个线程:

这些线程的存在使得WebSocket客户端能够在后台处理连接、发送和接收消息,而不会阻塞主线程。这有助于确保应用程序在与 WebSocket 服务器进行通信时能够保持响应性。

据资料显示不同版本的实现线程是不一样的,这里我没有找到具体的版本差异,也没有进行测试。

Netty-WebSocket

Netty 其实并不存在上面这个问题,因为 WebSocket 连接和线程数并没有强的绑定关系。Netty 只有一个处理事件的 io.netty.channel.EventLoopGroup 需要使用线程池设计,其他均没有设置线程和创建线程的设置。

被测服务

这里我用 Go 写了一个 WebSocket 的服务端,一来省事儿,二来性能高足以应付接下来的测试。服务端代码如下:

// CreateServer  
// @Description: 重建一个WebSocket服务  
// @param port 端口  
// @param path 路径  
func CreateServer(port int, path string) {  

   var upgrader = websocket.Upgrader{  
      ReadBufferSize:   1024,  
      WriteBufferSize:  1024,  
      HandshakeTimeout: 5 * time.Second,  
   }  

   http.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {  
      conn, _ := upgrader.Upgrade(w, r, nil)  
      conn.WriteMessage(websocket.TextMessage, []byte("msg"))  

      for {  
         msgType, msg, err := conn.ReadMessage()  
         if err != nil {  
            log.Println(err)  
            return  
         }  
         fmt.Printf("%s receive: %s\n", conn.RemoteAddr(), string(msg))  

         if err = conn.WriteMessage(msgType, msg); err != nil {  
            log.Println("ffahv")  
            return  
         }  
      }  
   })  

   http.ListenAndServe(":"+strconv.Itoa(port), nil)  
}

单链接对比

空 Java 进程

首先测试一下空的 Java 进行消耗的线程数详情,测试客户端如下:

import com.funtester.frame.SourceCode  

class Empty extends SourceCode{  

    static void main(String[] args) {  
        waitForKey("按任意键退出")  
    }  


}

运行时,进行监控:

空Java进行

Java-WebSocket

只创建 1 个 WebSocket 客户端,测试代码如下:

package com.funtest.websocket

import com.funtester.frame.SourceCode
import com.funtester.socket.WebSocketFunClient

class WebSocket extends SourceCode {

    static String url = "ws://localhost:12345/test"


    static void main(String[] args) {
        def instance = WebSocketFunClient.getInstance(url)
        instance.connect()
        instance.send("Hello FunTester")
        waitForKey("按任意键退出")
    }
}

运行线程监控:

WebSocket单线程

Netty-WebSocket

逻辑同上,代码如下:

package com.funtest.websocket

import com.funtester.frame.SourceCode
import com.funtester.socket.netty.WebSocketConnector
import groovy.util.logging.Log4j2

@Log4j2
class NettySocket extends SourceCode {

    static void main(String[] args) {
        String serverIp = "ws://127.0.0.1";
        int serverPort = 12345;
        def h = {String x ->
            log.info("收到消息:{}", x)
        }
        WebSocketConnector client = new WebSocketConnector(serverIp, serverPort, "/test",h)
        client.connect()
        client.getHandshakeFuture().get()
        client.sendText("Hello FunTester").get()
        waitForKey("按任意键退出")
    }
}

运行时线程监控:

Netty-WebSocket

结论

Java-WebSocket 额外创建了 3 个线程,而 Netty-WebSocket 额外创建了 1 个线程。这里我采取了默认的 io.netty.channel.EventLoopGroup 创建策略。

1000 连接

Netty-WebSocket

测试代码如下:

package com.funtest.websocket  

import com.funtester.frame.SourceCode  
import com.funtester.socket.netty.WebSocketConnector  
import groovy.util.logging.Log4j2  

@Log4j2  
class NettySocket extends SourceCode {  

    static void main(String[] args) {  
        String serverIp = "ws://127.0.0.1";  
        int serverPort = 12345;  
        def h = {String x ->  
            log.info("收到消息:{}", x)  
        }  
        1000.times {  
            WebSocketConnector client = new WebSocketConnector(serverIp, serverPort, "/test", h)  
            client.connect()  
            client.getHandshakeFuture().get()  
            client.sendText("Hello FunTester").get()  
        }  
        waitForKey("按任意键退出")  
    }  
}

运行时线程监控:

Netty1000连接

Java-WebSocket

由于创建实在太慢了,我测试了 100 个连接,测试代码如下:

package com.funtest.websocket  

import com.funtester.frame.SourceCode  
import com.funtester.socket.WebSocketFunClient  

class WebSocket extends SourceCode {  

    static String url = "ws://localhost:12345/test"  


    static void main(String[] args) {  
        100.times {  
            fun {  
                def instance = WebSocketFunClient.getInstance(url)  
                instance.connect()  
                instance.send("Hello FunTester")  
            }  
        }        waitForKey("按任意键退出")  
    }  
}

运行时线程监控:

WebSocket1000连接

Netty 极限

如果我们只是单纯测试连接数量的话,并没有必要创建很多处理 WebSocket 事件的线程,我们可以直接写死成 1 个线程。下面是测试结果:

Netty极限1000连接

结论

Netty 稳如狗!

代码更新

在本次的实践中,我对 Netty-WebSocket 的实现又做了一批更新,主要增加 WebSocket 接口路径和消息处理闭包功能,并且偷偷修复了 BUG。

WebSocketConnector

package com.funtester.socket.netty  

import com.funtester.frame.execute.ThreadPoolUtil  
import groovy.util.logging.Log4j2  
import io.netty.bootstrap.Bootstrap  
import io.netty.channel.*  
import io.netty.channel.group.ChannelGroup  
import io.netty.channel.group.DefaultChannelGroup  
import io.netty.channel.nio.NioEventLoopGroup  
import io.netty.channel.socket.SocketChannel  
import io.netty.channel.socket.nio.NioSocketChannel  
import io.netty.handler.codec.http.DefaultHttpHeaders  
import io.netty.handler.codec.http.HttpClientCodec  
import io.netty.handler.codec.http.HttpObjectAggregator  
import io.netty.handler.codec.http.websocketx.*  
import io.netty.handler.stream.ChunkedWriteHandler  
import io.netty.util.concurrent.GlobalEventExecutor  

@Log4j2  
class WebSocketConnector {  

    static Bootstrap bootstrap = new Bootstrap()  

    /**  
     * 处理事件的线程池  
     */  
    static EventLoopGroup group = new NioEventLoopGroup(ThreadPoolUtil.getFactory("N"))  

    static {  
        bootstrap.group(group).channel(NioSocketChannel.class)  
    }  

    /**  
     * 用于记录和管理所有客户端的channel  
     */    static ChannelGroup clients = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE)  

    WebSocketClientHandshaker handShaker  

    ChannelPromise handshakeFuture  

    String host  

    int port  

    String path  

    /**  
     * 网络通道  
     */  
    Channel channel  

    WebSocketIoHandler handler  

    /**  
     * WebSocket协议类型的模拟客户端连接器构造方法  
     *  
     * @param serverIp  
     * @param serverSocketPort  
     * @param group  
     */    WebSocketConnector(String host, int port, String path, Closure closure = null) {  
        this.host = host  
        this.port = port  
        this.path = path  
        String URL = this.host + ":" + this.port + path  
        URI uri = new URI(URL)  
        handler = new WebSocketIoHandler(WebSocketClientHandshakerFactory.newHandshaker(uri, WebSocketVersion.V13, null, true, new DefaultHttpHeaders()))  
        if (closure != null) handler.closure = closure  
        bootstrap.option(ChannelOption.TCP_NODELAY, true)  
                .option(ChannelOption.SO_KEEPALIVE, true)  
                .handler(new ChannelInitializer<SocketChannel>() {  

                    @Override  
                    protected void initChannel(SocketChannel ch) throws Exception {  
                        ChannelPipeline pipeline = ch.pipeline()  
                        pipeline.addLast(new HttpClientCodec())  
                        pipeline.addLast(new ChunkedWriteHandler())  
                        pipeline.addLast(new HttpObjectAggregator(1024 * 1024))  
                        pipeline.addLast(handler)  
                    }  
                })  
    }  


    /**  
     * 连接  
     */  
    void connect() {  
        try {  
            try {  
                ChannelFuture future = bootstrap.connect(this.host - "ws://" - "wss://", this.port).sync()  
                this.channel = future.channel()  
                clients.add(channel)  
            } catch (e) {  
                log.error("创建channel失败", e)  
            }  
        } catch (Exception e) {  
            log.error("连接服务失败", e)  
        } finally {  
            this.handshakeFuture = handler.handshakeFuture()  
        }  
    }  

    /**  
     * 发送文本消息  
     */  
    ChannelFuture sendText(String msg) {  
        channel.writeAndFlush(new TextWebSocketFrame(msg))  
    }  

    /**  
     * 发送ping消息  
     */  
    ChannelFuture ping() {  
        channel.writeAndFlush(new PingWebSocketFrame())  
    }  

    /**  
     * 关闭  
     */  
    void close() {  
        group.shutdownGracefully()  
    }  

}

WebSocketIoHandler

package com.funtester.socket.netty  

import groovy.util.logging.Log4j2  
import io.netty.channel.*  
import io.netty.channel.group.ChannelGroup  
import io.netty.channel.group.DefaultChannelGroup  
import io.netty.handler.codec.http.FullHttpResponse  
import io.netty.handler.codec.http.websocketx.*  
import io.netty.handler.timeout.IdleState  
import io.netty.handler.timeout.IdleStateEvent  
import io.netty.util.concurrent.GlobalEventExecutor  

/**  
 * WebSocket协议类型的模拟客户端IO处理器类  
 */  
@Log4j2  
class WebSocketIoHandler extends SimpleChannelInboundHandler<Object> {  

    /**  
     * 用于记录和管理所有客户端的channel  
     */    private ChannelGroup clients = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE)  

    private final WebSocketClientHandshaker handShaker  

    Closure closure  

    private ChannelPromise handshakeFuture  

    WebSocketIoHandler(WebSocketClientHandshaker handShaker) {  
        this.handShaker = handShaker  
    }  

    ChannelFuture handshakeFuture() {  
        return handshakeFuture  
    }  

    @Override  
    void handlerAdded(ChannelHandlerContext ctx) {  
        handshakeFuture = ctx.newPromise()  
    }  

    @Override  
    void channelActive(ChannelHandlerContext ctx) {  
        handShaker.handshake(ctx.channel());  
    }  

    @Override  
    void channelInactive(ChannelHandlerContext ctx) {  
        ctx.close()  
        try {  
            super.channelInactive(ctx)  
        } catch (Exception e) {  
            log.error("channelInactive 异常.", e)  
        }  
        log.warn("WebSocket链路与服务器连接已断开.")  
    }  

    @Override  
    void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {  
        Channel ch = ctx.channel()  
        if (!handShaker.isHandshakeComplete()) {  
            try {  
                handShaker.finishHandshake(ch, (FullHttpResponse) msg)  
                handshakeFuture.setSuccess()  
            } catch (WebSocketHandshakeException e) {  
                log.warn("WebSocket Client failed to connect", e)  
                handshakeFuture.setFailure(e)  
            }  
            return  
        }  

        WebSocketFrame frame = (WebSocketFrame) msg  
        if (frame instanceof TextWebSocketFrame) {  
            if (closure != null) {  
                TextWebSocketFrame textFrame = (TextWebSocketFrame) frame  
                closure(textFrame.text())  
            }  
        } else if (frame instanceof CloseWebSocketFrame) {  
            log.info("WebSocket Client closing")  
            ch.close()  
        }  
    }  

    @Override  
    void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {  
        log.error("WebSocket链路由于发生异常,与服务器连接已断开.", cause)  
        if (!handshakeFuture.isDone()) {  
            handshakeFuture.setFailure(cause)  
        }  
        ctx.close()  
        super.exceptionCaught(ctx, cause)  
    }  

    @Override  
    void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {  
        if (evt instanceof IdleStateEvent) {  
            IdleStateEvent event = (IdleStateEvent) evt  
            // 如果写通道处于空闲状态,就发送心跳命令  
            if (IdleState.WRITER_IDLE == event.state() || IdleState.READER_IDLE == event.state()) {  
                // 发送心跳数据  
                def channel = ctx.channel()  
                channel.writeAndFlush(new TextWebSocketFrame("dsf"))  
            }  
        } else {  
            super.userEventTriggered(ctx, evt)  
        }  
    }  
}


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