rocketmq——NameServer
1、作用
NameServer是一个单独的服务，作为rocketmq这一整套微服务的注册中心，提供broker信息的管理和生产者消费者的请求路由
2、启动流程
首先下载好rocketmq的源码https://github.com/apache/rocketmq
我们进入到namesrv这个工程里，找到org.apache.rocketmq.namesrv下的NamesrvStartup类
这个是启动方法：
public static void main(String[] args) {
main0(args);
}public static NamesrvController main0(String[] args) {
try {
//1、首先会创建一个控制器
NamesrvController controller = createNamesrvController(args);
//2、启动它
start(controller);
return controller;
} catch (Throwable e) {
e.printStackTrace();
System.exit(-1);
}
return null;
}2.1、创建控制器——createNamesrvController
我们删掉了一些参数的校验和一些配置以保证最简初始化
public static NamesrvController createNamesrvController(String[] args) throws IOException, JoranException {
//NamesrvConfig里包括日志、mq根路径、kv持久化路径、集群测试和顺序消费等配置
final NamesrvConfig namesrvConfig = new NamesrvConfig();
//web容器配置，就是常规的端口号、线程数、连接超时时间、缓存区大小
final NettyServerConfig nettyServerConfig = new NettyServerConfig();
//指定namesrv的端口号为9876
nettyServerConfig.setListenPort(9876);
//如果启动脚本里有-c，就读对应的配置文件，进行参数覆盖
if (commandLine.hasOption('c')) {
String file = commandLine.getOptionValue('c');
if (file != null) {
InputStream in = new BufferedInputStream(new FileInputStream(file));
properties = new Properties();
properties.load(in);
MixAll.properties2Object(properties, namesrvConfig);
MixAll.properties2Object(properties, nettyServerConfig);
namesrvConfig.setConfigStorePath(file);
System.out.printf("load config properties file OK, %s%n", file);
in.close();
}
}
final NamesrvController controller = new NamesrvController(namesrvConfig, nettyServerConfig);
return controller;
}2.2、启动namesrv——start
public static NamesrvController start(final NamesrvController controller) throws Exception {
//1、初始化
boolean initResult = controller.initialize();
//2、真正启动
controller.start();
return controller;
}2.2.1、初始化——initialize
public boolean initialize() {
//1、初始化web服务器
this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.brokerHousekeepingService);
//2、初始化线程池
this.remotingExecutor =
Executors.newFixedThreadPool(nettyServerConfig.getServerWorkerThreads(), new ThreadFactoryImpl("RemotingExecutorThread_"));
//3、注册了一个默认的远程处理器，不知道是干啥的，先跳过
this.registerProcessor();
//4、定时任务，每10秒扫描一次broker
//scanNotActiveBroker我就不贴了，默认是距离上次心跳成功两分钟以上，就判定broker失效并移除
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
NamesrvController.this.routeInfoManager.scanNotActiveBroker();
}
}, 5, 10, TimeUnit.SECONDS);
//5、定时任务，每10秒打印configTable里的kv
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
NamesrvController.this.kvConfigManager.printAllPeriodically();
}
}, 1, 10, TimeUnit.MINUTES);
//6、使用文件监听器，动态进行tls证书配置
if (TlsSystemConfig.tlsMode != TlsMode.DISABLED) {
fileWatchService = new FileWatchService(
new String[] {
TlsSystemConfig.tlsServerCertPath,
TlsSystemConfig.tlsServerKeyPath,
TlsSystemConfig.tlsServerTrustCertPath
},
new FileWatchService.Listener() {
boolean certChanged, keyChanged = false;
@Override
public void onChanged(String path) {
//这个path就是上面TlsSystemConfig传入的3个path
if (path.equals(TlsSystemConfig.tlsServerTrustCertPath)) {
log.info("The trust certificate changed, reload the ssl context");
reloadServerSslContext();
}
if (path.equals(TlsSystemConfig.tlsServerCertPath)) {
certChanged = true;
}
if (path.equals(TlsSystemConfig.tlsServerKeyPath)) {
keyChanged = true;
}
if (certChanged && keyChanged) {
log.info("The certificate and private key changed, reload the ssl context");
certChanged = keyChanged = false;
reloadServerSslContext();
}
}
private void reloadServerSslContext() {
((NettyRemotingServer) remotingServer).loadSslContext();
}
});
}
return true;
}2.2.1.1、初始化web服务器NettyRemotingServer
这个方法传入了一个brokerHousekeepingService，是在创建NamesrvController时初始化的，实现了ChannelEventListener，主要对Channel产生的事件做一些处理，
这里都调用了onChannelDestroy方法，里面的代码很长，但其实就干了一件事，移除本地缓存的broker信息，代码我就不贴了
public class BrokerHousekeepingService implements ChannelEventListener {
private final NamesrvController namesrvController;
public BrokerHousekeepingService(NamesrvController namesrvController) {
this.namesrvController = namesrvController;
}
@Override
public void onChannelConnect(String remoteAddr, Channel channel) {
}
//Channel关闭时
@Override
public void onChannelClose(String remoteAddr, Channel channel) {
this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
}
//Channel报异常时
@Override
public void onChannelException(String remoteAddr, Channel channel) {
this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
}
//Channel空闲时
@Override
public void onChannelIdle(String remoteAddr, Channel channel) {
this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
}
}初始化NettyRemotingServer
public NettyRemotingServer(final NettyServerConfig nettyServerConfig,
final ChannelEventListener channelEventListener) {
int publicThreadNums = nettyServerConfig.getServerCallbackExecutorThreads();
if (publicThreadNums <= 0) {
publicThreadNums = 4;
}
//publicExecutor是执行回调的线程池，最少4个线程
//在getCallbackExecutor方法中用到，这个方法被executeInvokeCallback调用，传入了一个ResponseFuture
//当producer或consumer的请求打到broker后，broker会异步执行请求逻辑，最后统一交给publicExecutor的线程响应
this.publicExecutor = Executors.newFixedThreadPool(publicThreadNums, new ThreadFactory() {
private AtomicInteger threadIndex = new AtomicInteger(0);
@Override
public Thread newThread(Runnable r) {
return new Thread(r, "NettyServerPublicExecutor_" + this.threadIndex.incrementAndGet());
}
});
if (useEpoll()) {
//使用epoll初始化boss和worker线程组
//boss线程组用来接收连接并分发给selector，一般都是单线程，绑定一个端口，从一个入口处理连接
this.eventLoopGroupBoss = new EpollEventLoopGroup(1, new ThreadFactory() {
private AtomicInteger threadIndex = new AtomicInteger(0);
@Override
public Thread newThread(Runnable r) {
return new Thread(r, String.format("NettyEPOLLBoss_%d", this.threadIndex.incrementAndGet()));
}
});
//selector线程组负责解析请求并将请求转发给worker线程组（2.2.2会看到）执行业务逻辑
//worker执行完成后交回给selector返回响应，selector默认3个线程
this.eventLoopGroupSelector = new EpollEventLoopGroup(nettyServerConfig.getServerSelectorThreads(), new ThreadFactory() {
private AtomicInteger threadIndex = new AtomicInteger(0);
private int threadTotal = nettyServerConfig.getServerSelectorThreads();
@Override
public Thread newThread(Runnable r) {
return new Thread(r, String.format("NettyServerEPOLLSelector_%d_%d", threadTotal, this.threadIndex.incrementAndGet()));
}
});
} else {
//使用NIO模式，省略
}
//最后进行ssl初始化，netty默认开启ssl，使用自签名证书进行安全认证
//你也可以配置相关JVM参数，把ssl配置文件、key和证书放到对应位置，参数都在TlsSystemConfig这个类里
loadSslContext();
}2.2.2、启动web服务器——start
执行完NamesrvController的初始化，就开始启动它
public void start() throws Exception {
//1、启动RemotingServer
this.remotingServer.start();
//2、启动FileWatchService，这个不是重点
if (this.fileWatchService != null) {
this.fileWatchService.start();
}
}里面最主要的方法就是启动这个web服务器
@Override
public void start() {
//1、初始化worker线程组，用来处理selector分发过来的业务请求，默认8个线程
this.defaultEventExecutorGroup = new DefaultEventExecutorGroup(
nettyServerConfig.getServerWorkerThreads(),
new ThreadFactory() {
private AtomicInteger threadIndex = new AtomicInteger(0);
@Override
public Thread newThread(Runnable r) {
return new Thread(r, "NettyServerCodecThread_" + this.threadIndex.incrementAndGet());
}
});
//2、初始化了握手、编码、连接管理（channel注册）、Server接收请求共4个处理器
prepareSharableHandlers();
//3、初始化netty的ServerBootstrap
ServerBootstrap childHandler =
this.serverBootstrap.group(this.eventLoopGroupBoss, this.eventLoopGroupSelector)
.channel(useEpoll() ? EpollServerSocketChannel.class : NioServerSocketChannel.class)
.localAddress(new InetSocketAddress(this.nettyServerConfig.getListenPort()))
//进行处理器的注册，入站按照注册顺序链式调用，出站逆序，使用的都是worker线程组
//注意这些handler分为入站和出站，会根据netty是接收请求还是发送请求选择不同的handler执行
//入站的handler都继承ChannelInboundHandlerAdapter
//出站的handler都继承ChannelOutboundHandlerAdapter
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline()
//入站
.addLast(defaultEventExecutorGroup, HANDSHAKE_HANDLER_NAME, handshakeHandler)
.addLast(defaultEventExecutorGroup,
//出站
encoder,
//入站
new NettyDecoder(),
//入站
new IdleStateHandler(0, 0, nettyServerConfig.getServerChannelMaxIdleTimeSeconds()),
//入站和出站
connectionManageHandler,
//入站
serverHandler
);
}
});
//4、绑定socket端口
ChannelFuture sync = this.serverBootstrap.bind().sync();
InetSocketAddress addr = (InetSocketAddress) sync.channel().localAddress();
this.port = addr.getPort();
if (this.channelEventListener != null) {
//5、启动brokerHousekeepingService事件监听器
this.nettyEventExecutor.start();
}
//6、启动定时任务，扫描ResponseTable，移除超时的请求
//注意rocketmq的一部分请求是全双工的，不会放到ResponseTable中
this.timer.scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
try {
NettyRemotingServer.this.scanResponseTable();
} catch (Throwable e) {
log.error("scanResponseTable exception", e);
}
}
}, 1000 * 3, 1000);
}3、注册路由
broker向namesrv发起注册请求，该请求会被NettyServerHandler处理，该类在NettyRemotingServer下
@ChannelHandler.Sharable
class NettyServerHandler extends SimpleChannelInboundHandler<RemotingCommand> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
processMessageReceived(ctx, msg);
}
}执行processMessageReceived方法接收请求
public void processMessageReceived(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
final RemotingCommand cmd = msg;
if (cmd != null) {
switch (cmd.getType()) {
case REQUEST_COMMAND:
//注册路由是一个请求，会进入处理请求的方法
processRequestCommand(ctx, cmd);
break;
case RESPONSE_COMMAND:
processResponseCommand(ctx, cmd);
break;
default:
break;
}
}
}真正处理请求调用processRequestCommand方法
public void processRequestCommand(final ChannelHandlerContext ctx, final RemotingCommand cmd) {
final Pair<NettyRequestProcessor, ExecutorService> matched = this.processorTable.get(cmd.getCode());
final Pair<NettyRequestProcessor, ExecutorService> pair = null == matched ? this.defaultRequestProcessor : matched;
final int opaque = cmd.getOpaque();
Runnable run = new Runnable() {
@Override
public void run() {
final RemotingResponseCallback callback = new RemotingResponseCallback() {
@Override
public void callback(RemotingCommand response) {
//callback
}
};
if (pair.getObject1() instanceof AsyncNettyRequestProcessor) {
//异步请求
AsyncNettyRequestProcessor processor = (AsyncNettyRequestProcessor)pair.getObject1();
//执行请求逻辑
processor.asyncProcessRequest(ctx, cmd, callback);
} else {
//同步请求
}
}
};
final RequestTask requestTask = new RequestTask(run, ctx.channel(), cmd);
pair.getObject2().submit(requestTask);
}以异步请求为例，调用AsyncNettyRequestProcessor的asyncProcessRequest方法
public void asyncProcessRequest(ChannelHandlerContext ctx, RemotingCommand request, RemotingResponseCallback responseCallback) throws Exception {
RemotingCommand response = processRequest(ctx, request);
responseCallback.callback(response);
}不管同步异步，最后都会调用DefaultRequestProcessor的processRequest方法
代码中我省略了一些case，包括producer和consumer调用namesrv获取broker信息这种请求，也在这里处理
@Override
public RemotingCommand processRequest(ChannelHandlerContext ctx,
RemotingCommand request) throws RemotingCommandException {
switch (request.getCode()) {
//省略一堆case
//这里的分支是进入注册broker的逻辑
case RequestCode.REGISTER_BROKER:
Version brokerVersion = MQVersion.value2Version(request.getVersion());
if (brokerVersion.ordinal() >= MQVersion.Version.V3_0_11.ordinal()) {
//我们用的版本是v4.8.0，v3.0.11后加入了filterServer进行过滤
return this.registerBrokerWithFilterServer(ctx, request);
} else {
return this.registerBroker(ctx, request);
}
//省略一堆case
default:
break;
}
return null;
}其实不管走哪个分支，最后都会调用registerBroker。我们先简单看一下registerBrokerWithFilterServer
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);
//1、冗余位数据校验
if (!checksum(ctx, request, requestHeader)) {
response.setCode(ResponseCode.SYSTEM_ERROR);
response.setRemark("crc32 not match");
return response;
}
RegisterBrokerBody registerBrokerBody = new RegisterBrokerBody();
//2、对请求流解码。数据没压缩用json解析，压缩了就用InflaterInputStream解析
registerBrokerBody = RegisterBrokerBody.decode(request.getBody(), requestHeader.isCompressed());
//3、本地缓存broker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;
}调用registerBroker进行注册
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();
Set<String> brokerNames = this.clusterAddrTable.get(clusterName);
if (null == brokerNames) {
brokerNames = new HashSet<String>();
//1、clusterAddrTable通过broker的集群名称找到集群下所有的broker名称
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>());
//2、brokerAddrTable通过broker的名称找到broker的详细信息
this.brokerAddrTable.put(brokerName, brokerData);
}
Map<Long, String> brokerAddrsMap = brokerData.getBrokerAddrs();
Iterator<Entry<Long, String>> it = brokerAddrsMap.entrySet().iterator();
while (it.hasNext()) {
Entry<Long, String> item = it.next();
//3、当相同IP的broker对应的brokerData记录的brokerId不同时，说明主从关系变了，先移除
if (null != brokerAddr && brokerAddr.equals(item.getValue()) && brokerId != item.getKey()) {
it.remove();
}
}
//4、设置brokerData内broker的IP
String oldAddr = brokerData.getBrokerAddrs().put(brokerId, brokerAddr);
registerFirst = registerFirst || (null == oldAddr);
if (this.isBrokerTopicConfigChanged(brokerAddr, topicConfigWrapper.getDataVersion())
|| registerFirst) {
ConcurrentMap<String, TopicConfig> tcTable =
topicConfigWrapper.getTopicConfigTable();
if (tcTable != null) {
for (Map.Entry<String, TopicConfig> entry : tcTable.entrySet()) {
//5、如果broker传过来的数据版本号DataVersion变了（包括数据生成的时间、计数值等），要更新队列信息
//看得出来应该是队列信息变了
this.createAndUpdateQueueData(brokerName, entry.getValue());
}
}
}
//6、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);
}
//7、维护filterServerTable
if (filterServerList != null) {
if (filterServerList.isEmpty()) {
this.filterServerTable.remove(brokerAddr);
} else {
this.filterServerTable.put(brokerAddr, filterServerList);
}
}
//8、不是主节点还会记录相关master的信息
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);
}
}
}
return result;
}调用createAndUpdateQueueData更新topic下的队列配置
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());
//总的来说，寻找流程是这样的topic->queue->broker
List<QueueData> queueDataList = this.topicQueueTable.get(topicConfig.getTopicName());
if (null == queueDataList) {
//为空就是第一次注册，直接放
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);
//不为空就先根据brokerName移除broker下的队列配置
it.remove();
}
}
}
if (addNewOne) {
//重新添加队列配置
queueDataList.add(queueData);
}
}
}执行完了之后，会一路返回到asyncProcessRequest，执行callBack方法进行全双工响应
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