在RocketMQ中，使用NamesrvStartup作为启动类
主函数作为其启动的入口：
public static void main(String[] args) {
main0(args);
}main0方法：
public static NamesrvController main0(String[] args) {
try {
NamesrvController controller = createNamesrvController(args);
start(controller);
String tip = "The Name Server boot success. serializeType=" + RemotingCommand.getSerializeTypeConfigInThisServer();
log.info(tip);
System.out.printf("%s%n", tip);
return controller;
} catch (Throwable e) {
e.printStackTrace();
System.exit(-1);
}
return null;
}首先通过createNamesrvController方法生成NameServer的控制器NamesrvController
createNamesrvController方法：
public static NamesrvController createNamesrvController(String[] args) throws IOException, JoranException {
System.setProperty(RemotingCommand.REMOTING_VERSION_KEY, Integer.toString(MQVersion.CURRENT_VERSION));
//PackageConflictDetect.detectFastjson();
Options options = ServerUtil.buildCommandlineOptions(new Options());
commandLine = ServerUtil.parseCmdLine("mqnamesrv", args, buildCommandlineOptions(options), new PosixParser());
if (null == commandLine) {
System.exit(-1);
return null;
}
final NamesrvConfig namesrvConfig = new NamesrvConfig();
final NettyServerConfig nettyServerConfig = new NettyServerConfig();
nettyServerConfig.setListenPort(9876);
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();
}
}
if (commandLine.hasOption('p')) {
InternalLogger console = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_CONSOLE_NAME);
MixAll.printObjectProperties(console, namesrvConfig);
MixAll.printObjectProperties(console, nettyServerConfig);
System.exit(0);
}
MixAll.properties2Object(ServerUtil.commandLine2Properties(commandLine), namesrvConfig);
if (null == namesrvConfig.getRocketmqHome()) {
System.out.printf("Please set the %s variable in your environment to match the location of the RocketMQ installation%n", MixAll.ROCKETMQ_HOME_ENV);
System.exit(-2);
}
LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
JoranConfigurator configurator = new JoranConfigurator();
configurator.setContext(lc);
lc.reset();
configurator.doConfigure(namesrvConfig.getRocketmqHome() + "/conf/logback_namesrv.xml");
log = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
MixAll.printObjectProperties(log, namesrvConfig);
MixAll.printObjectProperties(log, nettyServerConfig);
final NamesrvController controller = new NamesrvController(namesrvConfig, nettyServerConfig);
// remember all configs to prevent discard
controller.getConfiguration().registerConfig(properties);
return controller;
}这里创建了两个实体类NamesrvConfig和NettyServerConfig
这两个实体类对应了其配置文件中的配置
NamesrvConfig：
private String rocketmqHome = System.getProperty(MixAll.ROCKETMQ_HOME_PROPERTY, System.getenv(MixAll.ROCKETMQ_HOME_ENV));
private String kvConfigPath = System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "kvConfig.json";
private String configStorePath = System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "namesrv.properties";
private String productEnvName = "center";
private boolean clusterTest = false;
private boolean orderMessageEnable = false;NettyServerConfig：
private int listenPort = 8888;
private int serverWorkerThreads = 8;
private int serverCallbackExecutorThreads = 0;
private int serverSelectorThreads = 3;
private int serverOnewaySemaphoreValue = 256;
private int serverAsyncSemaphoreValue = 64;
private int serverChannelMaxIdleTimeSeconds = 120;
private int serverSocketSndBufSize = NettySystemConfig.socketSndbufSize // 65535;
private int serverSocketRcvBufSize = NettySystemConfig.socketRcvbufSize // 65535;
private boolean serverPooledByteBufAllocatorEnable = true;对应如下配置文件：
##
# 名称：NamesrvConfig.rocketmqHome <String>
# 默认值：(通过 sh mqnamesrv 设置 ROCKETMQ_HOME 环境变量，在源程序中获取环境变量得
# 到的目录)
# 描述：RocketMQ 主目录
# 建议：不主动配置
##
rocketmqHome = /usr/rocketmq
##
# 名称：NamesrvConfig.kvConfigPath <String>
# 默认值：$user.home/namesrv/kvConfig.json <在源程序中获取用户环境变量后生成>
# 描述：kv 配置文件路径，包含顺序消息主题的配置信息
# 建议：启用顺序消息时配置
##
kvConfigPath = /root/namesrv/kvConfig.json
##
# 名称：NamesrvConfig.configStorePath <String>
# 默认值：$user.home/namesrv/namesrv.properties <在源程序中获取用户环境变量后生成>
# 描述：NameServer 配置文件路径
# 建议：启动时通过 -c 指定
##
configStorePath = /root/namesrv/namesrv.properties
##
# 名称：NamesrvConfig.clusterTest <boolean>
# 默认值：false <在源程序中初始化字段时指定>
# 描述：是否开启集群测试
# 建议：不主动配置
##
clusterTest = false
##
# 名称：NamesrvConfig.orderMessageEnable <boolean>
# 默认值：false <在源程序中初始化字段时指定>
# 描述：是否支持顺序消息
# 建议：启用顺序消息时配置
##
orderMessageEnable = false
##
# 名称：NettyServerConfig.listenPort <int>
# 默认值：9876 <在源程序中初始化后单独设置>
# 描述：服务端监听端口
# 建议：不主动配置
##
listenPort = 9876
##
# 名称：NettyServerConfig.serverWorkerThreads <int>
# 默认值：8 <在源程序中初始化字段时指定>
# 描述：Netty 业务线程池线程个数
# 建议：不主动配置
##
serverWorkerThreads = 8
##
# 名称：NettyServerConfig.serverCallbackExecutorThreads <int>
# 默认值：0 <在源程序中初始化字段时指定>
# 描述：Netty public 任务线程池线程个数，Netty 网络设计，根据业务类型会创建不同的线程池，比如处理发送消息、消息消费、心跳检测等。如果该业务类型(RequestCode)未注册线程池，则由 public 线程池执行
# 建议：
##
serverCallbackExecutorThreads = 0
##
# 名称：NettyServerConfig.serverSelectorThreads <int>
# 默认值：3 <在源程序中初始化字段时指定>
# 描述：IO 线程池线程个数，主要是 NameServer、Broker 端解析请求、返回响应的线程个数，这类线程池主要是处理网络请求的，解析请求包，然后转发到各个业务线程池完成具体的业务操作，然后将结果再返回调用方
# 建议：不主动配置
##
serverSelectorThreads = 3
##
# 名称：NettyServerConfig.serverOnewaySemaphoreValue <int>
# 默认值：256 <在源程序中初始化字段时指定>
# 描述：send oneway 消息请求并发度
# 建议：不主动配置
##
serverOnewaySemaphoreValue = 256
##
# 名称：NettyServerConfig.serverAsyncSemaphoreValue <int>
# 默认值：64 <在源程序中初始化字段时指定>
# 描述：异步消息发送最大并发度
# 建议：不主动配置
##
serverAsyncSemaphoreValue = 64
##
# 名称：NettyServerConfig.serverChannelMaxIdleTimeSeconds <int>
# 默认值：120 <在源程序中初始化字段时指定>
# 描述：网络连接最大空闲时间，单位秒，如果连接空闲时间超过该参数设置的值，连接将被关闭
# 建议：不主动配置
##
serverChannelMaxIdleTimeSeconds = 120
##
# 名称：NettyServerConfig.serverSocketSndBufSize <int>
# 默认值：65535 <在源程序中初始化字段时指定>
# 描述：网络 socket 发送缓存区大小，单位 B，即默认为 64KB
# 建议：不主动配置
##
serverSocketSndBufSize = 65535
##
# 名称：NettyServerConfig.serverSocketRcvBufSize <int>
# 默认值：65535 <在源程序中初始化字段时指定>
# 描述：网络 socket 接收缓存区大小，单位 B，即默认为 64KB
# 建议：不主动配置
##
serverSocketRcvBufSize = 65535
##
# 名称：NettyServerConfig.serverPooledByteBufAllocatorEnable <int>
# 默认值：true <在源程序中初始化字段时指定>
# 描述：ByteBuffer 是否开启缓存，建议开启
# 建议：不主动配置
##
serverPooledByteBufAllocatorEnable = true
##
# 名称：NettyServerConfig.useEpollNativeSelector <int>
# 默认值：false <在源程序中初始化字段时指定>
# 描述：是否启用 Epoll IO 模型
# 建议：Linux 环境开启
##
useEpollNativeSelector = true接下来是对‘-c’命令下配置文件的加载，以及‘-p’命令下namesrvConfig和nettyServerConfig属性的打印
后续是对日志的一系列配置
在完成这些后，会根据namesrvConfig和nettyServerConfig创建NamesrvController实例
NamesrvController：
public NamesrvController(NamesrvConfig namesrvConfig, NettyServerConfig nettyServerConfig) {
this.namesrvConfig = namesrvConfig;
this.nettyServerConfig = nettyServerConfig;
this.kvConfigManager = new KVConfigManager(this);
this.routeInfoManager = new RouteInfoManager();
this.brokerHousekeepingService = new BrokerHousekeepingService(this);
this.configuration = new Configuration(
log,
this.namesrvConfig, this.nettyServerConfig
);
this.configuration.setStorePathFromConfig(this.namesrvConfig, "configStorePath");
}可以看到这里创建了一个KVConfigManager和一个RouteInfoManager
KVConfigManager：
public class KVConfigManager {
private final NamesrvController namesrvController;
private final HashMap<String/* Namespace */, HashMap<String/* Key */, String/* Value */>> configTable =
new HashMap<String, HashMap<String, String>>();
public KVConfigManager(NamesrvController namesrvController) {
this.namesrvController = namesrvController;
}
......
}KVConfigManager通过建立configTable管理KV
RouteInfoManager：
public class RouteInfoManager {
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;
private final static long BROKER_CHANNEL_EXPIRED_TIME = 1000 * 60 * 2;
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);
}
......
}RouteInfoManager则记录了这些路由信息，其中BROKER_CHANNEL_EXPIRED_TIME 表示允许的不活跃的Broker存活时间
在NamesrvController中还创建了一个BrokerHousekeepingService：
public class BrokerHousekeepingService implements ChannelEventListener {
private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
private final NamesrvController namesrvController;
public BrokerHousekeepingService(NamesrvController namesrvController) {
this.namesrvController = namesrvController;
}
@Override
public void onChannelConnect(String remoteAddr, Channel channel) {
}
@Override
public void onChannelClose(String remoteAddr, Channel channel) {
this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
}
@Override
public void onChannelException(String remoteAddr, Channel channel) {
this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
}
@Override
public void onChannelIdle(String remoteAddr, Channel channel) {
this.namesrvController.getRouteInfoManager().onChannelDestroy(remoteAddr, channel);
}
}可以看到这是一个ChannelEventListener，用来处理Netty的中的异步事件监听
在创建完NamesrvController后，回到main0，调用start方法，真正开启NameServer服务
start方法：
public static NamesrvController start(final NamesrvController controller) throws Exception {
if (null == controller) {
throw new IllegalArgumentException("NamesrvController is null");
}
boolean initResult = controller.initialize();
if (!initResult) {
controller.shutdown();
System.exit(-3);
}
Runtime.getRuntime().addShutdownHook(new ShutdownHookThread(log, new Callable<Void>() {
@Override
public Void call() throws Exception {
controller.shutdown();
return null;
}
}));
controller.start();
return controller;
}首先调用NamesrvController的initialize方法：
public boolean initialize() {
this.kvConfigManager.load();
this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.brokerHousekeepingService);
this.remotingExecutor =
Executors.newFixedThreadPool(nettyServerConfig.getServerWorkerThreads(), new ThreadFactoryImpl("RemotingExecutorThread_"));
this.registerProcessor();
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
NamesrvController.this.routeInfoManager.scanNotActiveBroker();
}
}, 5, 10, TimeUnit.SECONDS);
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
NamesrvController.this.kvConfigManager.printAllPeriodically();
}
}, 1, 10, TimeUnit.MINUTES);
if (TlsSystemConfig.tlsMode != TlsMode.DISABLED) {
// Register a listener to reload SslContext
try {
fileWatchService = new FileWatchService(
new String[] {
TlsSystemConfig.tlsServerCertPath,
TlsSystemConfig.tlsServerKeyPath,
TlsSystemConfig.tlsServerTrustCertPath
},
new FileWatchService.Listener() {
boolean certChanged, keyChanged = false;
@Override
public void onChanged(String 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();
}
});
} catch (Exception e) {
log.warn("FileWatchService created error, can't load the certificate dynamically");
}
}
return true;
}先通过kvConfigManager的load方法，向KVConfigManager中的map加载之前配置好的KV文件路径下的键值对
public void load() {
String content = null;
try {
content = MixAll.file2String(this.namesrvController.getNamesrvConfig().getKvConfigPath());
} catch (IOException e) {
log.warn("Load KV config table exception", e);
}
if (content != null) {
KVConfigSerializeWrapper kvConfigSerializeWrapper =
KVConfigSerializeWrapper.fromJson(content, KVConfigSerializeWrapper.class);
if (null != kvConfigSerializeWrapper) {
this.configTable.putAll(kvConfigSerializeWrapper.getConfigTable());
log.info("load KV config table OK");
}
}
}方法比较简单，将JSON形式的KV文件包装成KVConfigSerializeWrapper，通过getConfigTable方法转换成map放在configTable中
完成KV加载后，建立了一个NettyRemotingServer，即Netty服务器
public NettyRemotingServer(final NettyServerConfig nettyServerConfig,
final ChannelEventListener channelEventListener) {
super(nettyServerConfig.getServerOnewaySemaphoreValue(), nettyServerConfig.getServerAsyncSemaphoreValue());
this.serverBootstrap = new ServerBootstrap();
this.nettyServerConfig = nettyServerConfig;
this.channelEventListener = channelEventListener;
int publicThreadNums = nettyServerConfig.getServerCallbackExecutorThreads();
if (publicThreadNums <= 0) {
publicThreadNums = 4;
}
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()) {
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()));
}
});
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 {
this.eventLoopGroupBoss = new NioEventLoopGroup(1, new ThreadFactory() {
private AtomicInteger threadIndex = new AtomicInteger(0);
@Override
public Thread newThread(Runnable r) {
return new Thread(r, String.format("NettyNIOBoss_%d", this.threadIndex.incrementAndGet()));
}
});
this.eventLoopGroupSelector = new NioEventLoopGroup(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("NettyServerNIOSelector_%d_%d", threadTotal, this.threadIndex.incrementAndGet()));
}
});
}
loadSslContext();
}这里创建了ServerBootstrap
channelEventListener就是刚才创建的BrokerHousekeepingService
然后根据是否使用epoll，选择创建两个合适的EventLoopGroup
创建完成后，通过loadSslContext完成对SSL和TLS的设置
回到initialize方法，在创建完Netty的服务端后，调用registerProcessor方法：
private void registerProcessor() {
if (namesrvConfig.isClusterTest()) {
this.remotingServer.registerDefaultProcessor(new ClusterTestRequestProcessor(this, namesrvConfig.getProductEnvName()),
this.remotingExecutor);
} else {
this.remotingServer.registerDefaultProcessor(new DefaultRequestProcessor(this), this.remotingExecutor);
}
}这里和是否设置了clusterTest集群测试有关，默认关闭
在默认情况下创建了DefaultRequestProcessor，这个类很重要，后面会详细说明，然后通过remotingServer的registerDefaultProcessor方法，将DefaultRequestProcessor注册给Netty服务器：
public void registerDefaultProcessor(NettyRequestProcessor processor, ExecutorService executor) {
this.defaultRequestProcessor = new Pair<NettyRequestProcessor, ExecutorService>(processor, executor);
}在做完这些后，提交了两个定时任务
①定时清除不活跃的Broker
RouteInfoManager的scanNotActiveBroker方法：
public void scanNotActiveBroker() {
Iterator<Entry<String, BrokerLiveInfo>> it = this.brokerLiveTable.entrySet().iterator();
while (it.hasNext()) {
Entry<String, BrokerLiveInfo> next = it.next();
long last = next.getValue().getLastUpdateTimestamp();
if ((last + BROKER_CHANNEL_EXPIRED_TIME) < System.currentTimeMillis()) {
RemotingUtil.closeChannel(next.getValue().getChannel());
it.remove();
log.warn("The broker channel expired, {} {}ms", next.getKey(), BROKER_CHANNEL_EXPIRED_TIME);
this.onChannelDestroy(next.getKey(), next.getValue().getChannel());
}
}
}这里比较简单，在之前RouteInfoManager中创建的brokerLiveTable表中遍历所有BrokerLiveInfo，找到超出规定时间BROKER_CHANNEL_EXPIRED_TIME的BrokerLiveInfo信息进行删除，同时关闭Channel
而onChannelDestroy方法，会对其他几张表进行相关联的删除工作，代码重复量大就不细说了
BrokerLiveInfo记录了Broker的活跃度信息：
private long lastUpdateTimestamp;
private DataVersion dataVersion;
private Channel channel;
private String haServerAddr;lastUpdateTimestamp记录上一次更新时间戳，是其活跃性的关键
②定时完成configTable的日志记录
KVConfigManager的printAllPeriodically方法：
public void printAllPeriodically() {
try {
this.lock.readLock().lockInterruptibly();
try {
log.info("--------------------------------------------------------");
{
log.info("configTable SIZE: {}", this.configTable.size());
Iterator<Entry<String, HashMap<String, String>>> it =
this.configTable.entrySet().iterator();
while (it.hasNext()) {
Entry<String, HashMap<String, String>> next = it.next();
Iterator<Entry<String, String>> itSub = next.getValue().entrySet().iterator();
while (itSub.hasNext()) {
Entry<String, String> nextSub = itSub.next();
log.info("configTable NS: {} Key: {} Value: {}", next.getKey(), nextSub.getKey(),
nextSub.getValue());
}
}
}
} finally {
this.lock.readLock().unlock();
}
} catch (InterruptedException e) {
log.error("printAllPeriodically InterruptedException", e);
}
}很简单，根据configTable表的内容，完成KV的日志记录
在创建完这两个定时任务后会注册一个侦听器，以便完成SslContext的重新加载
initialize随之结束，之后是对关闭事件的处理
最后调用NamesrvController的start，此时才是真正的开启物理上的服务
NamesrvController的start方法:
public void start() throws Exception {
this.remotingServer.start();
if (this.fileWatchService != null) {
this.fileWatchService.start();
}
}这里实际上就是开启的Netty服务端
NettyRemotingServer的start方法：
public void start() {
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());
}
});
ServerBootstrap childHandler =
this.serverBootstrap.group(this.eventLoopGroupBoss, this.eventLoopGroupSelector)
.channel(useEpoll() ? EpollServerSocketChannel.class : NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 1024)
.option(ChannelOption.SO_REUSEADDR, true)
.option(ChannelOption.SO_KEEPALIVE, false)
.childOption(ChannelOption.TCP_NODELAY, true)
.childOption(ChannelOption.SO_SNDBUF, nettyServerConfig.getServerSocketSndBufSize())
.childOption(ChannelOption.SO_RCVBUF, nettyServerConfig.getServerSocketRcvBufSize())
.localAddress(new InetSocketAddress(this.nettyServerConfig.getListenPort()))
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline()
.addLast(defaultEventExecutorGroup, HANDSHAKE_HANDLER_NAME,
new HandshakeHandler(TlsSystemConfig.tlsMode))
.addLast(defaultEventExecutorGroup,
new NettyEncoder(),
new NettyDecoder(),
new IdleStateHandler(0, 0, nettyServerConfig.getServerChannelMaxIdleTimeSeconds()),
new NettyConnectManageHandler(),
new NettyServerHandler()
);
}
});
if (nettyServerConfig.isServerPooledByteBufAllocatorEnable()) {
childHandler.childOption(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
}
try {
ChannelFuture sync = this.serverBootstrap.bind().sync();
InetSocketAddress addr = (InetSocketAddress) sync.channel().localAddress();
this.port = addr.getPort();
} catch (InterruptedException e1) {
throw new RuntimeException("this.serverBootstrap.bind().sync() InterruptedException", e1);
}
if (this.channelEventListener != null) {
this.nettyEventExecutor.start();
}
this.timer.scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
try {
NettyRemotingServer.this.scanResponseTable();
} catch (Throwable e) {
log.error("scanResponseTable exception", e);
}
}
}, 1000 * 3, 1000);
}可以看到也就是正常的Netty服务端启动流程
在childHandler的绑定中，可以看到向pipeline绑定了一个NettyServerHandler：
class NettyServerHandler extends SimpleChannelInboundHandler<RemotingCommand> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
processMessageReceived(ctx, msg);
}
}那么当客户端和NameServre端建立连接后，之间传输的消息会通过processMessageReceived方法进行处理
processMessageReceived方法：
public void processMessageReceived(ChannelHandlerContext ctx, RemotingCommand msg) throws Exception {
final RemotingCommand cmd = msg;
if (cmd != null) {
switch (cmd.getType()) {
case REQUEST_COMMAND:
processRequestCommand(ctx, cmd);
break;
case RESPONSE_COMMAND:
processResponseCommand(ctx, cmd);
break;
default:
break;
}
}
}根据消息类型（请求消息、响应消息），使用不同的处理
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();
if (pair != null) {
Runnable run = new Runnable() {
@Override
public void run() {
try {
doBeforeRpcHooks(RemotingHelper.parseChannelRemoteAddr(ctx.channel()), cmd);
final RemotingCommand response = pair.getObject1().processRequest(ctx, cmd);
doAfterRpcHooks(RemotingHelper.parseChannelRemoteAddr(ctx.channel()), cmd, response);
if (!cmd.isOnewayRPC()) {
if (response != null) {
response.setOpaque(opaque);
response.markResponseType();
try {
ctx.writeAndFlush(response);
} catch (Throwable e) {
log.error("process request over, but response failed", e);
log.error(cmd.toString());
log.error(response.toString());
}
} else {
}
}
} catch (Throwable e) {
log.error("process request exception", e);
log.error(cmd.toString());
if (!cmd.isOnewayRPC()) {
final RemotingCommand response = RemotingCommand.createResponseCommand(RemotingSysResponseCode.SYSTEM_ERROR,
RemotingHelper.exceptionSimpleDesc(e));
response.setOpaque(opaque);
ctx.writeAndFlush(response);
}
}
}
};
if (pair.getObject1().rejectRequest()) {
final RemotingCommand response = RemotingCommand.createResponseCommand(RemotingSysResponseCode.SYSTEM_BUSY,
"[REJECTREQUEST]system busy, start flow control for a while");
response.setOpaque(opaque);
ctx.writeAndFlush(response);
return;
}
try {
final RequestTask requestTask = new RequestTask(run, ctx.channel(), cmd);
pair.getObject2().submit(requestTask);
} catch (RejectedExecutionException e) {
if ((System.currentTimeMillis() % 10000) == 0) {
log.warn(RemotingHelper.parseChannelRemoteAddr(ctx.channel())
+ ", too many requests and system thread pool busy, RejectedExecutionException "
+ pair.getObject2().toString()
+ " request code: " + cmd.getCode());
}
if (!cmd.isOnewayRPC()) {
final RemotingCommand response = RemotingCommand.createResponseCommand(RemotingSysResponseCode.SYSTEM_BUSY,
"[OVERLOAD]system busy, start flow control for a while");
response.setOpaque(opaque);
ctx.writeAndFlush(response);
}
}
} else {
String error = " request type " + cmd.getCode() + " not supported";
final RemotingCommand response =
RemotingCommand.createResponseCommand(RemotingSysResponseCode.REQUEST_CODE_NOT_SUPPORTED, error);
response.setOpaque(opaque);
ctx.writeAndFlush(response);
log.error(RemotingHelper.parseChannelRemoteAddr(ctx.channel()) + error);
}
}在这里创建了一个Runnable提交给线程池，这个Runnable的核心是
final RemotingCommand response = pair.getObject1().processRequest(ctx, cmd);实际上调用的就是前面说过的DefaultRequestProcessor的processRequest方法：
public RemotingCommand processRequest(ChannelHandlerContext ctx,
RemotingCommand request) throws RemotingCommandException {
if (ctx != null) {
log.debug("receive request, {} {} {}",
request.getCode(),
RemotingHelper.parseChannelRemoteAddr(ctx.channel()),
request);
}
switch (request.getCode()) {
case RequestCode.PUT_KV_CONFIG:
return this.putKVConfig(ctx, request);
case RequestCode.GET_KV_CONFIG:
return this.getKVConfig(ctx, request);
case RequestCode.DELETE_KV_CONFIG:
return this.deleteKVConfig(ctx, request);
case RequestCode.QUERY_DATA_VERSION:
return queryBrokerTopicConfig(ctx, request);
case RequestCode.REGISTER_BROKER:
Version brokerVersion = MQVersion.value2Version(request.getVersion());
if (brokerVersion.ordinal() >= MQVersion.Version.V3_0_11.ordinal()) {
return this.registerBrokerWithFilterServer(ctx, request);
} else {
return this.registerBroker(ctx, request);
}
case RequestCode.UNREGISTER_BROKER:
return this.unregisterBroker(ctx, request);
case RequestCode.GET_ROUTEINTO_BY_TOPIC:
return this.getRouteInfoByTopic(ctx, request);
case RequestCode.GET_BROKER_CLUSTER_INFO:
return this.getBrokerClusterInfo(ctx, request);
case RequestCode.WIPE_WRITE_PERM_OF_BROKER:
return this.wipeWritePermOfBroker(ctx, request);
case RequestCode.GET_ALL_TOPIC_LIST_FROM_NAMESERVER:
return getAllTopicListFromNameserver(ctx, request);
case RequestCode.DELETE_TOPIC_IN_NAMESRV:
return deleteTopicInNamesrv(ctx, request);
case RequestCode.GET_KVLIST_BY_NAMESPACE:
return this.getKVListByNamespace(ctx, request);
case RequestCode.GET_TOPICS_BY_CLUSTER:
return this.getTopicsByCluster(ctx, request);
case RequestCode.GET_SYSTEM_TOPIC_LIST_FROM_NS:
return this.getSystemTopicListFromNs(ctx, request);
case RequestCode.GET_UNIT_TOPIC_LIST:
return this.getUnitTopicList(ctx, request);
case RequestCode.GET_HAS_UNIT_SUB_TOPIC_LIST:
return this.getHasUnitSubTopicList(ctx, request);
case RequestCode.GET_HAS_UNIT_SUB_UNUNIT_TOPIC_LIST:
return this.getHasUnitSubUnUnitTopicList(ctx, request);
case RequestCode.UPDATE_NAMESRV_CONFIG:
return this.updateConfig(ctx, request);
case RequestCode.GET_NAMESRV_CONFIG:
return this.getConfig(ctx, request);
default:
break;
}
return null;
}这个方法很直观，根据不同的RequestCode，执行不同的方法，其中有熟悉的
REGISTER_BROKER 注册Broker
GET_ROUTEINTO_BY_TOPIC 获取Topic路由信息
而其相对性的方法执行就是通过查阅或者修改之前创建的表来完成
最后将相应的数据包装，在Runnable中通过Netty的writeAndFlush完成发送
至此NameServer的启动结束
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