Question

例如，Floodlight openflow堆栈使用Netty作为其IO，并定义了以下Pipeline工厂类。

public class OpenflowPipelineFactory implements ChannelPipelineFactory {

    protected Controller controller;
    protected ThreadPoolExecutor pipelineExecutor;
    protected Timer timer;
    protected IdleStateHandler idleHandler;
    protected ReadTimeoutHandler readTimeoutHandler;

    public OpenflowPipelineFactory(Controller controller,
                                   ThreadPoolExecutor pipelineExecutor) {
        super();
        this.controller = controller;
        this.pipelineExecutor = pipelineExecutor;
        this.timer = new HashedWheelTimer();
        this.idleHandler = new IdleStateHandler(timer, 20, 25, 0);
        this.readTimeoutHandler = new ReadTimeoutHandler(timer, 30);
    }

    @Override
    public ChannelPipeline getPipeline() throws Exception {
        OFChannelState state = new OFChannelState();

        ChannelPipeline pipeline = Channels.pipeline();
        pipeline.addLast("ofmessagedecoder", new OFMessageDecoder());
        pipeline.addLast("ofmessageencoder", new OFMessageEncoder());
        pipeline.addLast("idle", idleHandler);
        pipeline.addLast("timeout", readTimeoutHandler);
        pipeline.addLast("handshaketimeout",
                         new HandshakeTimeoutHandler(state, timer, 15));
        if (pipelineExecutor != null)
            pipeline.addLast("pipelineExecutor",
                             new ExecutionHandler(pipelineExecutor));
        pipeline.addLast("handler", controller.getChannelHandler(state));
        return pipeline;
    }

}

但实际上，由于Floodlight为构造函数的第二个参数赋予null，因此永远不会将执行处理程序和执行程序对象分配给管道。

...
final ServerBootstrap bootstrap = createServerBootStrap();

bootstrap.setOption("reuseAddr", true);
bootstrap.setOption("child.keepAlive", true);
bootstrap.setOption("child.tcpNoDelay", true);
bootstrap.setOption("child.sendBufferSize", Controller.SEND_BUFFER_SIZE);

ChannelPipelineFactory pfact = new OpenflowPipelineFactory(this, null);
bootstrap.setPipelineFactory(pfact);
InetSocketAddress sa = new InetSocketAddress(openFlowPort);
final ChannelGroup cg = new DefaultChannelGroup();
cg.add(bootstrap.bind(sa));
...

我的问题是，“如果没有管道执行器被设置为管道会发生什么？”假设有任何默认的管道执行器？如果是，OrderedMemoryAwareThreadPoolExecutor执行器总是被假设？

提前感谢您，等待Netty和Floodlight专家的一些帮助。

Answer 1

如果ChannelPipeline中没有ExecutionHandler，IO线程将处理所有事件。如果添加了ExecutionHandler，则会在ExecutionHandler之后将事件卸载到处理程序的额外Thread-Pool。这允许阻止操作。

没有Netty管道的执行者。怎么了？

1 个答案: