RocketMq Topic创建和删除

开篇

• 这个系列主要用以分析mqadmin常见的比较核心的几个命令，主要包括订阅分组和topic的创建和删除、Topic的权限变更。
• 这篇文章主要是用来分析Topic的创建和删除。

创建Topic

Topic创建的核心步骤如下

• 1、mqadmin向broker发起创建Topic的命令。
• 2、broker生成Topic对应的topicConfig配置保存在broker的TopicConfigManager中。
• 3、broker向所有的namesrv上报topicConfig信息。
• 4、namesrv的RouteInfoManager的topicQueueTable保存topic的QueueData信息。
• 5、broker会通过定时任务定期向namesrv发送心跳信息更新topic配置。

updateTopic

usage: mqadmin updateTopic -b <arg> | -c <arg>  [-h] [-n <arg>] [-o <arg>] [-p <arg>] [-r <arg>] [-s <arg>] -t
       <arg> [-u <arg>] [-w <arg>]
 -b,--brokerAddr <arg>       create topic to which broker
 -c,--clusterName <arg>      create topic to which cluster
 -h,--help                   Print help
 -n,--namesrvAddr <arg>      Name server address list, eg: 192.168.0.1:9876;192.168.0.2:9876
 -o,--order <arg>            set topic's order(true|false)
 -p,--perm <arg>             set topic's permission(2|4|6), intro[2:W 4:R; 6:RW]
 -r,--readQueueNums <arg>    set read queue nums
 -s,--hasUnitSub <arg>       has unit sub (true|false)
 -t,--topic <arg>            topic name
 -u,--unit <arg>             is unit topic (true|false)
 -w,--writeQueueNums <arg>   set write queue nums

• 通过 --brokerAddr在指定的broker创建topic。
• 通过 --clusterName在整个集群创建topic。
• 通过 --namesrvAddr指定namesrv地址。
• 通过 --topic来指定topic名称。
• 通过 --perm来指定Topic的权限管理。

UpdateTopicSubCommand

public class UpdateTopicSubCommand implements SubCommand {

    @Override
    public void execute(final CommandLine commandLine, final Options options,
        RPCHook rpcHook) throws SubCommandException {
        DefaultMQAdminExt defaultMQAdminExt = new DefaultMQAdminExt(rpcHook);
        defaultMQAdminExt.setInstanceName(Long.toString(System.currentTimeMillis()));

        try {
            // 默认的topic的读写队列为8个
            TopicConfig topicConfig = new TopicConfig();
            topicConfig.setReadQueueNums(8);
            topicConfig.setWriteQueueNums(8);
            topicConfig.setTopicName(commandLine.getOptionValue('t').trim());

            // readQueueNums
            if (commandLine.hasOption('r')) {
                topicConfig.setReadQueueNums(Integer.parseInt(commandLine.getOptionValue('r').trim()));
            }

            // writeQueueNums
            if (commandLine.hasOption('w')) {
                topicConfig.setWriteQueueNums(Integer.parseInt(commandLine.getOptionValue('w').trim()));
            }

            // perm
            if (commandLine.hasOption('p')) {
                topicConfig.setPerm(Integer.parseInt(commandLine.getOptionValue('p').trim()));
            }

            boolean isUnit = false;
            if (commandLine.hasOption('u')) {
                isUnit = Boolean.parseBoolean(commandLine.getOptionValue('u').trim());
            }

            boolean isCenterSync = false;
            if (commandLine.hasOption('s')) {
                isCenterSync = Boolean.parseBoolean(commandLine.getOptionValue('s').trim());
            }

            int topicCenterSync = TopicSysFlag.buildSysFlag(isUnit, isCenterSync);
            topicConfig.setTopicSysFlag(topicCenterSync);

            boolean isOrder = false;
            if (commandLine.hasOption('o')) {
                isOrder = Boolean.parseBoolean(commandLine.getOptionValue('o').trim());
            }
            topicConfig.setOrder(isOrder);

            if (commandLine.hasOption('b')) {
                String addr = commandLine.getOptionValue('b').trim();

                defaultMQAdminExt.start();
                defaultMQAdminExt.createAndUpdateTopicConfig(addr, topicConfig);

                if (isOrder) {
                    String brokerName = CommandUtil.fetchBrokerNameByAddr(defaultMQAdminExt, addr);
                    String orderConf = brokerName + ":" + topicConfig.getWriteQueueNums();
                    defaultMQAdminExt.createOrUpdateOrderConf(topicConfig.getTopicName(), orderConf, false);
                    System.out.printf("%s", String.format("set broker orderConf. isOrder=%s, orderConf=[%s]",
                        isOrder, orderConf.toString()));
                }
                System.out.printf("create topic to %s success.%n", addr);
                System.out.printf("%s", topicConfig);
                return;

            } else if (commandLine.hasOption('c')) {
                String clusterName = commandLine.getOptionValue('c').trim();

                defaultMQAdminExt.start();

                Set<String> masterSet =
                    CommandUtil.fetchMasterAddrByClusterName(defaultMQAdminExt, clusterName);
                for (String addr : masterSet) {
                    defaultMQAdminExt.createAndUpdateTopicConfig(addr, topicConfig);
                    System.out.printf("create topic to %s success.%n", addr);
                }

                if (isOrder) {
                    Set<String> brokerNameSet =
                        CommandUtil.fetchBrokerNameByClusterName(defaultMQAdminExt, clusterName);
                    StringBuilder orderConf = new StringBuilder();
                    String splitor = "";
                    for (String s : brokerNameSet) {
                        orderConf.append(splitor).append(s).append(":")
                            .append(topicConfig.getWriteQueueNums());
                        splitor = ";";
                    }
                    defaultMQAdminExt.createOrUpdateOrderConf(topicConfig.getTopicName(),
                        orderConf.toString(), true);
                    System.out.printf("set cluster orderConf. isOrder=%s, orderConf=[%s]", isOrder, orderConf);
                }

                System.out.printf("%s", topicConfig);
                return;
            }

            ServerUtil.printCommandLineHelp("mqadmin " + this.commandName(), options);
        } catch (Exception e) {
            throw new SubCommandException(this.getClass().getSimpleName() + " command failed", e);
        } finally {
            defaultMQAdminExt.shutdown();
        }
    }
}

• Topic的默认的读写队列为8.
• 针对指定broker的场景，只在指定的broker机器创建Topic。
• 针对指定cluster的场景，获取集群下的所有broker并向全部的broker机器创建Topic。

mqadmin MQClientAPIImpl

public class MQClientAPIImpl {

    public void createTopic(final String addr, final String defaultTopic, final TopicConfig topicConfig,
        final long timeoutMillis)
        throws RemotingException, MQBrokerException, InterruptedException, MQClientException {
        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());

        RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.UPDATE_AND_CREATE_TOPIC, requestHeader);

        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());
    }
}

• 创建Topic的RequestCode为UPDATE_AND_CREATE_TOPIC。

broker AdminBrokerProcessor

public class AdminBrokerProcessor extends AsyncNettyRequestProcessor implements NettyRequestProcessor {

    private synchronized RemotingCommand updateAndCreateTopic(ChannelHandlerContext ctx,
        RemotingCommand request) throws RemotingCommandException {

        final RemotingCommand response = RemotingCommand.createResponseCommand(null);
        final CreateTopicRequestHeader requestHeader =
            (CreateTopicRequestHeader) request.decodeCommandCustomHeader(CreateTopicRequestHeader.class);

        if (requestHeader.getTopic().equals(this.brokerController.getBrokerConfig().getBrokerClusterName())) {
            String errorMsg = "the topic[" + requestHeader.getTopic() + "] is conflict with system reserved words.";
            log.warn(errorMsg);
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark(errorMsg);
            return response;
        }

        if (!TopicValidator.validateTopic(requestHeader.getTopic(), response)) {
            return response;
        }

        try {
            response.setCode(ResponseCode.SUCCESS);
            response.setOpaque(request.getOpaque());
            response.markResponseType();
            response.setRemark(null);
            ctx.writeAndFlush(response);
        } catch (Exception e) {
            log.error("Failed to produce a proper response", e);
        }
        // TopicConfig的创建配置
        TopicConfig topicConfig = new TopicConfig(requestHeader.getTopic());
        topicConfig.setReadQueueNums(requestHeader.getReadQueueNums());
        topicConfig.setWriteQueueNums(requestHeader.getWriteQueueNums());
        topicConfig.setTopicFilterType(requestHeader.getTopicFilterTypeEnum());
        topicConfig.setPerm(requestHeader.getPerm());
        topicConfig.setTopicSysFlag(requestHeader.getTopicSysFlag() == null ? 0 : requestHeader.getTopicSysFlag());
        // broker保存Topic的配置信息
        this.brokerController.getTopicConfigManager().updateTopicConfig(topicConfig);
        // broker负责向namesrv上报topic信息。
        this.brokerController.registerIncrementBrokerData(topicConfig, this.brokerController.getTopicConfigManager().getDataVersion());

        return null;
    }
}

• 创建TopicConfig对象并通过TopicConfigManager来进行保存。
• 通过brokerController#registerIncrementBrokerData来上报topic信息到namesrv。

broker TopicConfigManager

public class TopicConfigManager extends ConfigManager {

    private static final long LOCK_TIMEOUT_MILLIS = 3000;
    private transient final Lock lockTopicConfigTable = new ReentrantLock();

    private final ConcurrentMap<String, TopicConfig> topicConfigTable =
        new ConcurrentHashMap<String, TopicConfig>(1024);
    private final DataVersion dataVersion = new DataVersion();
    private final Set<String> systemTopicList = new HashSet<String>();
    private transient BrokerController brokerController;

    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);
        }

        this.dataVersion.nextVersion();

        this.persist();
    }
}

• 通过topicConfigTable来保存Topic和对应的TopicConfig。

broker BrokerController

public class BrokerController {

    public synchronized void registerIncrementBrokerData(TopicConfig topicConfig, DataVersion dataVersion) {

        TopicConfig registerTopicConfig = topicConfig;
        // 如果broker本身的存在不可读和不可写的权限，那么就以broker的读写权限为准
        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);
        // 将topic信息注册到namesrv的逻辑
        doRegisterBrokerAll(true, false, topicConfigSerializeWrapper);
    }


    private void doRegisterBrokerAll(boolean checkOrderConfig, boolean oneway,
        TopicConfigSerializeWrapper topicConfigWrapper) {
        // 向所有的namesrv发送topic的注册信息
        List<RegisterBrokerResult> registerBrokerResultList = this.brokerOuterAPI.registerBrokerAll(
            this.brokerConfig.getBrokerClusterName(),
            this.getBrokerAddr(),
            this.brokerConfig.getBrokerName(),
            this.brokerConfig.getBrokerId(),
            this.getHAServerAddr(),
            topicConfigWrapper,
            this.filterServerManager.buildNewFilterServerList(),
            oneway,
            this.brokerConfig.getRegisterBrokerTimeoutMills(),
            this.brokerConfig.isCompressedRegister());

        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());
                }
            }
        }
    }
}

• registerIncrementBrokerData首先会检查broker本身的读写权限重新生成新的topicConfigSerializeWrapper。
• 通过brokerOuterAPI#registerBrokerAll向namesrv注册最新的topic信息。

broker BrokerOuterAPI

public class BrokerOuterAPI {

    private RegisterBrokerResult registerBroker(
        final String namesrvAddr,
        final boolean oneway,
        final int timeoutMills,
        final RegisterBrokerRequestHeader requestHeader,
        final byte[] body
    ) throws RemotingCommandException, MQBrokerException, RemotingConnectException, RemotingSendRequestException, RemotingTimeoutException,
        InterruptedException {

        RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.REGISTER_BROKER, requestHeader);
        request.setBody(body);
        // oneway=false，这个分支不会执行
        if (oneway) {
            try {
                this.remotingClient.invokeOneway(namesrvAddr, request, timeoutMills);
            } catch (RemotingTooMuchRequestException e) {
                // Ignore
            }
            return null;
        }

        // 向namesrv上报
        RemotingCommand response = this.remotingClient.invokeSync(namesrvAddr, request, timeoutMills);
        // 处理上报结果并同步主从
        assert response != null;
        switch (response.getCode()) {
            case ResponseCode.SUCCESS: {
                RegisterBrokerResponseHeader responseHeader =
                    (RegisterBrokerResponseHeader) response.decodeCommandCustomHeader(RegisterBrokerResponseHeader.class);
                RegisterBrokerResult result = new RegisterBrokerResult();
                result.setMasterAddr(responseHeader.getMasterAddr());
                result.setHaServerAddr(responseHeader.getHaServerAddr());
                if (response.getBody() != null) {
                    result.setKvTable(KVTable.decode(response.getBody(), KVTable.class));
                }
                return result;
            }
            default:
                break;
        }

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

• 向namesrv注册topic的RequestCode为REGISTER_BROKER。
• broker向namesrv发起topic注册。

namesrv DefaultRequestProcessor

public class DefaultRequestProcessor implements NettyRequestProcessor {

    public RemotingCommand registerBrokerWithFilterServer(ChannelHandlerContext ctx, RemotingCommand request)
        throws RemotingCommandException {

        final RemotingCommand response = RemotingCommand.createResponseCommand(RegisterBrokerResponseHeader.class);
        final RegisterBrokerResponseHeader responseHeader = (RegisterBrokerResponseHeader) response.readCustomHeader();
        final RegisterBrokerRequestHeader requestHeader =
            (RegisterBrokerRequestHeader) request.decodeCommandCustomHeader(RegisterBrokerRequestHeader.class);

        if (!checksum(ctx, request, requestHeader)) {
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("crc32 not match");
            return response;
        }

        RegisterBrokerBody registerBrokerBody = new RegisterBrokerBody();

        if (request.getBody() != null) {
            try {
                registerBrokerBody = RegisterBrokerBody.decode(request.getBody(), requestHeader.isCompressed());
            } catch (Exception e) {
                throw new RemotingCommandException("Failed to decode RegisterBrokerBody", e);
            }
        } else {
            registerBrokerBody.getTopicConfigSerializeWrapper().getDataVersion().setCounter(new AtomicLong(0));
            registerBrokerBody.getTopicConfigSerializeWrapper().getDataVersion().setTimestamp(0);
        }
        // namesrv同时注册broker信息和TopicConfig信息
        RegisterBrokerResult result = this.namesrvController.getRouteInfoManager().registerBroker(
            requestHeader.getClusterName(),
            requestHeader.getBrokerAddr(),
            requestHeader.getBrokerName(),
            requestHeader.getBrokerId(),
            requestHeader.getHaServerAddr(),
            registerBrokerBody.getTopicConfigSerializeWrapper(),
            registerBrokerBody.getFilterServerList(),
            ctx.channel());

        responseHeader.setHaServerAddr(result.getHaServerAddr());
        responseHeader.setMasterAddr(result.getMasterAddr());

        byte[] jsonValue = this.namesrvController.getKvConfigManager().getKVListByNamespace(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG);
        response.setBody(jsonValue);

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

• getRouteInfoManager().registerBroker()负责向namesrv注册broker信息。

namesrv RouteInfoManager

public class RouteInfoManager {

    private final static long BROKER_CHANNEL_EXPIRED_TIME = 1000 * 60 * 2;
    private final ReadWriteLock lock = new ReentrantReadWriteLock();
    private final HashMap<String/* topic */, List<QueueData>> topicQueueTable;
    private final HashMap<String/* brokerName */, BrokerData> brokerAddrTable;
    private final HashMap<String/* clusterName */, Set<String/* brokerName */>> clusterAddrTable;
    private final HashMap<String/* brokerAddr */, BrokerLiveInfo> brokerLiveTable;
    private final HashMap<String/* brokerAddr */, List<String>/* Filter Server */> filterServerTable;

    public RouteInfoManager() {
        this.topicQueueTable = new HashMap<String, List<QueueData>>(1024);
        this.brokerAddrTable = new HashMap<String, BrokerData>(128);
        this.clusterAddrTable = new HashMap<String, Set<String>>(32);
        this.brokerLiveTable = new HashMap<String, BrokerLiveInfo>(256);
        this.filterServerTable = new HashMap<String, List<String>>(256);
    }

    public RegisterBrokerResult registerBroker(
        final String clusterName,
        final String brokerAddr,
        final String brokerName,
        final long brokerId,
        final String haServerAddr,
        final TopicConfigSerializeWrapper topicConfigWrapper,
        final List<String> filterServerList,
        final Channel channel) {
        RegisterBrokerResult result = new RegisterBrokerResult();

        try {
            try {
                this.lock.writeLock().lockInterruptibly();

                Set<String> brokerNames = this.clusterAddrTable.get(clusterName);
                if (null == brokerNames) {
                    brokerNames = new HashSet<String>();
                    this.clusterAddrTable.put(clusterName, brokerNames);
                }
                brokerNames.add(brokerName);

                boolean registerFirst = false;

                BrokerData brokerData = this.brokerAddrTable.get(brokerName);
                if (null == brokerData) {
                    registerFirst = true;
                    brokerData = new BrokerData(clusterName, brokerName, new HashMap<Long, String>());
                    this.brokerAddrTable.put(brokerName, brokerData);
                }
                Map<Long, String> brokerAddrsMap = brokerData.getBrokerAddrs();
                //Switch slave to master: first remove <1, IP:PORT> in namesrv, then add <0, IP:PORT>
                //The same IP:PORT must only have one record in brokerAddrTable
                Iterator<Entry<Long, String>> it = brokerAddrsMap.entrySet().iterator();
                while (it.hasNext()) {
                    Entry<Long, String> item = it.next();
                    if (null != brokerAddr && brokerAddr.equals(item.getValue()) && brokerId != item.getKey()) {
                        it.remove();
                    }
                }

                String oldAddr = brokerData.getBrokerAddrs().put(brokerId, brokerAddr);
                registerFirst = registerFirst || (null == oldAddr);

                // 保存topicConfig的信息
                if (null != topicConfigWrapper
                    && MixAll.MASTER_ID == brokerId) {
                    if (this.isBrokerTopicConfigChanged(brokerAddr, topicConfigWrapper.getDataVersion())
                        || registerFirst) {
                        ConcurrentMap<String, TopicConfig> tcTable =
                            topicConfigWrapper.getTopicConfigTable();
                        if (tcTable != null) {
                            for (Map.Entry<String, TopicConfig> entry : tcTable.entrySet()) {
                                this.createAndUpdateQueueData(brokerName, entry.getValue());
                            }
                        }
                    }
                }

                BrokerLiveInfo prevBrokerLiveInfo = this.brokerLiveTable.put(brokerAddr,
                    new BrokerLiveInfo(
                        System.currentTimeMillis(),
                        topicConfigWrapper.getDataVersion(),
                        channel,
                        haServerAddr));
                if (null == prevBrokerLiveInfo) {
                    log.info("new broker registered, {} HAServer: {}", brokerAddr, haServerAddr);
                }

                if (filterServerList != null) {
                    if (filterServerList.isEmpty()) {
                        this.filterServerTable.remove(brokerAddr);
                    } else {
                        this.filterServerTable.put(brokerAddr, filterServerList);
                    }
                }

                if (MixAll.MASTER_ID != brokerId) {
                    String masterAddr = brokerData.getBrokerAddrs().get(MixAll.MASTER_ID);
                    if (masterAddr != null) {
                        BrokerLiveInfo brokerLiveInfo = this.brokerLiveTable.get(masterAddr);
                        if (brokerLiveInfo != null) {
                            result.setHaServerAddr(brokerLiveInfo.getHaServerAddr());
                            result.setMasterAddr(masterAddr);
                        }
                    }
                }
            } finally {
                this.lock.writeLock().unlock();
            }
        } catch (Exception e) {
            log.error("registerBroker Exception", e);
        }

        return result;
    }
}

• RouteInfoManager是namesrv的核心数据管理中心，broker上报Topic的过程中会同时更新broker的保活信息等。
• 核心的createAndUpdateQueueData负责注册topic配置信息。

namesrv createAndUpdateQueueData

public class RouteInfoManager {

    private void createAndUpdateQueueData(final String brokerName, final TopicConfig topicConfig) {

        QueueData queueData = new QueueData();
        queueData.setBrokerName(brokerName);
        queueData.setWriteQueueNums(topicConfig.getWriteQueueNums());
        queueData.setReadQueueNums(topicConfig.getReadQueueNums());
        queueData.setPerm(topicConfig.getPerm());
        queueData.setTopicSynFlag(topicConfig.getTopicSysFlag());

        List<QueueData> queueDataList = this.topicQueueTable.get(topicConfig.getTopicName());
        if (null == queueDataList) {
            queueDataList = new LinkedList<QueueData>();
            queueDataList.add(queueData);
            this.topicQueueTable.put(topicConfig.getTopicName(), queueDataList);
            log.info("new topic registered, {} {}", topicConfig.getTopicName(), queueData);
        } else {
            boolean addNewOne = true;

            Iterator<QueueData> it = queueDataList.iterator();
            while (it.hasNext()) {
                QueueData qd = it.next();
                if (qd.getBrokerName().equals(brokerName)) {
                    if (qd.equals(queueData)) {
                        addNewOne = false;
                    } else {
                        log.info("topic changed, {} OLD: {} NEW: {}", topicConfig.getTopicName(), qd,
                            queueData);
                        it.remove();
                    }
                }
            }

            if (addNewOne) {
                queueDataList.add(queueData);
            }
        }
    }
}

• 负责创建QueueData并保存到topicQueueTable当中。
• createAndUpdateQueueData会处理所有broker的上报，所以在处理QueueData过程中需要判断brokerName以处理对应的broker的QueueData。

定时上报 BrokerController

public class BrokerController {

    public void start() throws Exception {

        this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

            @Override
            public void run() {
                try {
                    BrokerController.this.registerBrokerAll(true, false, brokerConfig.isForceRegister());
                } catch (Throwable e) {
                    log.error("registerBrokerAll Exception", e);
                }
            }
        }, 1000 * 10, Math.max(10000, Math.min(brokerConfig.getRegisterNameServerPeriod(), 60000)), TimeUnit.MILLISECONDS);
}

• broker会定时向namesrv上报broker的信息并且包括topic的注册信息。

删除Topic

删除Topic的核心逻辑如下

• 1、mqadmin负责通知所有的broker删除topic对应的配置和消息文件。
• 2、mqadmin负责通知所有的namesrv删除topic对应的配置。

deleteTopic

usage: mqadmin deleteTopic -c <arg> [-h] [-n <arg>] -t <arg>
 -c,--clusterName <arg>   delete topic from which cluster
 -h,--help                Print help
 -n,--namesrvAddr <arg>   Name server address list, eg: 192.168.0.1:9876;192.168.0.2:9876
 -t,--topic <arg>         topic name

• --topic指定待删除的topic信息。
• --clusterName指定待删除Topic所在的集群信息。

mqadmin DeleteTopicSubCommand

public class DeleteTopicSubCommand implements SubCommand {

    public static void deleteTopic(final DefaultMQAdminExt adminExt,
        final String clusterName,
        final String topic
    ) throws InterruptedException, MQBrokerException, RemotingException, MQClientException {

        Set<String> brokerAddressSet = CommandUtil.fetchMasterAndSlaveAddrByClusterName(adminExt, clusterName);
        adminExt.deleteTopicInBroker(brokerAddressSet, topic);
        System.out.printf("delete topic [%s] from cluster [%s] success.%n", topic, clusterName);

        Set<String> nameServerSet = null;
        if (adminExt.getNamesrvAddr() != null) {
            String[] ns = adminExt.getNamesrvAddr().trim().split(";");
            nameServerSet = new HashSet(Arrays.asList(ns));
        }

        adminExt.deleteTopicInNameServer(nameServerSet, topic);
        System.out.printf("delete topic [%s] from NameServer success.%n", topic);
    }

    @Override
    public void execute(CommandLine commandLine, Options options, RPCHook rpcHook) throws SubCommandException {
        DefaultMQAdminExt adminExt = new DefaultMQAdminExt(rpcHook);
        adminExt.setInstanceName(Long.toString(System.currentTimeMillis()));
        try {
            String topic = commandLine.getOptionValue('t').trim();

            if (commandLine.hasOption('c')) {
                String clusterName = commandLine.getOptionValue('c').trim();

                adminExt.start();
                deleteTopic(adminExt, clusterName, topic);
                return;
            }

            ServerUtil.printCommandLineHelp("mqadmin " + this.commandName(), options);
        } catch (Exception e) {
            throw new SubCommandException(this.getClass().getSimpleName() + " command failed", e);
        } finally {
            adminExt.shutdown();
        }
    }
}

• deleteTopicInBroker负责当前集群的所有broker上的Topic信息。
• deleteTopicInNameServer负责删除namesrv中的topic信息

mqadmin DefaultMQAdminExtImpl

public class DefaultMQAdminExtImpl implements MQAdminExt, MQAdminExtInner {

    public void deleteTopicInBroker(Set<String> addrs,
        String topic) throws RemotingException, MQBrokerException, InterruptedException,
        MQClientException {
        for (String addr : addrs) {
            this.mqClientInstance.getMQClientAPIImpl().deleteTopicInBroker(addr, topic, timeoutMillis);
        }
    }
}

• 遍历所有broker依次执行deleteTopicInBroker操作。

mqadmin MQClientAPIImpl

public class MQClientAPIImpl {

    public void deleteTopicInBroker(final String addr, final String topic, final long timeoutMillis)
        throws RemotingException, MQBrokerException, InterruptedException, MQClientException {
        DeleteTopicRequestHeader requestHeader = new DeleteTopicRequestHeader();
        requestHeader.setTopic(topic);
        RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.DELETE_TOPIC_IN_BROKER, requestHeader);

        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());
    }
}

• deleteTopicInBroker的RequestCode为DELETE_TOPIC_IN_BROKER。

broker AdminBrokerProcessor

public class AdminBrokerProcessor implements NettyRequestProcessor {

    private synchronized RemotingCommand deleteTopic(ChannelHandlerContext ctx,
        RemotingCommand request) throws RemotingCommandException {
        final RemotingCommand response = RemotingCommand.createResponseCommand(null);
        DeleteTopicRequestHeader requestHeader =
            (DeleteTopicRequestHeader) request.decodeCommandCustomHeader(DeleteTopicRequestHeader.class);

        log.info("deleteTopic called by {}", RemotingHelper.parseChannelRemoteAddr(ctx.channel()));
        // 删除配置信息
        this.brokerController.getTopicConfigManager().deleteTopicConfig(requestHeader.getTopic());
        // 删除消息存储文件
        this.brokerController.getMessageStore()
            .cleanUnusedTopic(this.brokerController.getTopicConfigManager().getTopicConfigTable().keySet());

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

public class TopicConfigManager extends ConfigManager {

    public void deleteTopicConfig(final String topic) {
        // 从topicConfigTable中删除topic的配置信息
        TopicConfig old = this.topicConfigTable.remove(topic);
        if (old != null) {
            log.info("delete topic config OK, topic: {}", old);
            this.dataVersion.nextVersion();
            this.persist();
        } else {
            log.warn("delete topic config failed, topic: {} not exists", topic);
        }
    }

• deleteTopic操作包括删除broker上topic的配置信息和topic对应的消息存储文件。

mqadmin DefaultMQAdminExtImpl

public class DefaultMQAdminExtImpl implements MQAdminExt, MQAdminExtInner {

    @Override
    public void deleteTopicInNameServer(Set<String> addrs,
        String topic) throws RemotingException, MQBrokerException, InterruptedException,
        MQClientException {
        if (addrs == null) {
            String ns = this.mqClientInstance.getMQClientAPIImpl().fetchNameServerAddr();
            addrs = new HashSet(Arrays.asList(ns.split(";")));
        }
        for (String addr : addrs) {
            this.mqClientInstance.getMQClientAPIImpl().deleteTopicInNameServer(addr, topic, timeoutMillis);
        }
    }
}


public class MQClientAPIImpl {

    public void deleteTopicInNameServer(final String addr, final String topic, final long timeoutMillis)
        throws RemotingException, MQBrokerException, InterruptedException, MQClientException {
        DeleteTopicRequestHeader requestHeader = new DeleteTopicRequestHeader();
        requestHeader.setTopic(topic);
        RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.DELETE_TOPIC_IN_NAMESRV, requestHeader);

        RemotingCommand response = this.remotingClient.invokeSync(addr, request, timeoutMillis);
        assert response != null;
        switch (response.getCode()) {
            case ResponseCode.SUCCESS: {
                return;
            }
            default:
                break;
        }

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

• 遍历所有的namesrv并依次执行topic的删除。
• requestCode为DELETE_TOPIC_IN_NAMESRV。

namesrv DefaultRequestProcessor

public class DefaultRequestProcessor implements NettyRequestProcessor {

    private RemotingCommand deleteTopicInNamesrv(ChannelHandlerContext ctx,
        RemotingCommand request) throws RemotingCommandException {
        final RemotingCommand response = RemotingCommand.createResponseCommand(null);
        final DeleteTopicInNamesrvRequestHeader requestHeader =
            (DeleteTopicInNamesrvRequestHeader) request.decodeCommandCustomHeader(DeleteTopicInNamesrvRequestHeader.class);

        this.namesrvController.getRouteInfoManager().deleteTopic(requestHeader.getTopic());

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


public class RouteInfoManager {

    public void deleteTopic(final String topic) {
        try {
            try {
                this.lock.writeLock().lockInterruptibly();
                this.topicQueueTable.remove(topic);
            } finally {
                this.lock.writeLock().unlock();
            }
        } catch (Exception e) {
            log.error("deleteTopic Exception", e);
        }
    }
}

• namesrv的topic删除负责从RouteInfoManager移除topic对应的QueueData。