netty案例,netty4.1中级拓展篇十二《Netty流量整形数据流速率控制分析与实战》

2019/08/27

前言介绍

你是否使用过某盘,在前几年我们使用的时候速度飞快,上传下载嗖嗖嗖。但是近年来只要不办会员,速度慢的像蜗牛,当然人家也得赚钱我们能理解。那么这样的限速是怎么实现的呢,我们这个案例使用Netty的流量整形进行限速传输,测试过程中当你把流量整形功能去掉后你就是年费VIP。

流量整形(Traffic Shaping)是一种主动调整流量输出速率的措施。一个典型应用是基于下游网络结点的TP指标来控制本地流量的输出。流量整形与流量监管的主要区别在于,流量整形对流量监管中需要丢弃的报文进行缓存——通常是将它们放入缓冲区或队列内,也称流量整形(Traffic Shaping,简称TS)。当令牌桶有足够的令牌时,再均匀的向外发送这些被缓存的报文。流量整形与流量监管的另一区别是,整形可能会增加延迟,而监管几乎不引入额外的延迟。 微信公众号:bugstack虫洞栈

Netty中通过实现抽象类AbstractTrafficShapingHandler,提供了三个流量整形的类;GlobalTrafficShapingHandler、ChannelTrafficShapingHandler、GlobalChannelTrafficShapingHandler;

AbstractTrafficShapingHandler.java 功能介绍
/**
 * <p>AbstractTrafficShapingHandler allows to limit the global bandwidth
 * (see {@link GlobalTrafficShapingHandler}) or per session
 * bandwidth (see {@link ChannelTrafficShapingHandler}), as traffic shaping.
 * It allows you to implement an almost real time monitoring of the bandwidth using
 * the monitors from {@link TrafficCounter} that will call back every checkInterval
 * the method doAccounting of this handler.</p>
 *
 * <p>If you want for any particular reasons to stop the monitoring (accounting) or to change
 * the read/write limit or the check interval, several methods allow that for you:</p>
 * <ul>
 * <li><tt>configure</tt> allows you to change read or write limits, or the checkInterval</li>
 * <li><tt>getTrafficCounter</tt> allows you to have access to the TrafficCounter and so to stop
 * or start the monitoring, to change the checkInterval directly, or to have access to its values.</li>
 * </ul>
 */
public abstract class AbstractTrafficShapingHandler extends ChannelDuplexHandler{...}

AbstractTrafficShapingHandler允许限制全局的带宽(见GlobalTrafficShapingHandler)或者每个session的带宽(见ChannelTrafficShapingHandler)作为流量整形。 它允许你使用TrafficCounter来实现几乎实时的带宽监控,TrafficCounter会在每个检测间期(checkInterval)调用这个处理器的doAccounting方法。

如果你有任何特别的原因想要停止监控(计数)或者改变读写的限制或者改变检测间期(checkInterval),可以使用如下方法:

  1. configure:允许你改变读或写的限制,或者检测间期(checkInterval);
  2. getTrafficCounter:允许你获得TrafficCounter,并可以停止或启动监控,直接改变检测间期(checkInterval),或去访问它的值。

TrafficCounter:对读和写的字节进行计数以用于限制流量。 它会根据给定的检测间期周期性的计算统计入站和出站的流量,并会回调AbstractTrafficShapingHandler的doAccounting方法。 如果检测间期(checkInterval)是0,将不会进行计数并且统计只会在每次读或写操作时进行计算。

GlobalTrafficShapingHandler.java 全局限制
/**
 * <p>This implementation of the {@link AbstractTrafficShapingHandler} is for global
 * traffic shaping, that is to say a global limitation of the bandwidth, whatever
 * the number of opened channels.</p>
 * <p>Note the index used in {@code OutboundBuffer.setUserDefinedWritability(index, boolean)} is <b>2</b>.</p>
 *
 * <p>The general use should be as follow:</p>
 * <ul>
 * <li><p>Create your unique GlobalTrafficShapingHandler like:</p>
 * <p><tt>GlobalTrafficShapingHandler myHandler = new GlobalTrafficShapingHandler(executor);</tt></p>
 * <p>The executor could be the underlying IO worker pool</p>
 * <p><tt>pipeline.addLast(myHandler);</tt></p>
 *
 * <p><b>Note that this handler has a Pipeline Coverage of "all" which means only one such handler must be created
 * and shared among all channels as the counter must be shared among all channels.</b></p>
 *
 * <p>Other arguments can be passed like write or read limitation (in bytes/s where 0 means no limitation)
 * or the check interval (in millisecond) that represents the delay between two computations of the
 * bandwidth and so the call back of the doAccounting method (0 means no accounting at all).</p>
 *
 * <p>A value of 0 means no accounting for checkInterval. If you need traffic shaping but no such accounting,
 * it is recommended to set a positive value, even if it is high since the precision of the
 * Traffic Shaping depends on the period where the traffic is computed. The highest the interval,
 * the less precise the traffic shaping will be. It is suggested as higher value something close
 * to 5 or 10 minutes.</p>
 *
 * <p>maxTimeToWait, by default set to 15s, allows to specify an upper bound of time shaping.</p>
 * </li>
 * <li>In your handler, you should consider to use the {@code channel.isWritable()} and
 * {@code channelWritabilityChanged(ctx)} to handle writability, or through
 * {@code future.addListener(new GenericFutureListener())} on the future returned by
 * {@code ctx.write()}.</li>
 * <li><p>You shall also consider to have object size in read or write operations relatively adapted to
 * the bandwidth you required: for instance having 10 MB objects for 10KB/s will lead to burst effect,
 * while having 100 KB objects for 1 MB/s should be smoothly handle by this TrafficShaping handler.</p></li>
 * <li><p>Some configuration methods will be taken as best effort, meaning
 * that all already scheduled traffics will not be
 * changed, but only applied to new traffics.</p>
 * So the expected usage of those methods are to be used not too often,
 * accordingly to the traffic shaping configuration.</li>
 * </ul>
 *
 * Be sure to call {@link #release()} once this handler is not needed anymore to release all internal resources.
 * This will not shutdown the {@link EventExecutor} as it may be shared, so you need to do this by your own.
 */
@Sharable
public class GlobalTrafficShapingHandler extends AbstractTrafficShapingHandler {}

这实现了AbstractTrafficShapingHandler的全局流量整形,也就是说它限制了全局的带宽,无论开启了几个channel。 注意『 OutboundBuffer.setUserDefinedWritability(index, boolean)』中索引使用’2’。

一般用途如下: 创建一个唯一的GlobalTrafficShapingHandler

GlobalTrafficShapingHandler myHandler = new GlobalTrafficShapingHandler(executor);
pipeline.addLast(myHandler);

executor可以是底层的IO工作池

注意,这个处理器是覆盖所有管道的,这意味着只有一个处理器对象会被创建并且作为所有channel间共享的计数器,它必须于所有的channel共享。 所有你可以见到,该类的定义上面有个@Sharable注解。

在你的处理器中,你需要考虑使用『channel.isWritable()』和『channelWritabilityChanged(ctx)』来处理可写性,或通过在ctx.write()返回的future上注册listener来实现。

你还需要考虑读或写操作对象的大小需要和你要求的带宽相对应:比如,你将一个10M大小的对象用于10KB/s的带宽将会导致爆发效果,若你将100KB大小的对象用于在1M/s带宽那么将会被流量整形处理器平滑处理。

一旦不在需要这个处理器时请确保调用『release()』以释放所有内部的资源。这不会关闭EventExecutor,因为它可能是共享的,所以这需要你自己做。

GlobalTrafficShapingHandler中持有一个Channel的哈希表,用于存储当前应用所有的Channel:

private final ConcurrentMap<Integer, PerChannel> channelQueues = PlatformDependent.newConcurrentHashMap();

key为Channel的hashCode;value是一个PerChannel对象。 PerChannel对象中维护有该Channel的待发送数据的消息队列(ArrayDeque messagesQueue)。

ChannelTrafficShapingHandler.java 功能介绍
/**
 * <p>This implementation of the {@link AbstractTrafficShapingHandler} is for channel
 * traffic shaping, that is to say a per channel limitation of the bandwidth.</p>
 * <p>Note the index used in {@code OutboundBuffer.setUserDefinedWritability(index, boolean)} is <b>1</b>.</p>
 *
 * <p>The general use should be as follow:</p>
 * <ul>
 * <li><p>Add in your pipeline a new ChannelTrafficShapingHandler.</p>
 * <p><tt>ChannelTrafficShapingHandler myHandler = new ChannelTrafficShapingHandler();</tt></p>
 * <p><tt>pipeline.addLast(myHandler);</tt></p>
 *
 * <p><b>Note that this handler has a Pipeline Coverage of "one" which means a new handler must be created
 * for each new channel as the counter cannot be shared among all channels.</b>.</p>
 *
 * <p>Other arguments can be passed like write or read limitation (in bytes/s where 0 means no limitation)
 * or the check interval (in millisecond) that represents the delay between two computations of the
 * bandwidth and so the call back of the doAccounting method (0 means no accounting at all).</p>
 *
 * <p>A value of 0 means no accounting for checkInterval. If you need traffic shaping but no such accounting,
 * it is recommended to set a positive value, even if it is high since the precision of the
 * Traffic Shaping depends on the period where the traffic is computed. The highest the interval,
 * the less precise the traffic shaping will be. It is suggested as higher value something close
 * to 5 or 10 minutes.</p>
 *
 * <p>maxTimeToWait, by default set to 15s, allows to specify an upper bound of time shaping.</p>
 * </li>
 * <li>In your handler, you should consider to use the {@code channel.isWritable()} and
 * {@code channelWritabilityChanged(ctx)} to handle writability, or through
 * {@code future.addListener(new GenericFutureListener())} on the future returned by
 * {@code ctx.write()}.</li>
 * <li><p>You shall also consider to have object size in read or write operations relatively adapted to
 * the bandwidth you required: for instance having 10 MB objects for 10KB/s will lead to burst effect,
 * while having 100 KB objects for 1 MB/s should be smoothly handle by this TrafficShaping handler.</p></li>
 * <li><p>Some configuration methods will be taken as best effort, meaning
 * that all already scheduled traffics will not be
 * changed, but only applied to new traffics.</p>
 * <p>So the expected usage of those methods are to be used not too often,
 * accordingly to the traffic shaping configuration.</p></li>
 * </ul>
 */
public class ChannelTrafficShapingHandler extends AbstractTrafficShapingHandler {...}

ChannelTrafficShapingHandler是针对单个Channel的流量整形,和GlobalTrafficShapingHandler的思想是一样的。只是实现中没有对全局概念的检测,仅检测了当前这个Channel的数据。 这里就不再赘述了。

GlobalChannelTrafficShapingHandler.java 功能介绍
/**
 * This implementation of the {@link AbstractTrafficShapingHandler} is for global
 * and per channel traffic shaping, that is to say a global limitation of the bandwidth, whatever
 * the number of opened channels and a per channel limitation of the bandwidth.<br><br>
 * This version shall not be in the same pipeline than other TrafficShapingHandler.<br><br>
 *
 * The general use should be as follow:<br>
 * <ul>
 * <li>Create your unique GlobalChannelTrafficShapingHandler like:<br><br>
 * <tt>GlobalChannelTrafficShapingHandler myHandler = new GlobalChannelTrafficShapingHandler(executor);</tt><br><br>
 * The executor could be the underlying IO worker pool<br>
 * <tt>pipeline.addLast(myHandler);</tt><br><br>
 *
 * <b>Note that this handler has a Pipeline Coverage of "all" which means only one such handler must be created
 * and shared among all channels as the counter must be shared among all channels.</b><br><br>
 *
 * Other arguments can be passed like write or read limitation (in bytes/s where 0 means no limitation)
 * or the check interval (in millisecond) that represents the delay between two computations of the
 * bandwidth and so the call back of the doAccounting method (0 means no accounting at all).<br>
 * Note that as this is a fusion of both Global and Channel Traffic Shaping, limits are in 2 sets,
 * respectively Global and Channel.<br><br>
 *
 * A value of 0 means no accounting for checkInterval. If you need traffic shaping but no such accounting,
 * it is recommended to set a positive value, even if it is high since the precision of the
 * Traffic Shaping depends on the period where the traffic is computed. The highest the interval,
 * the less precise the traffic shaping will be. It is suggested as higher value something close
 * to 5 or 10 minutes.<br><br>
 *
 * maxTimeToWait, by default set to 15s, allows to specify an upper bound of time shaping.<br><br>
 * </li>
 * <li>In your handler, you should consider to use the {@code channel.isWritable()} and
 * {@code channelWritabilityChanged(ctx)} to handle writability, or through
 * {@code future.addListener(new GenericFutureListener())} on the future returned by
 * {@code ctx.write()}.</li>
 * <li>You shall also consider to have object size in read or write operations relatively adapted to
 * the bandwidth you required: for instance having 10 MB objects for 10KB/s will lead to burst effect,
 * while having 100 KB objects for 1 MB/s should be smoothly handle by this TrafficShaping handler.<br><br></li>
 * <li>Some configuration methods will be taken as best effort, meaning
 * that all already scheduled traffics will not be
 * changed, but only applied to new traffics.<br>
 * So the expected usage of those methods are to be used not too often,
 * accordingly to the traffic shaping configuration.</li>
 * </ul><br>
 *
 * Be sure to call {@link #release()} once this handler is not needed anymore to release all internal resources.
 * This will not shutdown the {@link EventExecutor} as it may be shared, so you need to do this by your own.
 */
@Sharable
public class GlobalChannelTrafficShapingHandler extends AbstractTrafficShapingHandler {...}

相比于GlobalTrafficShapingHandler增加了一个误差概念,以平衡各个Channel间的读/写操作。也就是说,使得各个Channel间的读/写操作尽量均衡。比如,尽量避免不同Channel的大数据包都延迟近乎一样的是时间再操作,以及如果小数据包在一个大数据包后才发送,则减少该小数据包的延迟发送时间等。。

开发环境

  1. jdk1.8【jdk1.7以下只能部分支持netty】
  2. Netty4.1.36.Final【netty3.x 4.x 5每次的变化较大,接口类名也随着变化】

代码示例

itstack-demo-netty-2-12
└── src
    ├── main
       └── java
           └── org.itstack.demo.netty
               ├── client
               	├── MyChannelInitializer.java
               	├── MyClientHandler.java
               	└── NettyClient.java
               └── server
               	├── common
               		└── MyServerCommonHandler.java	
               	├── MyChannelInitializer.java
               	├── MyServerHandler.java	
               	└── NettyServer.java
    
    └── test
         └── java
             └── org.itstack.demo.test
                 └── ApiTest.java
**部分重点代码块讲解,获取全部代码,关注公众号:bugstack虫洞栈 回复netty源码**
client/MyChannelInitializer.java 增加Channel流量整形配置,速率设置为10bytes/s
/**
 * 虫洞栈:https://bugstack.cn
 * 公众号:bugstack虫洞栈  {获取学习源码}
 * Create by fuzhengwei on 2019
 */
public class MyChannelInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel channel) throws Exception {
        //流量整形
        channel.pipeline().addLast(new ChannelTrafficShapingHandler(10, 10));
        // 基于换行符号
        channel.pipeline().addLast(new LineBasedFrameDecoder(1024));
        // 解码转String,注意调整自己的编码格式GBK、UTF-8
        channel.pipeline().addLast(new StringDecoder(Charset.forName("GBK")));
        // 解码转String,注意调整自己的编码格式GBK、UTF-8
        channel.pipeline().addLast(new StringEncoder(Charset.forName("GBK")));
        // 在管道中添加我们自己的接收数据实现方法
        channel.pipeline().addLast(new MyClientHandler());
    }

}
server/common/MyServerCommonHandler.java 提供抽象类,监控发送速率以及获取发送状态
/**
 * 虫洞栈:https://bugstack.cn
 * 公众号:bugstack虫洞栈 | 欢迎关注并获取专题&源码
 * Create by fuzhengwei on 2019
 */
public abstract class MyServerCommonHandler extends SimpleChannelInboundHandler<String> {

    protected boolean sentFlag;
    private Runnable counterTask;
    private AtomicLong consumeMsgLength = new AtomicLong();
    private long priorProgress;

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        counterTask = () -> {
            while (true) {
                try {
                    Thread.sleep(500);
                    long length = consumeMsgLength.getAndSet(0);
                    if (0 == length) continue;
                    System.out.println("数据发送速率(KB/S):" + length);
                } catch (InterruptedException ignored) {
                }
            }
        };
        super.handlerAdded(ctx);
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        sendData(ctx);
        //启动监控线程
        new Thread(counterTask).start();
    }

    protected abstract void sendData(ChannelHandlerContext ctx);

    protected ChannelProgressivePromise getChannelProgressivePromise(ChannelHandlerContext ctx, Consumer<ChannelProgressiveFuture> completedAction) {
        ChannelProgressivePromise channelProgressivePromise = ctx.newProgressivePromise();
        channelProgressivePromise.addListener(new ChannelProgressiveFutureListener() {
            @Override
            public void operationProgressed(ChannelProgressiveFuture future, long progress, long total) throws Exception {
                consumeMsgLength.addAndGet(progress - priorProgress);
                priorProgress = progress;
            }

            @Override
            public void operationComplete(ChannelProgressiveFuture future) throws Exception {
                sentFlag = false;
                if (future.isSuccess()) {
                    System.out.println("微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!");
                    priorProgress -= 10;
                    Optional.ofNullable(completedAction).ifPresent(action -> action.accept(future));
                } else {
                    System.out.println("微信公众号:bugstack虫洞栈 | 提醒,消息发送失败!");
                    future.cause().printStackTrace();
                }
            }
        });
        return channelProgressivePromise;
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        System.out.println("微信公众号:bugstack虫洞栈 | NettyServer接收到消息:" + msg);
    }

}
server/MyChannelInitializer.java 增加全局流量整形配置,速率设置为10bytes/s
/**
 * 虫洞栈:https://bugstack.cn
 * 公众号:bugstack虫洞栈 | 欢迎关注并获取专题&源码
 * Create by fuzhengwei on 2019
 */
public class MyChannelInitializer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel channel) {

        // 基于换行符号
        channel.pipeline().addLast(new LineBasedFrameDecoder(1024));
        // 流量整形;writeLimit/readLimit{0 or a limit in bytes/s}
        channel.pipeline().addLast(new GlobalTrafficShapingHandler(channel.eventLoop().parent(), 10, 10));
        // 解码转String,注意调整自己的编码格式GBK、UTF-8
        channel.pipeline().addLast(new StringDecoder(Charset.forName("GBK")));
        // 解码转String,注意调整自己的编码格式GBK、UTF-8
        channel.pipeline().addLast(new StringEncoder(Charset.forName("GBK")));
        // 在管道中添加我们自己的接收数据实现方法
        channel.pipeline().addLast(new MyServerHandler());

    }

}

server/MyServerHandler.java 处理消息验证是否可以发送ctx.channel().isWritable()
/**
 * 虫洞栈:https://bugstack.cn
 * 公众号:bugstack虫洞栈 | 欢迎关注并获取专题&源码
 * Create by fuzhengwei on 2019
 */
public class MyServerHandler extends MyServerCommonHandler {

    @Override
    protected void sendData(ChannelHandlerContext ctx) {
        sentFlag = true;
        ctx.writeAndFlush( "111111111122222222223333333333\r\n", getChannelProgressivePromise(ctx, new Consumer<ChannelProgressiveFuture>() {
            @Override
            public void accept(ChannelProgressiveFuture channelProgressiveFuture) {
                if (ctx.channel().isWritable() && !sentFlag) {
                    sendData(ctx);
                }
            }
        }));
    }

}

测试结果

启动服务端NettyServer 可以看到速率已经被限制
itstack-demo-netty server start done. {关注公众号:bugstack虫洞栈 | 获取专题案例源码}
微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!
数据发送速率(KB/S)32
微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!
数据发送速率(KB/S)10
微信公众号:bugstack虫洞栈 | NettyServer接收到消息:876d251b-aba8-481a-81d0-e123a4c42214
微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!
数据发送速率(KB/S)10
微信公众号:bugstack虫洞栈 | NettyServer接收到消息:250d53fb-acc3-4390-b5c5-a660577fff6f
微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!
数据发送速率(KB/S)10
微信公众号:bugstack虫洞栈 | NettyServer接收到消息:89cad8a0-8e5b-44ef-812b-39c4b2d2e0fb
微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!
数据发送速率(KB/S)10
微信公众号:bugstack虫洞栈 | NettyServer接收到消息:e951ca01-a583-4c20-b884-5c272b1cc7a4
微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!
数据发送速率(KB/S)10
微信公众号:bugstack虫洞栈 | NettyServer接收到消息:4b13d77c-188f-4613-9cd9-94a2a7751932
微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!
数据发送速率(KB/S)10
微信公众号:bugstack虫洞栈 | 提醒,消息发送成功!
微信公众号:bugstack虫洞栈 | NettyServer接收到消息:fdc5378c-a594-4be8-885d-4caa7ecccd82
数据发送速率(KB/S)10

Process finished with exit code -1
启动客户端NettyClient 可以看到速率已经被限制
itstack-demo-netty client start done. {关注公众号:bugstack虫洞栈 | 获取专题案例源码}
微信公众号:bugstack虫洞栈 | NettyClient接收到消息:111111111122222222223333333333 length30
微信公众号:bugstack虫洞栈 | NettyClient接收到消息:111111111122222222223333333333 length30
微信公众号:bugstack虫洞栈 | NettyClient接收到消息:111111111122222222223333333333 length30
微信公众号:bugstack虫洞栈 | NettyClient接收到消息:111111111122222222223333333333 length30
微信公众号:bugstack虫洞栈 | NettyClient接收到消息:111111111122222222223333333333 length30
微信公众号:bugstack虫洞栈 | NettyClient接收到消息:111111111122222222223333333333 length30
微信公众号:bugstack虫洞栈 | NettyClient接收到消息:111111111122222222223333333333 length30
微信公众号:bugstack虫洞栈 | NettyClient接收到消息:111111111122222222223333333333 length30

Process finished with exit code -1

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