Rocketmq发送消息原理（含事务消息）

最新推荐文章于 2025-02-04 00:21:25 发布

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最新推荐文章于 2025-02-04 00:21:25 发布 · 1.2k 阅读

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#消息队列

在消息队列中，生产者负责发送消息到broker,本文讲解Rocketmq发送消息的实现原理以及一些注意的事项。

一、生产者端的发送流程

大致步骤

1、根据topic从nameserver或本地获取路由信息，队列信息，broker信息等

2、根据重试次数，循环发送消息

3、消息内容组装成RemotingCommand对象，包括请求头和请求体

4、分oneway,sync,async的方式进行发送

5、如果是async,oneway会获取令牌再发送

6、组装请求头，调用netty组件发送消息

7、结果处理

二、broker端接收发送消息请求与处理流程

源码入口

class NettyServerHandler extends SimpleChannelInboundHandler<RemotingCommand> {
  
          //netty监听客户端消息        @Override        protected void channelRead0(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
  
              processMessageReceived(ctx, msg);        }    }

发送消息的请求处理器

public class SendMessageProcessor extends AbstractSendMessageProcessor implements NettyRequestProcessor {
  
      private List<ConsumeMessageHook> consumeMessageHookList;    public SendMessageProcessor(final BrokerController brokerController) {
  
          super(brokerController);    }    @Override    public RemotingCommand processRequest(ChannelHandlerContext ctx,                                          RemotingCommand request) throws RemotingCommandException {
  
          SendMessageContext mqtraceContext;        switch (request.getCode()) {
  
          //消费者消费消息 回执            case RequestCode.CONSUMER_SEND_MSG_BACK:                return this.consumerSendMsgBack(ctx, request);                //发送消息请求            default:                //解析请求头                SendMessageRequestHeader requestHeader = parseRequestHeader(request);                if (requestHeader == null) {
  
                      return null;                }                mqtraceContext = buildMsgContext(ctx, requestHeader);                this.executeSendMessageHookBefore(ctx, request, mqtraceContext);                RemotingCommand response;                //发送消息逻辑                if (requestHeader.isBatch()) {
  
                      response = this.sendBatchMessage(ctx, request, mqtraceContext, requestHeader);                } else {
  
                      response = this.sendMessage(ctx, request, mqtraceContext, requestHeader);                }                this.executeSendMessageHookAfter(response, mqtraceContext);                return response;        }    }}

获取消息存储路径

// 用户目录+store+commitlogprivate String storePathCommitLog = System.getProperty("user.home") + File.separator + "store"        + File.separator + "commitlog";            // CommitLog file size,default is 1Gprivate int mapedFileSizeCommitLog = 1024 * 1024 * 1024;    <