RocketMQ源码 创建Topic流程源码分析

前言

MQAdminImpl MQ管理组件提供了大量对mq进行管理的工具，其中一个就是创建Topic。它内部实现是通过 mqClient工具从 NameServer拉取当前 Topic对应的路由元数据信息，解析遍历和当前topic有关的 broker高可用分组集合，找到分组中的 master主节点，然后依次对 broker主节点发送创建topic请求。broker 高可用分组的主节点收到请求后，将 topic元数据存储在 TopicConfigManager元数据管理组件中，然后上报当前 broker节点 Topic元数据信息到所有?NameServer节点（统一管理路由数据）。

源码版本：4.9.3

源码架构图

源码分析

创建 topic源码入口

org.apache.rocketmq.client.impl.MQAdminImpl#createTopic(java.lang.String, java.lang.String, int, int) 创建 Topic源码入口，通过 mqClient客户端，从 NameServer获取当前 topic key对应的路由元数据，然后遍历 Broker分组元数据列表，对 broker分组中的主节点，发起创建 topic元数据请求。

    // 创建Topic
    public void createTopic(String key,
                            String newTopic, // topic名称
                            int queueNum,  // 队列数目
                            int topicSysFlag // 系统标志
    ) throws MQClientException {
        try {
            Validators.checkTopic(newTopic);
            Validators.isSystemTopic(newTopic);

            // 从NameServer获取路由数据
            TopicRouteData topicRouteData = this.mQClientFactory.getMQClientAPIImpl().getTopicRouteInfoFromNameServer(key, timeoutMillis);
            List<BrokerData> brokerDataList = topicRouteData.getBrokerDatas();
            if (brokerDataList != null && !brokerDataList.isEmpty()) {
                Collections.sort(brokerDataList);

                boolean createOKAtLeastOnce = false;
                MQClientException exception = null;

                StringBuilder orderTopicString = new StringBuilder();

                // 遍历获取到的broker分组元数据列表
                for (BrokerData brokerData : brokerDataList) {
                    // 找到master节点地址
                    String addr = brokerData.getBrokerAddrs().get(MixAll.MASTER_ID);
                    if (addr != null) {
                        // 封装topic元数据配置
                        TopicConfig topicConfig = new TopicConfig(newTopic);
                        topicConfig.setReadQueueNums(queueNum);
                        topicConfig.setWriteQueueNums(queueNum);
                        topicConfig.setTopicSysFlag(topicSysFlag);

                        boolean createOK = false;
                        for (int i = 0; i < 5; i++) {
                            try {
                                // 往每个broker分组主节点，注册topic元数据
                                this.mQClientFactory.getMQClientAPIImpl().createTopic(addr, key, topicConfig, timeoutMillis);
                                createOK = true;
                                createOKAtLeastOnce = true;
                                break;
                            } catch (Exception e) {
                                if (4 == i) {
                                    exception = new MQClientException("create topic to broker exception", e);
                                }
                            }
                        }

                        if (createOK) {
                            orderTopicString.append(brokerData.getBrokerName());
                            orderTopicString.append(":");
                            orderTopicString.append(queueNum);
                            orderTopicString.append(";");
                        }
                    }
                }

                if (exception != null && !createOKAtLeastOnce) {
                    throw exception;
                }
            } else {
                throw new MQClientException("Not found broker, maybe key is wrong", null);
            }
        } catch (Exception e) {
            throw new MQClientException("create new topic failed", e);
        }
    }

org.apache.rocketmq.client.impl.MQClientAPIImpl#createTopic? 向 broker分组中的主节点发送创建 topic请求的源码，通过 netty网络通信服务器客户端，发送同步阻塞 创建、更新topic的请求。

    // 向指定Broker发送创建Topic创建请求
    public void createTopic(final String addr, final String defaultTopic, final TopicConfig topicConfig,
        final long timeoutMillis)
        throws RemotingException, MQBrokerException, InterruptedException, MQClientException {
        // 封装创建Topic请求头
        CreateTopicRequestHeader requestHeader = new CreateTopicRequestHeader();
        requestHeader.setTopic(topicConfig.getTopicName());
        requestHeader.setDefaultTopic(defaultTopic);
        requestHeader.setReadQueueNums(topicConfig.getReadQueueNums());
        requestHeader.setWriteQueueNums(topicConfig.getWriteQueueNums());
        requestHeader.setPerm(topicConfig.getPerm());
        requestHeader.setTopicFilterType(topicConfig.getTopicFilterType().name());
        requestHeader.setTopicSysFlag(topicConfig.getTopicSysFlag());
        requestHeader.setOrder(topicConfig.isOrder());

        // 请求处理命令对应的请求code为  UPDATE_AND_CREATE_TOPIC
        RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.UPDATE_AND_CREATE_TOPIC, requestHeader);

        // 发送同步阻塞请求
        RemotingCommand response = this.remotingClient.invokeSync(MixAll.brokerVIPChannel(this.clientConfig.isVipChannelEnabled(), addr),
            request, timeoutMillis);
        assert response != null;
        switch (response.getCode()) {
            case ResponseCode.SUCCESS: {
                return;
            }
            default:
                break;
        }

        throw new MQClientException(response.getCode(), response.getRemark());
    }

Borker 接受创建 topic请求

org.apache.rocketmq.broker.processor.AdminBrokerProcessor#processRequest?

1. 解码请求头；
2. 提取、封装 topic元数据信息；
3. 将元数据信息存储到本节点的 TopicConfigManager topic元数据管理组件；
4. 上报 topic元数据信息到所有 NameServer节点。

    @Override
    public RemotingCommand processRequest(ChannelHandlerContext ctx,
        RemotingCommand request) throws RemotingCommandException {
        switch (request.getCode()) {
            // 更新 创建 topic
            case RequestCode.UPDATE_AND_CREATE_TOPIC:
                return this.updateAndCreateTopic(ctx, request);
            case RequestCode.DELETE_TOPIC_IN_BROKER:
                return this.deleteTopic(ctx, request);
    }

    private synchronized RemotingCommand updateAndCreateTopic(ChannelHandlerContext ctx,
        RemotingCommand request) throws RemotingCommandException {
        final RemotingCommand response = RemotingCommand.createResponseCommand(null);
        // 解码请求头
        final CreateTopicRequestHeader requestHeader =
            (CreateTopicRequestHeader) request.decodeCommandCustomHeader(CreateTopicRequestHeader.class);
        log.info("updateAndCreateTopic called by {}", RemotingHelper.parseChannelRemoteAddr(ctx.channel()));

        // 提取topic名称
        String topic = requestHeader.getTopic();

        if (!TopicValidator.validateTopic(topic, response)) {
            return response;
        }
        if (TopicValidator.isSystemTopic(topic, response)) {
            return response;
        }

        // 封装topic元数据
        TopicConfig topicConfig = new TopicConfig(topic);
        // 每个broker节点都有默认数量的读队列和写队列
        topicConfig.setReadQueueNums(requestHeader.getReadQueueNums());
        topicConfig.setWriteQueueNums(requestHeader.getWriteQueueNums());
        topicConfig.setTopicFilterType(requestHeader.getTopicFilterTypeEnum());
        topicConfig.setPerm(requestHeader.getPerm());
        topicConfig.setTopicSysFlag(requestHeader.getTopicSysFlag() == null ? 0 : requestHeader.getTopicSysFlag());

        // 将topic元数据写入 topic元数据管理组件（注意：此处即创建topic），就是将topic元数据放入一个Map数据结构
        this.brokerController.getTopicConfigManager().updateTopicConfig(topicConfig);

        // 注册topic元数据信息到 Namesrv
        this.brokerController.registerIncrementBrokerData(topicConfig, this.brokerController.getTopicConfigManager().getDataVersion());

        response.setCode(ResponseCode.SUCCESS);
        return response;
    }

Topic元数据管理组件更新topic

org.apache.rocketmq.broker.topic.TopicConfigManager#updateTopicConfig

1. 更新元数据信息到内存元数据映射表；
2. 更新元数据信息版本号；
3. 将元数据信息持久化到磁盘文件；

   // 更新topic元数据
    public void updateTopicConfig(final TopicConfig topicConfig) {
        TopicConfig old = this.topicConfigTable.put(topicConfig.getTopicName(), topicConfig);
        if (old != null) {
            log.info("update topic config, old:[{}] new:[{}]", old, topicConfig);
        } else {
            log.info("create new topic [{}]", topicConfig);
        }
        // 更新数据版本号
        this.dataVersion.nextVersion();
        // 持久化元数据到磁盘
        this.persist();
    }

上报 topic元数据信息到所有 NameServer节点

org.apache.rocketmq.broker.BrokerController#registerIncrementBrokerData

public synchronized void registerIncrementBrokerData(TopicConfig topicConfig, DataVersion dataVersion) {
        TopicConfig registerTopicConfig = topicConfig;
        if (!PermName.isWriteable(this.getBrokerConfig().getBrokerPermission())
            || !PermName.isReadable(this.getBrokerConfig().getBrokerPermission())) {
            registerTopicConfig =
                new TopicConfig(topicConfig.getTopicName(), topicConfig.getReadQueueNums(), topicConfig.getWriteQueueNums(),
                    this.brokerConfig.getBrokerPermission());
        }

        ConcurrentMap<String, TopicConfig> topicConfigTable = new ConcurrentHashMap<String, TopicConfig>();
        topicConfigTable.put(topicConfig.getTopicName(), registerTopicConfig);
        TopicConfigSerializeWrapper topicConfigSerializeWrapper = new TopicConfigSerializeWrapper();
        topicConfigSerializeWrapper.setDataVersion(dataVersion);
        topicConfigSerializeWrapper.setTopicConfigTable(topicConfigTable);

        // 注册Broker信息到所有NameServer
        doRegisterBrokerAll(true, false, topicConfigSerializeWrapper);
    }

    // 注册topic元数据到所有nameServer节点
    private void doRegisterBrokerAll(boolean checkOrderConfig, boolean oneway,
        TopicConfigSerializeWrapper topicConfigWrapper) {
        List<RegisterBrokerResult> registerBrokerResultList = this.brokerOuterAPI.registerBrokerAll(
            this.brokerConfig.getBrokerClusterName(), // 集群名称
            this.getBrokerAddr(), // broker地址
            this.brokerConfig.getBrokerName(), // broker节点所在分组
            this.brokerConfig.getBrokerId(), // broker节点ID
            this.getHAServerAddr(), // HA服务地址
            topicConfigWrapper, // topic元数据
            this.filterServerManager.buildNewFilterServerList(), // filter服务地址列表
            oneway, // 是否是oneway单向发送
            this.brokerConfig.getRegisterBrokerTimeoutMills(), // 注册超时时间
            this.brokerConfig.isCompressedRegister()); // 是否压缩注册信息

        if (registerBrokerResultList.size() > 0) {
            RegisterBrokerResult registerBrokerResult = registerBrokerResultList.get(0);
            if (registerBrokerResult != null) {
                if (this.updateMasterHAServerAddrPeriodically && registerBrokerResult.getHaServerAddr() != null) {
                    this.messageStore.updateHaMasterAddress(registerBrokerResult.getHaServerAddr());
                }

                this.slaveSynchronize.setMasterAddr(registerBrokerResult.getMasterAddr());

                if (checkOrderConfig) {
                    this.getTopicConfigManager().updateOrderTopicConfig(registerBrokerResult.getKvTable());
                }
            }
        }
    }