RocketMQ：NameServer路由管理源码分析
文章目录
-
- NameServer路由管理
-
- 1.前言
- 2.路由元信息
- 3.路由注册
-
- 3.1Broker路由注册
- 3.2NameServer处理路由注册
- 3.3路由删除
-
- 3.3.1Broker异常关闭
- 3.3.2Broker正常关闭
- 3.4路由发现
- 3.5总结
NameServer路由管理
1.前言
NameServer主要作用是为消息消费者和消息生产者提供关于主题Topic的路由信息，那么NameServer需要存储路由的基本信息，还要管理Broker节点，包括路由注册、路由删除等。
2.路由元信息
路由元信息主要由RouteInfoManager来进行管理，这个类在上一篇文章中已经介绍过，这里再做一下简单的介绍。
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;
BROKER_CHANNEL_EXPIRED_TIME：NameServer与Broker空闲连接时长，在2minNameServer之内没有收到Broker的心跳包，则NameServer会关闭与该Broker的连接并删除Broker的路由信息。
lock：读写锁，用来保护以下用于存储关键信息的非线程安全容器HashMap。
topicQueueTable：Topic消息队列路由信息，消息发送时根据路由表进行负载均衡
brokerAddrTable：Broker基础信息，包括brokerName、所属集群名称、主备Broker地址
clusterAddrTable：Broker集群信息，存储集群中所有Broker名称
brokerLiveTable：Broker状态信息，NameServer每次收到心跳包会对该表进行信息维护。
filterServerTable：Broker上的FilterServer列表，用于类模式消息过滤。
RocketMQ基于定于发布机制，一个Topic拥有多个消息队列，一个Broker为每一个主题创建4个读队列和4个写队列。多个Broker组成一个集群，集群由相同的多台Broker组成Master-Slave架构，brokerId为0代表Master，大于0为Slave。BrokerLiveInfo中的lastUpdateTimestamp存储上次收到Broker心跳包的时间。
3.路由注册
以下是路由注册的时序图：
RocketMQ的路由注册功能是通过Broker与NameServer的心跳机制实现的。Broker启动时向NameServer集群发送心跳信息，每隔30s向集群所有NameServer发送心跳包，NameServer接收到之后会对brokerLiveTable中的BrokerLiveInfo的lastUpdateTimeStamp属性值进行更新。此外NameServer会每隔10s扫描brokerLiveTable，如果检测到有Broker连续120s没有发送心跳包，则NameServer将移除Broker的路由信息同时关闭Socket连接。
源码
3.1Broker路由注册
BrokerController#start
//...进行检查
if (!messageStoreConfig.isEnableDLegerCommitLog()) {
startProcessorByHa(messageStoreConfig.getBrokerRole());
handleSlaveSynchronize(messageStoreConfig.getBrokerRole());
//注册Broker信息
this.registerBrokerAll(true, false, true);
}
//创建定时任务线程池
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
//每隔三十秒注册Broker信息
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);
if (this.brokerStatsManager != null) {
this.brokerStatsManager.start();
}
if (this.brokerFastFailure != null) {
this.brokerFastFailure.start();
}
}
BrokerController#registerBrokerAll
if (forceRegister || needRegister(this.brokerConfig.getBrokerClusterName(),
this.getBrokerAddr(),
this.brokerConfig.getBrokerName(),
this.brokerConfig.getBrokerId(),
this.brokerConfig.getRegisterBrokerTimeoutMills())) {
//开始注册
doRegisterBrokerAll(checkOrderConfig, oneway, topicConfigWrapper);
}
BrokerController#doRegisterBrokerAll
//进入brokerOuterAPI#registerBrokerAll
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());
BrokerOuterAPI#registerBrokerAll
final List<RegisterBrokerResult> registerBrokerResultList = new CopyOnWriteArrayList<>();
//获取nameServer地址信息
List<String> nameServerAddressList = this.remotingClient.getNameServerAddressList();
if (nameServerAddressList != null && nameServerAddressList.size() > 0) {
//进行请求头的封装
final RegisterBrokerRequestHeader requestHeader = new RegisterBrokerRequestHeader();
requestHeader.setBrokerAddr(brokerAddr);
requestHeader.setBrokerId(brokerId);
requestHeader.setBrokerName(brokerName);
requestHeader.setClusterName(clusterName);
requestHeader.setHaServerAddr(haServerAddr);
requestHeader.setCompressed(compressed);
//封装注册请求体
RegisterBrokerBody requestBody = new RegisterBrokerBody();
requestBody.setTopicConfigSerializeWrapper(topicConfigWrapper);
requestBody.setFilterServerList(filterServerList);
final byte[] body = requestBody.encode(compressed);
final int bodyCrc32 = UtilAll.crc32(body);
requestHeader.setBodyCrc32(bodyCrc32);
final CountDownLatch countDownLatch = new CountDownLatch(nameServerAddressList.size());
//遍历nameServer地址 ---> 分别向各个nameServer注册Broker
for (final String namesrvAddr : nameServerAddressList) {
brokerOuterExecutor.execute(new Runnable() {
@Override
public void run() {
try {
//向nameServer注册Broker并返回注册结果
RegisterBrokerResult result = registerBroker(namesrvAddr, oneway, timeoutMills, requestHeader, body);
if (result != null) {
registerBrokerResultList.add(result);
}
log.info("register broker[{}]to name server {} OK", brokerId, namesrvAddr);
} catch (Exception e) {
log.warn("registerBroker Exception, {}", namesrvAddr, e);
} finally {
countDownLatch.countDown();
}
}
});
}
try {
countDownLatch.await(timeoutMills, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
}
}
return registerBrokerResultList;
BrokerOuterAPI#registerBroker
//如果是oneway发送 无需关注返回结果 直接返回null
if (oneway) {
try {
this.remotingClient.invokeOneway(namesrvAddr, request, timeoutMills);
} catch (RemotingTooMuchRequestException e) {
// Ignore
log.error("RemotingTooMuchRequestException!!!");
}
return null;
}
//返回远程调用的响应结果
RemotingCommand response = this.remotingClient.invokeSync(namesrvAddr, request, timeoutMills);
3.2NameServer处理路由注册
以下是NameServer处理路由注册的时序图：
请求发送至NameServer，会由默认的网络处理解析类DefaultRequestProcessor进行处理解析，如果请求类型是REGISTER_BROKER则会将请求转发至RouteInfoManager进行路由的注册。
源码
DefaultRequestProcessor#processRequest
switch (request.getCode()) {
case RequestCode.REGISTER_BROKER:
Version brokerVersion = MQVersion.value2Version(request.getVersion());
//高版本进入这个分支
if (brokerVersion.ordinal() >= MQVersion.Version.V3_0_11.ordinal()) {
return this.registerBrokerWithFilterServer(ctx, request);
} else {
return this.registerBroker(ctx, request);
}
}
DefaultRequestProcessor#registerBrokerWithFilterServer
//转发到NameServerController中的RouteInfoManager进行路由注册
RegisterBrokerResult result = this.namesrvController.getRouteInfoManager().registerBroker(
requestHeader.getClusterName(),
requestHeader.getBrokerAddr(),
requestHeader.getBrokerName(),
requestHeader.getBrokerId(),
requestHeader.getHaServerAddr(),
registerBrokerBody.getTopicConfigSerializeWrapper(),
registerBrokerBody.getFilterServerList(),
ctx.channel());
RouteInfoManager#registerBroker
//加入写锁-保护HashTable线程安全
this.lock.writeLock().lockInterruptibly();
//维护clusterAddrTable
Set<String> brokerNames = this.clusterAddrTable.get(clusterName);
if (null == brokerNames) {
brokerNames = new HashSet<String>();
this.clusterAddrTable.put(clusterName, brokerNames);
}
brokerNames.add(brokerName);
//维护brokerAddrTable
//是否是第一次注册 默认为false
boolean registerFirst = false;
BrokerData brokerData = this.brokerAddrTable.get(brokerName);
//如果在brokerAddrTable没有该Broker信息
if (null == brokerData) {
//设置为第一次注册
registerFirst = true;
//创建对应的BrokerData信息
brokerData = new BrokerData(clusterName, brokerName, new HashMap<Long, String>());
this.brokerAddrTable.put(brokerName, brokerData);
}
//不是第一次注册-对Broker信息进行更新
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);
//维护topicQueueTable
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()) {
//具体细节在这个方法中
this.createAndUpdateQueueData(brokerName, entry.getValue());
}
}
}
}
//维护brokerLiveTable
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);
}
//维护filterServerTable
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);
}
}
}
RouteInfoManager#createAndUpdateQueueData
//创建并封装新的队列信息
QueueData queueData = new QueueData();
//Broker名称
queueData.setBrokerName(brokerName);
//读写队列个数
queueData.setWriteQueueNums(topicConfig.getWriteQueueNums());
queueData.setReadQueueNums(topicConfig.getReadQueueNums());
//操作权限
queueData.setPerm(topicConfig.getPerm());
//同步复制还是异步复制的标识
queueData.setTopicSysFlag(topicConfig.getTopicSysFlag());
//根据Topic从topicQueueTable中获取队列集合
List<QueueData> queueDataList = this.topicQueueTable.get(topicConfig.getTopicName());
//如果没有获取到
if (null == queueDataList) {
//创建并将新的queueData添加到集合中
queueDataList = new LinkedList<QueueData>();
queueDataList.add(queueData);
//放入topicQueueTable
this.topicQueueTable.put(topicConfig.getTopicName(), queueDataList);
log.info("new topic registered, {} {}", topicConfig.getTopicName(), queueData);
}
//queueDataList不为空
else {
boolean addNewOne = true;
Iterator<QueueData> it = queueDataList.iterator();
//对该主题已有队列信息进行遍历
while (it.hasNext()) {
QueueData qd = it.next();
//如果找到相同主题
if (qd.getBrokerName().equals(brokerName)) {
//已经存在
if (qd.equals(queueData)) {
addNewOne = false;
} else {
//进行更改-先删除后新增
log.info("topic changed, {} OLD: {} NEW: {}", topicConfig.getTopicName(), qd,
queueData);
it.remove();
}
}
}
//添加一个新的队列信息
if (addNewOne) {
queueDataList.add(queueData);
}
}
3.3路由删除
NameServer会每隔10s扫描brokerLiveTable状态表，如果BrokerLive的lastUpdateTimestamp的时间戳距当前时间超过120s，则认为Broker失效，移除该Broker，关闭与Broker连接，同时更新topicQueueTable、brokerAddrTable、brokerLiveTable、filterServerTable。
删除路由信息的两个触发条件：
- NameServer定期扫描brokerLiveTable检测上次心跳包发送时间与当前系统的时间差，如果时间超过
120s，则需要移除该Broker路由信息 - Broker正常关闭，执行
unregisterBroker
3.3.1Broker异常关闭
NamesrvController#initialize
//定时任务线程池--->每隔十秒扫描活跃状态异常的Broker信息
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
/**
* 对Not Active Broker 进行扫描
*/
@Override
public void run() {
//在routeInfoManager中进行路由删除
NamesrvController.this.routeInfoManager.scanNotActiveBroker();
}
}, 5, 10, TimeUnit.SECONDS);
RouteInfoManager#scanNotActiveBroker
//遍历brokerLiveTable 查看是否有broker状态长时间没有更新
Iterator<Entry<String, BrokerLiveInfo>> it = this.brokerLiveTable.entrySet().iterator();
//遍历brokerLiveTable
while (it.hasNext()) {
Entry<String, BrokerLiveInfo> next = it.next();
long last = next.getValue().getLastUpdateTimestamp();
//如果收到心跳包的时间间距超过120s
if ((last + BROKER_CHANNEL_EXPIRED_TIME) < System.currentTimeMillis()) {
//关闭连接
RemotingUtil.closeChannel(next.getValue().getChannel());
//移除broker
it.remove();
log.warn("The broker channel expired, {} {}ms", next.getKey(), BROKER_CHANNEL_EXPIRED_TIME);
//维护路由表
this.onChannelDestroy(next.getKey(), next.getValue().getChannel());
}
}
RouteInfoManager#onChannelDestroy
//待删除的BrokerAddress
String brokerAddrFound = null;
if (channel != null) {
try {
try {
//加入读锁
this.lock.readLock().lockInterruptibly();
Iterator<Entry<String, BrokerLiveInfo>> itBrokerLiveTable =
this.brokerLiveTable.entrySet().iterator();
//遍历查找待删除的Broker
while (itBrokerLiveTable.hasNext()) {
Entry<String, BrokerLiveInfo> entry = itBrokerLiveTable.next();
if (entry.getValue().getChannel() == channel) {
brokerAddrFound = entry.getKey();
break;
}
}
} finally {
//释放锁
this.lock.readLock().unlock();
}
} catch (Exception e) {
log.error("onChannelDestroy Exception", e);
}
}
//加入写锁
//根据brokerAddrFound从brokerLiveTable和filterServerTable移除对应的Broker信息
this.lock.writeLock().lockInterruptibly();
this.brokerLiveTable.remove(brokerAddrFound);
this.filterServerTable.remove(brokerAddrFound);
//维护brokerAddrTable
String brokerNameFound = null;
boolean removeBrokerName = false;
Iterator<Entry<String, BrokerData>> itBrokerAddrTable =
this.brokerAddrTable.entrySet().iterator();
//遍历brokerAddrTable
while (itBrokerAddrTable.hasNext() && (null == brokerNameFound)) {
BrokerData brokerData = itBrokerAddrTable.next().getValue();
//遍历brokerAddress
Iterator<Entry<Long, String>> it = brokerData.getBrokerAddrs().entrySet().iterator();
while (it.hasNext()) {
Entry<Long, String> entry = it.next();
Long brokerId = entry.getKey();
String brokerAddr = entry.getValue();
//遍历到匹配的broker
if (brokerAddr.equals(brokerAddrFound)) {
brokerNameFound = brokerData.getBrokerName();
//根据broker地址移除broker
it.remove();
log.info("remove brokerAddr[{}, {}] from brokerAddrTable, because channel destroyed",
brokerId, brokerAddr);
break;
}
}
//如果当前BrokerData中的Broker列表为空
if (brokerData.getBrokerAddrs().isEmpty()) {
removeBrokerName = true;
//从BrokerAddrTable移除该BrokerData
itBrokerAddrTable.remove();
log.info("remove brokerName[{}] from brokerAddrTable, because channel destroyed",
brokerData.getBrokerName());
}
}
//维护clusterAddrTable
if (brokerNameFound != null && removeBrokerName) {
Iterator<Entry<String, Set<String>>> it = this.clusterAddrTable.entrySet().iterator();
//遍历clusterAddrTable
while (it.hasNext()) {
Entry<String, Set<String>> entry = it.next();
String clusterName = entry.getKey();
Set<String> brokerNames = entry.getValue();
//根据brokerName删除cluster集群中的broker并返回是否删除成功
boolean removed = brokerNames.remove(brokerNameFound);
if (removed) {
log.info("remove brokerName[{}], clusterName[{}] from clusterAddrTable, because channel destroyed",
brokerNameFound, clusterName);
//如果cluster已经不包含任何broker则移除该集群
if (brokerNames.isEmpty()) {
log.info("remove the clusterName[{}] from clusterAddrTable, because channel destroyed and no broker in this cluster",
clusterName);
it.remove();
}
break;
}
}
}
//维护TopicQueueTable
if (removeBrokerName) {
Iterator<Entry<String, List<QueueData>>> itTopicQueueTable =
this.topicQueueTable.entrySet().iterator();
//遍历TopicQueueTable
while (itTopicQueueTable.hasNext()) {
Entry<String, List<QueueData>> entry = itTopicQueueTable.next();
//主题
String topic = entry.getKey();
//主题对应的Broker信息
List<QueueData> queueDataList = entry.getValue();
Iterator<QueueData> itQueueData = queueDataList.iterator();
//遍历Broker
while (itQueueData.hasNext()) {
QueueData queueData = itQueueData.next();
//通过brokerNameFound在queueData中查找对应的Broker信息
if (queueData.getBrokerName().equals(brokerNameFound)) {
//移除该Broker
itQueueData.remove();
log.info("remove topic[{} {}], from topicQueueTable, because channel destroyed",
topic, queueData);
}
}
//如果当前主题已经没有任何Broker，则移除该主题Topic
if (queueDataList.isEmpty()) {
itTopicQueueTable.remove();
log.info("remove topic[{}] all queue, from topicQueueTable, because channel destroyed",
topic);
}
}
}
//释放写锁
finally {
this.lock.writeLock().unlock();
}
3.3.2Broker正常关闭
关闭入口-BrokerController
//BrokerController#shutdown
this.unregisterBrokerAll();
//BrokerController#unregisterBrokerAll
this.brokerOuterAPI.unregisterBrokerAll(
this.brokerConfig.getBrokerClusterName(),
this.getBrokerAddr(),
this.brokerConfig.getBrokerName(),
this.brokerConfig.getBrokerId());
BrokerOuterAPI#unregisterBrokerAll
//获取NameServerAddress列表
List<String> nameServerAddressList = this.remotingClient.getNameServerAddressList();
if (nameServerAddressList != null) {
//遍历NameServer
for (String namesrvAddr : nameServerAddressList) {
try {
//注销指定Broker
this.unregisterBroker(namesrvAddr, clusterName, brokerAddr, brokerName, brokerId);
log.info("unregisterBroker OK, NamesrvAddr: {}", namesrvAddr);
} catch (Exception e) {
log.warn("unregisterBroker Exception, {}", namesrvAddr, e);
}
}
}
BrokerOuterAPI#unregisterBroker
//封装注销Broker请求头
UnRegisterBrokerRequestHeader requestHeader = new UnRegisterBrokerRequestHeader();
requestHeader.setBrokerAddr(brokerAddr);
requestHeader.setBrokerId(brokerId);
requestHeader.setBrokerName(brokerName);
requestHeader.setClusterName(clusterName);
//封装注销请求
RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.UNREGISTER_BROKER, requestHeader);
//远程调用并发送请求-返回响应结果
RemotingCommand response = this.remotingClient.invokeSync(namesrvAddr, request, 3000);
assert response != null;
switch (response.getCode()) {
case ResponseCode.SUCCESS: {
return;
}
default:
break;
}
throw new MQBrokerException(response.getCode(), response.getRemark(), brokerAddr);
忽略Netty远程调用过程
DefaultRequestProcess#processRequest
//根据请求状态码-进行不同的处理
switch (request.getCode()) {
case RequestCode.UNREGISTER_BROKER:
return this.unregisterBroker(ctx, request);
}
DefaultRequestProcess#unregisterBroker
final RemotingCommand response = RemotingCommand.createResponseCommand(null);
//解码注销Broker的请求头
final UnRegisterBrokerRequestHeader requestHeader =
(UnRegisterBrokerRequestHeader) request.decodeCommandCustomHeader(UnRegisterBrokerRequestHeader.class);
//转发至RouteInfoManager注销Broker
this.namesrvController.getRouteInfoManager().unregisterBroker(
requestHeader.getClusterName(),
requestHeader.getBrokerAddr(),
requestHeader.getBrokerName(),
requestHeader.getBrokerId());
//设置响应状态码
response.setCode(ResponseCode.SUCCESS);
response.setRemark(null);
//返回响应结果
return response;
RouteInfoManager#unregisterBroker
try {
try {
//加入写锁-保护HashMap线程安全
this.lock.writeLock().lockInterruptibly();
//由于是从BrokerController远程调用来的请求-故不对BrokerAddr进行检查-直接进行移除
//移除brokerLiveTable中的Broker信息
BrokerLiveInfo brokerLiveInfo = this.brokerLiveTable.remove(brokerAddr);
log.info("unregisterBroker, remove from brokerLiveTable {}, {}",
brokerLiveInfo != null ? "OK" : "Failed",
brokerAddr
);
//维护filterServerTable
this.filterServerTable.remove(brokerAddr);
boolean removeBrokerName = false;
//根据brokername获取对应的BrokerData信息
BrokerData brokerData = this.brokerAddrTable.get(brokerName);
if (null != brokerData) {
//删除对应Broker信息
String addr = brokerData.getBrokerAddrs().remove(brokerId);
log.info("unregisterBroker, remove addr from brokerAddrTable {}, {}",
addr != null ? "OK" : "Failed",
brokerAddr
);
//如果当前BrokerData中已经没有其他Broker
if (brokerData.getBrokerAddrs().isEmpty()) {
//从BrokerAddrTable移除相应的Broker
this.brokerAddrTable.remove(brokerName);
log.info("unregisterBroker, remove name from brokerAddrTable OK, {}",
brokerName
);
removeBrokerName = true;
}
}
if (removeBrokerName) {
//在clusterAddrTable中通过集群名称获取对应的Broker集合
Set<String> nameSet = this.clusterAddrTable.get(clusterName);
if (nameSet != null) {
//移除该集合中的Broker
boolean removed = nameSet.remove(brokerName);
log.info("unregisterBroker, remove name from clusterAddrTable {}, {}",
removed ? "OK" : "Failed",
brokerName);
//如果该集群中的Broker集合为空-移除该集群
if (nameSet.isEmpty()) {
this.clusterAddrTable.remove(clusterName);
log.info("unregisterBroker, remove cluster from clusterAddrTable {}",
clusterName
);
}
}
//移除该Broker下的所有主题Topic
this.removeTopicByBrokerName(brokerName);
}
} finally {
//释放写锁
this.lock.writeLock().unlock();
}
} catch (Exception e) {
log.error("unregisterBroker Exception", e);
}
3.4路由发现
RocketMQ路由发现是非实时的，当Topic路由出现变化后，NameServer不会主动推送给客户端，而是由客户端定时拉取主题最新的路由。
DefaultRequestProcessor#processRequest
switch (request.getCode()) {
case RequestCode.GET_ROUTEINFO_BY_TOPIC:
return this.getRouteInfoByTopic(ctx, request);
}
DefaultRequestProcessor#getRouteInfoByTopic
//远程调用返回的响应结果
final RemotingCommand response = RemotingCommand.createResponseCommand(null);
//解析获取路由信息的请求头
final GetRouteInfoRequestHeader requestHeader =
(GetRouteInfoRequestHeader) request.decodeCommandCustomHeader(GetRouteInfoRequestHeader.class);
//调用RouteInfoManager中的方法,从路由表topicQueueTable、brokerAddrTable、filterServerTable中
//分别填充TopicRouteData的List、List、filterServer
TopicRouteData topicRouteData = this.namesrvController.getRouteInfoManager().pickupTopicRouteData(requestHeader.getTopic());
//如果找到主题对应你的路由信息并且该主题为顺序消息
//则从NameServer KVConfig中获取关于顺序消息相关的配置填充路由信息
if (topicRouteData != null) {
if (this.namesrvController.getNamesrvConfig().isOrderMessageEnable()) {
String orderTopicConf =
this.namesrvController.getKvConfigManager().getKVConfig(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG,
requestHeader.getTopic());
topicRouteData.setOrderTopicConf(orderTopicConf);
}
byte[] content = topicRouteData.encode();
//填充响应体和状态码
response.setBody(content);
response.setCode(ResponseCode.SUCCESS);
response.setRemark(null);
return response;
}
//设置响应码-主题不存在
response.setCode(ResponseCode.TOPIC_NOT_EXIST);
response.setRemark("No topic route info in name server for the topic: " + requestHeader.getTopic()
+ FAQUrl.suggestTodo(FAQUrl.APPLY_TOPIC_URL));
return response;
RouteInfoManager#pickupTopicRouteData
//创建主题路由信息对象
TopicRouteData topicRouteData = new TopicRouteData();
//是否找到对应队列的标识
boolean foundQueueData = false;
//是否找到对应Broker的标识
boolean foundBrokerData = false;
Set<String> brokerNameSet = new HashSet<String>();
List<BrokerData> brokerDataList = new LinkedList<BrokerData>();
topicRouteData.setBrokerDatas(brokerDataList);
HashMap<String, List<String>> filterServerMap = new HashMap<String, List<String>>();
topicRouteData.setFilterServerTable(filterServerMap);
try {
try {
//加入读锁
this.lock.readLock().lockInterruptibly();
//从topicQueueTable中通过主题topic查找Broker列表
List<QueueData> queueDataList = this.topicQueueTable.get(topic);
if (queueDataList != null) {
//填充Broker信息到topicRouteData.QueueDatas
topicRouteData.setQueueDatas(queueDataList);
foundQueueData = true;
Iterator<QueueData> it = queueDataList.iterator();
while (it.hasNext()) {
QueueData qd = it.next();
brokerNameSet.add(qd.getBrokerName());
}
//遍历Broker集合
for (String brokerName : brokerNameSet) {
//从brokerAddrTable中通过BrokerName进行查找
BrokerData brokerData = this.brokerAddrTable.get(brokerName);
if (null != brokerData) {
BrokerData brokerDataClone = new BrokerData(brokerData.getCluster(), brokerData.getBrokerName(), (HashMap<Long, String>) brokerData.getBrokerAddrs().clone());
//填充BrokerData信息到brokerDatas
brokerDataList.add(brokerDataClone);
foundBrokerData = true;
for (final String brokerAddr : brokerDataClone.getBrokerAddrs().values()) {
List<String> filterServerList = this.filterServerTable.get(brokerAddr);
filterServerMap.put(brokerAddr, filterServerList);
}
}
}
}
} finally {
//释放读锁
this.lock.readLock().unlock();
}
} catch (Exception e) {
log.error("pickupTopicRouteData Exception", e);
}
log.debug("pickupTopicRouteData {} {}", topic, topicRouteData);
if (foundBrokerData && foundQueueData) {
return topicRouteData;
}
return null;
3.5总结
- 路由注册：Broker启动之后会将自己的信息注册到NameServer，NameServer收到Broker心跳包之后会更新BrokerLiveTable中对应的Broker的相关信息，特别记录
lastUpdateTimestamp。 - 心跳机制：Broker会每隔30s向NameServer发送心跳包，告诉NameServer自己的运行状态良好。
- 路由发现：NameServer中的主题Topic信息更新之后，NameServer并不会实时将数据推送给订阅方Producer，而需要Producer自行通过Topic来查询路由信息。
- 路由删除：
- Broker异常宕机：NameServer每隔10s扫描BrokerLiveTable，检查表中各个Broker最新的发送心跳包时间，如果这个时间与当前系统时间差超过120s，则该Broker会被视作已掉线，NameServer会将这个Broker从表中删除，并且更新各个表中与该Broker有关的所有信息。
- Broker正常下线：NameServer接受到BrokerController发送来的
UNREGISTER_BROKER请求之后，会执行上述步骤，对路由信息进行更新。
以上。
本文仅作为个人学习使用，如有不足或者错误请指正！