NameServer是一个非常简单的Topic路由注册中心,其角色类似Dubbo中的zookeeper,支持Broker的动态注册与发现。主要包括两个功能:
public class NamesrvStartup {
private static InternalLogger log;
private static Properties properties = null;
private static CommandLine commandLine = null;
public static void main(String[] args) {
main0(args);
}
public static NamesrvController main0(String[] args) {
try {
NamesrvController controller = createNamesrvController(args);
//TODO:NameServer启动
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;
}
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知道了入口,那接下来我们就分析下它是如何启动的,启动的过程中都做了什么?从上面的部分代码中,不难看出,它首先就是创建NamesrvController
对象,然后启动(start()
方法),那我们就一步一步走进去看看细节.
NamesrvController
对象不要看代码比较多,其实主要就是创建3个对象,请往后看
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;
}
//TODO:创建NamesrvConfig对象
final NamesrvConfig namesrvConfig = new NamesrvConfig();
//TODO: 创建 NettyServerConfig 对象
final NettyServerConfig nettyServerConfig = new NettyServerConfig();
//TODO: 设置固定端口号9876,客户端连接的时候就是 nameserverip:9876
nettyServerConfig.setListenPort(9876);
//TODO: 读取命令行中 -c 参数值(如果指定该参数,它是一个配置文件)
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();
}
}
//TODO: 判断是否有 -p 参数值
if (commandLine.hasOption('p')) {
InternalLogger console = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_CONSOLE_NAME);
MixAll.printObjectProperties(console, namesrvConfig);
MixAll.printObjectProperties(console, nettyServerConfig);
System.exit(0);
}
//TODO:将命令行参数映射到 NamesrvConfig类中
MixAll.properties2Object(ServerUtil.commandLine2Properties(commandLine), namesrvConfig);
//TODO: 判断是否指定ROCKETMQ_HOME,本地运行时,必须要指定该值
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);
//TODO: 创建 NamesrvController 对象
final NamesrvController controller = new NamesrvController(namesrvConfig, nettyServerConfig);
// remember all configs to prevent discard
controller.getConfiguration().registerConfig(properties);
return controller;
}
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总结一下就是创建3个对象
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本文系转载,前往查看
如有侵权,请联系 cloudcommunity@tencent.com 删除。