ShenYu网关注册中心之Zookeeper注册原理

1、客户端注册流程

当客户端启动后，根据相关配置，读取属性信息，然后写入队列。以官方提供的 shenyu-examples-http 为例，开始源码分析。

1.1、读取配置

该例子是一个springboot项目，所以注册的入口往往在自动装配类中。不妨可以先看下项目的pom文件中引入了什么依赖：

<dependencies><dependency><groupId>org.apache.shenyu</groupId><artifactId>shenyu-spring-boot-starter-client-springmvc</artifactId><version>${project.version}</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-webflux</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-logging</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
</dependencies>

这里面看到就shenyu-spring-boot-starter-client-springmvc是跟ShenYu相关的，所以入口应该就在这个依赖内了，看下这个依赖的项目结构：

发现就是两个配置类，ShenyuSpringMvcClientInfoRegisterConfiguration由于使用了@Configuration(proxyBeanMethods = false)，暂时不用关注，重点关注ShenyuSpringMvcClientConfiguration，它是shenyu客户端http注册配置类。

/*** shenyu 客户端http注册配置类*/
@Configuration
// shenyu客户端通用配置类
@ImportAutoConfiguration(ShenyuClientCommonBeanConfiguration.class)
@ConditionalOnProperty(value = "shenyu.register.enabled", matchIfMissing = true, havingValue = "true")
public class ShenyuSpringMvcClientConfiguration {static {VersionUtils.checkDuplicate(ShenyuSpringMvcClientConfiguration.class);}/**** 监听并处理http元数据和URI信息的注册** @param clientConfig                   客户端注册配置* @param shenyuClientRegisterRepository 客户端注册类*/@Bean@ConditionalOnMissingBean(ClientRegisterConfiguration.class)// 这里的两个参数是由ShenyuClientCommonBeanConfiguration导入的public SpringMvcClientEventListener springHttpClientEventListener(final ShenyuClientConfig clientConfig,final ShenyuClientRegisterRepository shenyuClientRegisterRepository) {return new SpringMvcClientEventListener(clientConfig.getClient().get(RpcTypeEnum.HTTP.getName()), shenyuClientRegisterRepository);}
}

通过@Configuration表示这是一个配置类，通过@ImportAutoConfiguration引入ShenyuClientCommonBeanConfiguration配置类。

/*** shenyu客户端通用配置类，创建注册中心客户端通用的bean*/
@Configuration
@ConditionalOnProperty(value = "shenyu.register.enabled", matchIfMissing = true, havingValue = "true")
public class ShenyuClientCommonBeanConfiguration {/*** 根据注册中心配置通过SPI方式创建客户端注册类*/@Beanpublic ShenyuClientRegisterRepository shenyuClientRegisterRepository(final ShenyuRegisterCenterConfig config) {return ShenyuClientRegisterRepositoryFactory.newInstance(config);}/*** Shenyu 客户端注册中心配置，读取shenyu.register属性配置*/@Bean@ConfigurationProperties(prefix = "shenyu.register")public ShenyuRegisterCenterConfig shenyuRegisterCenterConfig() {return new ShenyuRegisterCenterConfig();}/*** Shenyu 客户端配置，读取shenyu.client属性配置*/@Bean@ConfigurationProperties(prefix = "shenyu")public ShenyuClientConfig shenyuClientConfig() {return new ShenyuClientConfig();}
}

ShenyuClientCommonBeanConfiguration是ShenYu客户端的通用配置类，创建了3个通用bean。

• ShenyuClientRegisterRepository：客户端注册类，用于将客户端接口信息注册到注册中心。
• ShenyuRegisterCenterConfig：ShenYu客户端注册中心配置类，读取shenyu.register属性配置。
• ShenyuClientConfig：ShenYu客户端配置类，读取shenyu.client属性配置。

1.1.1、用于注册的 ZookeeperClientRegisterRepository

上面生成的ShenyuClientRegisterRepository是用于实现客户端注册的接口，会根据注册中心的配置通过SPI方式创建客户端注册类，每一个注册方式都对应一个实现类。

目前支持7种注册类型：

• Http：HttpClientRegisterRepository
• Apollo：ApolloClientRegisterRepository
• Zookeeper：ZookeeperClientRegisterRepository
• Etcd：EtcdClientRegisterRepository
• Nacos：NacosClientRegisterRepository
• Consul：ConsulClientRegisterRepository
• Polaris：PolarisClientRegisterRepository

public final class ShenyuClientRegisterRepositoryFactory {private static final Map<String, ShenyuClientRegisterRepository> REPOSITORY_MAP = new ConcurrentHashMap<>();/*** 根据注册中心类型实例化注册服务*/public static ShenyuClientRegisterRepository newInstance(final ShenyuRegisterCenterConfig shenyuRegisterCenterConfig) {if (!REPOSITORY_MAP.containsKey(shenyuRegisterCenterConfig.getRegisterType())) {// 通过SPI方式创建客户端注册类ShenyuClientRegisterRepository result = ExtensionLoader.getExtensionLoader(ShenyuClientRegisterRepository.class).getJoin(shenyuRegisterCenterConfig.getRegisterType());// 初始化对应客户端注册类，比如创建zookeeper client，etcd client，admin平台的token等result.init(shenyuRegisterCenterConfig);ShenyuClientShutdownHook.set(result, shenyuRegisterCenterConfig.getProps());REPOSITORY_MAP.put(shenyuRegisterCenterConfig.getRegisterType(), result);return result;}return REPOSITORY_MAP.get(shenyuRegisterCenterConfig.getRegisterType());}
}

加载类型通过registerType指定，也就是我们在配置文件中指定的类型：

shenyu:register:registerType: zookeeperserverLists: http://localhost:2181

这里指定的是zookeeper，所以这里创建的就是ZookeeperClientRegisterRepository。
创建对应的注册客户端后，会调用init方法根据shenyu.register下的配置进行初始化：

@Join
public class ZookeeperClientRegisterRepository implements ShenyuClientRegisterRepository {@Overridepublic void init(final ShenyuRegisterCenterConfig config) {Properties props = config.getProps();int sessionTimeout = Integer.parseInt(props.getProperty("sessionTimeout", "3000"));int connectionTimeout = Integer.parseInt(props.getProperty("connectionTimeout", "3000"));int baseSleepTime = Integer.parseInt(props.getProperty("baseSleepTime", "1000"));int maxRetries = Integer.parseInt(props.getProperty("maxRetries", "3"));int maxSleepTime = Integer.parseInt(props.getProperty("maxSleepTime", String.valueOf(Integer.MAX_VALUE)));ZookeeperConfig zkConfig = new ZookeeperConfig(config.getServerLists());zkConfig.setBaseSleepTimeMilliseconds(baseSleepTime).setMaxRetries(maxRetries).setMaxSleepTimeMilliseconds(maxSleepTime).setSessionTimeoutMilliseconds(sessionTimeout).setConnectionTimeoutMilliseconds(connectionTimeout);String digest = props.getProperty("digest");if (!StringUtils.isEmpty(digest)) {zkConfig.setDigest(digest);}// 创建zookeeper客户端this.client = new ZookeeperClient(zkConfig);this.client.getClient().getConnectionStateListenable().addListener((c, newState) -> {if (newState == ConnectionState.RECONNECTED) {nodeDataMap.forEach((k, v) -> {if (!client.isExist(k)) {client.createOrUpdate(k, v, CreateMode.EPHEMERAL);LOGGER.info("zookeeper client register uri success: {}", v);}});}});// 启动客户端client.start();}
}

这里主要就是创建zookeeper的客户端，为后面的发送注册数据做准备。其他注册类型的ShenyuClientRegisterRepository也一样，创建各自注册中心的client，连接注册中心，为发送数据做准备。类注解@Join用于SPI的加载。

1.1.2、用于扫描构建 元数据 和 URI 的 SpringMvcClientEventListener

回到一开始的ShenyuSpringMvcClientConfiguration配置类：

/*** shenyu 客户端http注册配置类*/
@Configuration
// shenyu客户端通用配置类
@ImportAutoConfiguration(ShenyuClientCommonBeanConfiguration.class)
@ConditionalOnProperty(value = "shenyu.register.enabled", matchIfMissing = true, havingValue = "true")
public class ShenyuSpringMvcClientConfiguration {static {VersionUtils.checkDuplicate(ShenyuSpringMvcClientConfiguration.class);}/**** 监听并处理http元数据和URI信息的注册** @param clientConfig                   客户端注册配置* @param shenyuClientRegisterRepository 客户端注册类*/@Bean@ConditionalOnMissingBean(ClientRegisterConfiguration.class)// 这里的两个参数是由ShenyuClientCommonBeanConfiguration导入的public SpringMvcClientEventListener springHttpClientEventListener(final ShenyuClientConfig clientConfig,final ShenyuClientRegisterRepository shenyuClientRegisterRepository) {return new SpringMvcClientEventListener(clientConfig.getClient().get(RpcTypeEnum.HTTP.getName()), shenyuClientRegisterRepository);}
}

创建了SpringMvcClientEventListener，负责客户端 元数据 和 URI 数据的构建和注册。SpringMvcClientEventListener继承了AbstractContextRefreshedEventListener，而AbstractContextRefreshedEventListener是一个抽象类，它实现了ApplicationListener接口，并重写了onApplicationEvent()方法，当有Spring事件发生后，该方法会执行。每一种后端服务RPC调用协议都对应了一个监听类。

public class SpringMvcClientEventListener extends AbstractContextRefreshedEventListener<Object, ShenyuSpringMvcClient> {public SpringMvcClientEventListener(final PropertiesConfig clientConfig,final ShenyuClientRegisterRepository shenyuClientRegisterRepository) {super(clientConfig, shenyuClientRegisterRepository);// client配置Properties props = clientConfig.getProps();// 是否是全部接口都注册this.isFull = Boolean.parseBoolean(props.getProperty(ShenyuClientConstants.IS_FULL, Boolean.FALSE.toString()));// http协议this.protocol = props.getProperty(ShenyuClientConstants.PROTOCOL, ShenyuClientConstants.HTTP);this.addPrefixed = Boolean.parseBoolean(props.getProperty(ShenyuClientConstants.ADD_PREFIXED,Boolean.FALSE.toString()));mappingAnnotation.add(ShenyuSpringMvcClient.class);mappingAnnotation.add(RequestMapping.class);}// ...}

SpringMvcClientEventListener的构造函数主要就是调用父类AbstractContextRefreshedEventListener的构造函数，传入客户端配置和客户端注册类，客户端配置指shenyu.client.http下的配置：

shenyu:client:http:props:contextPath: /httpappName: http-appNameport: 8189isFull: false

public abstract class AbstractContextRefreshedEventListener<T, A extends Annotation> implements ApplicationListener<ContextRefreshedEvent> {protected static final String PATH_SEPARATOR = "/";// Disruptor 发布器private final ShenyuClientRegisterEventPublisher publisher = ShenyuClientRegisterEventPublisher.getInstance();// ...public AbstractContextRefreshedEventListener(final PropertiesConfig clientConfig,final ShenyuClientRegisterRepository shenyuClientRegisterRepository) {// 读取 shenyu.client.http 配置信息Properties props = clientConfig.getProps();this.appName = props.getProperty(ShenyuClientConstants.APP_NAME);this.contextPath = Optional.ofNullable(props.getProperty(ShenyuClientConstants.CONTEXT_PATH)).map(UriUtils::repairData).orElse("");if (StringUtils.isBlank(appName) && StringUtils.isBlank(contextPath)) {String errorMsg = "client register param must config the appName or contextPath";LOG.error(errorMsg);throw new ShenyuClientIllegalArgumentException(errorMsg);}this.ipAndPort = props.getProperty(ShenyuClientConstants.IP_PORT);this.host = props.getProperty(ShenyuClientConstants.HOST);this.port = props.getProperty(ShenyuClientConstants.PORT);// 开始事件发布，启动 Disruptorpublisher.start(shenyuClientRegisterRepository);}   }

取出相关配置信息后，就启动 Disruptor 队列，ShenyuClientRegisterEventPublisher可以看作是一个生产者，用来向队列发送数据，

public class ShenyuClientRegisterEventPublisher {private static final ShenyuClientRegisterEventPublisher INSTANCE = new ShenyuClientRegisterEventPublisher();private DisruptorProviderManage<DataTypeParent> providerManage;public static ShenyuClientRegisterEventPublisher getInstance() {return INSTANCE;}/*** Start.** @param shenyuClientRegisterRepository shenyuClientRegisterRepository*/public void start(final ShenyuClientRegisterRepository shenyuClientRegisterRepository) {// 注册任务工厂类，用于创建注册的任务，客户端使用的是RegisterClientExecutorFactory， // 而在服务端（shenyu-admin）用于处理注册任务的是RegisterServerConsumerExecutor，// 都是用于消费Disruptor数据的任务RegisterClientExecutorFactory factory = new RegisterClientExecutorFactory();// 添加元数据订阅器factory.addSubscribers(new ShenyuClientMetadataExecutorSubscriber(shenyuClientRegisterRepository));// 添加URI订阅器factory.addSubscribers(new ShenyuClientURIExecutorSubscriber(shenyuClientRegisterRepository));// 添加ApiDoc订阅器factory.addSubscribers(new ShenyuClientApiDocExecutorSubscriber(shenyuClientRegisterRepository));providerManage = new DisruptorProviderManage<>(factory);// 启动Disruptor队列，并创建消费者providerManage.startup();}/*** 发布事件，向Disruptor队列发数据** @param data the data*/public void publishEvent(final DataTypeParent data) {DisruptorProvider<DataTypeParent> provider = providerManage.getProvider();provider.onData(data);}
}

start方法主要是为队列添加订阅器，会由消费者接收到信息后调用这些订阅器。然后启动启动Disruptor队列，并创建消费者。

public class DisruptorProviderManage<T> {public void startup() {this.startup(false);}public void startup(final boolean isOrderly) {OrderlyExecutor executor = new OrderlyExecutor(isOrderly, consumerSize, consumerSize, 0, TimeUnit.MILLISECONDS,new LinkedBlockingQueue<>(),DisruptorThreadFactory.create("shenyu_disruptor_consumer_", false), new ThreadPoolExecutor.AbortPolicy());int newConsumerSize = this.consumerSize;EventFactory<DataEvent<T>> eventFactory;if (isOrderly) {newConsumerSize = 1;eventFactory = new OrderlyDisruptorEventFactory<>();} else {eventFactory = new DisruptorEventFactory<>();}Disruptor<DataEvent<T>> disruptor = new Disruptor<>(eventFactory,size,DisruptorThreadFactory.create("shenyu_disruptor_provider_" + consumerFactory.fixName(), false),ProducerType.MULTI,new BlockingWaitStrategy());// 创建消费者@SuppressWarnings("all")QueueConsumer<T>[] consumers = new QueueConsumer[newConsumerSize];for (int i = 0; i < newConsumerSize; i++) {consumers[i] = new QueueConsumer<>(executor, consumerFactory);}// 设置消费者disruptor.handleEventsWithWorkerPool(consumers);disruptor.setDefaultExceptionHandler(new IgnoreExceptionHandler());// 真正调用disruptor的api启动disruptor.start();RingBuffer<DataEvent<T>> ringBuffer = disruptor.getRingBuffer();// disruptor的生产者provider = new DisruptorProvider<>(ringBuffer, disruptor, isOrderly);}  }

这里就是准备Disruptor队列的一些逻辑，就不细讲了，其中QueueConsumer是Disruptor的消费者，后面就是由它接收数据。

1.2、扫描注解，注册元数据和URI

上面说到SpringMvcClientEventListener继承了AbstractContextRefreshedEventListener，而AbstractContextRefreshedEventListener实现了ApplicationListener接口，并重写了onApplicationEvent()方法，当有Spring事件发生后，该方法会执行。

// 当有上下文刷新事件ContextRefreshedEvent发生时，该方法会执行，算是客户端的执行入口吧
@Override
public void onApplicationEvent(@NonNull final ContextRefreshedEvent event) {context = event.getApplicationContext();// 获取客户端的接口类，比如http就是Controller类，dubbo就是@DubboService类，由子类实现Map<String, T> beans = getBeans(context);if (MapUtils.isEmpty(beans)) {return;}// 保证只注册一次if (!registered.compareAndSet(false, true)) {return;}// 构建URI并写入Disruptor，由子类实现publisher.publishEvent(buildURIRegisterDTO(context, beans));// 构建元数据并写入Disruptorbeans.forEach(this::handle);Map<String, Object> apiModules = context.getBeansWithAnnotation(ApiModule.class);apiModules.forEach((k, v) -> handleApiDoc(v, beans));
}

获取客户端服务的接口类，由具体的子类实现，http就是Controller类，这里对应的子类就是SpringMvcClientEventListener

@Override
protected Map<String, Object> getBeans(final ApplicationContext context) {// Filter outif (Boolean.TRUE.equals(isFull)) {// isFull=true，表示代理整个服务，就不需要注解扫描了，// 直接构建元数据和URI，写入DisruptorgetPublisher().publishEvent(MetaDataRegisterDTO.builder().contextPath(getContextPath()).addPrefixed(addPrefixed).appName(getAppName()).path(PathUtils.decoratorPathWithSlash(getContextPath())).rpcType(RpcTypeEnum.HTTP.getName()).enabled(true).ruleName(getContextPath()).build());LOG.info("init spring mvc client success with isFull mode");// 构建URIpublisher.publishEvent(buildURIRegisterDTO(context, Collections.emptyMap()));return Collections.emptyMap();}// 否则获取@Controller注解的beanreturn context.getBeansWithAnnotation(Controller.class);
}

这里会判断配置文件中的shenyu.client.http.props.isFull，如果是true，则直接构建一个元数据和URI，写入到Disruptor中，然后返回一个空集合，后续的逻辑就没执行了。如果是false，则从spring容器中获取带@Controller注解的bean返回。

1.2.1、构建URI并写入Disruptor

构建一个URI数据写入到Disruptor，这个也是由子类实现的：

// 构建URI
@Override
protected URIRegisterDTO buildURIRegisterDTO(final ApplicationContext context,final Map<String, Object> beans) {try {return URIRegisterDTO.builder().contextPath(getContextPath()) // shneyu得contextPath.appName(getAppName()) // appName.protocol(protocol) // 服务协议.host(super.getHost()) // 服务host.port(Integer.valueOf(getPort())) // 服务端口.rpcType(RpcTypeEnum.HTTP.getName()) // rpc类型.eventType(EventType.REGISTER) // 事件类型.build();} catch (ShenyuException e) {throw new ShenyuException(e.getMessage() + "please config ${shenyu.client.http.props.port} in xml/yml !");}
}

可以看出来URI跟接口类没有关系，一个后端服务实例生成一个URI。

1.2.2、构建元数据并写入Disruptor

之后遍历每个接口构建元数据beans.forEach(this::handle)

/*** 构建元数据并写入Disruptor*/
protected void handle(final String beanName, final T bean) {Class<?> clazz = getCorrectedClass(bean);// 获取当前bean的对应shenyu客户端的注解，比如http是@ShenyuSpringMvcClient， // dubbo是@ShenyuDubboClientfinal A beanShenyuClient = AnnotatedElementUtils.findMergedAnnotation(clazz, getAnnotationType());// 获取bean对应的path（类上注解的路径），由子类实现final String superPath = buildApiSuperPath(clazz, beanShenyuClient);// 如果有shenyu客户端注解并且path中包含*，则表示要注册整个类的方法，只需要构建一个类元数据if (Objects.nonNull(beanShenyuClient) && superPath.contains("*")) {// 由具体的子类构建类元数据写入DisruptorhandleClass(clazz, bean, beanShenyuClient, superPath);return;}// 类上没有shenyu客户端注解（类上没有注解，但方法上有注解，也是可以注册的），// 或者有注解但是path没有包含*，则就要遍历每个方法，为每个需要注册的方法构建方法元数据final Method[] methods = ReflectionUtils.getUniqueDeclaredMethods(clazz);for (Method method : methods) {// 由具体子类构建方法元数据写入Disruptor，并将每个method对应的元数据对象缓存在当前类里handleMethod(bean, clazz, beanShenyuClient, method, superPath);}
}protected void handleClass(final Class<?> clazz,final T bean,@NonNull final A beanShenyuClient,final String superPath) {publisher.publishEvent(buildMetaDataDTO(bean, beanShenyuClient, pathJoin(contextPath, superPath), clazz, null));
}protected void handleMethod(final T bean,final Class<?> clazz,@Nullable final A beanShenyuClient,final Method method,final String superPath) {// 如果方法上有Shenyu客户端注解，就表示该方法需要注册A methodShenyuClient = AnnotatedElementUtils.findMergedAnnotation(method, getAnnotationType());if (Objects.nonNull(methodShenyuClient)) {final MetaDataRegisterDTO metaData = buildMetaDataDTO(bean, methodShenyuClient,buildApiPath(method, superPath, methodShenyuClient), clazz, method);publisher.publishEvent(metaData);metaDataMap.put(method, metaData);}
}

// 获取接口对应路径，如果shenyu注解上没有，就用@RequestMapping上的路径，
// 但是这个只支持第一个路径
@Override
protected String buildApiSuperPath(final Class<?> clazz, @Nullable final ShenyuSpringMvcClient beanShenyuClient) {if (Objects.nonNull(beanShenyuClient) && StringUtils.isNotBlank(beanShenyuClient.path())) {return beanShenyuClient.path();}RequestMapping requestMapping = AnnotationUtils.findAnnotation(clazz, RequestMapping.class);// Only the first path is supported temporarilyif (Objects.nonNull(requestMapping) && ArrayUtils.isNotEmpty(requestMapping.path()) && StringUtils.isNotBlank(requestMapping.path()[0])) {return requestMapping.path()[0];}return "";
}// springmvc接口上需要有 ShenyuSpringMvcClient 注解，
// 并且包含RequestMapping注解（表示是一个接口），才进行注册
protected void handleMethod(final Object bean, final Class<?> clazz,@Nullable final ShenyuSpringMvcClient beanShenyuClient,final Method method, final String superPath) {final RequestMapping requestMapping = AnnotatedElementUtils.findMergedAnnotation(method, RequestMapping.class);ShenyuSpringMvcClient methodShenyuClient = AnnotatedElementUtils.findMergedAnnotation(method, ShenyuSpringMvcClient.class);methodShenyuClient = Objects.isNull(methodShenyuClient) ? beanShenyuClient : methodShenyuClient;// 如果有 ShenyuSpringMvcClient 注解并且包含RequestMapping注解（表示是一个接口），则进行注册if (Objects.nonNull(methodShenyuClient) && Objects.nonNull(requestMapping)) {// 构建元数据final MetaDataRegisterDTO metaData = buildMetaDataDTO(bean, methodShenyuClient,// 构建path = contextPath + 类上的路径 + 方法上的路径                                        buildApiPath(method, superPath, methodShenyuClient), clazz, method);// 发布元数据getPublisher().publishEvent(metaData);getMetaDataMap().put(method, metaData);}
}// path = contextPath + 类上的路径 + 方法上的路径，
// 如果@ShenyuSpringMvcClient注解上的路径不为空，则方法上的路径=@ShenyuSpringMvcClient上的value，
// 否则，方法上的路径=@RequestMapping上的value
@Override
protected String buildApiPath(final Method method, final String superPath,@NonNull final ShenyuSpringMvcClient methodShenyuClient) {String contextPath = getContextPath();if (StringUtils.isNotBlank(methodShenyuClient.path())) {return pathJoin(contextPath, superPath, methodShenyuClient.path());}final String path = getPathByMethod(method);if (StringUtils.isNotBlank(path)) {return pathJoin(contextPath, superPath, path);}return pathJoin(contextPath, superPath);
}

1.2.3、Disruptor消费数据并向shenyu-admin注册数据

上面启动Disruptor的时候说到QueueConsumer实现了WorkHandler接口，是Disruptor的消费者，消费逻辑就在它的onEvent方法中：

public class QueueConsumer<T> implements WorkHandler<DataEvent<T>> {private final OrderlyExecutor executor;private final QueueConsumerFactory<T> factory;public QueueConsumer(final OrderlyExecutor executor, final QueueConsumerFactory<T> factory) {this.executor = executor;this.factory = factory;}@Overridepublic void onEvent(final DataEvent<T> t) {if (Objects.nonNull(t)) {// 根据事件类型使用不同的线程池ThreadPoolExecutor executor = orderly(t);// 通过工厂创建队列消费任务 RegisterClientConsumerExecutorQueueConsumerExecutor<T> queueConsumerExecutor = factory.create();// 为消费任务设置数据queueConsumerExecutor.setData(t.getData());t.setData(null);// 放在线程池中执行 消费任务executor.execute(queueConsumerExecutor);}}// ...
}

QueueConsumerExecutor是实现了Runnable的消费任务，它有两个实现：

• RegisterClientConsumerExecutor：客户端消费者任务
• RegisterServerConsumerExecutor：服务端消费者任务

从名字也可以看出，RegisterClientConsumerExecutor负责处理客户端任务，shenyu客户端将元数据和URI写入disruptor后由这个消费者任务来消费数据，执行实际向注册中心注册的操作。RegisterServerConsumerExecutor负责处理服务端（shenyu-admin）任务，服务端从注册中心监听到元数据和URI后写入disruptor，然后由RegisterServerConsumerExecutor任务来消费数据，处理数据入库操作和发布事件。
RegisterClientConsumerExecutor的消费逻辑：

public final class RegisterClientConsumerExecutor<T extends DataTypeParent> extends QueueConsumerExecutor<T> {private final Map<DataType, ExecutorTypeSubscriber<T>> subscribers;private RegisterClientConsumerExecutor(final Map<DataType, ExecutorTypeSubscriber<T>> executorSubscriberMap) {this.subscribers = new EnumMap<>(executorSubscriberMap);}@Overridepublic void run() {// 获取数据final T data = getData();// 根据数据类型获取对应的处理器进行处理，即在disruptor启动的时候添加的订阅器subscribers.get(data.getType()).executor(Lists.newArrayList(data));}// ... 
}

根据不同的数据类型使用不同的订阅器执行器去执行，这些订阅器是在disruptor启动的时候设置的。目前注册的数据类型有3种，元数据，URI和API文档。

public enum DataType {/*** Meta data data type enum.*/META_DATA,/*** Uri data type enum.*/URI,/*** Api doc type enum.*/API_DOC,
}

所以相对应的订阅器也分为3类，分别处理元数据，URI和API文档。在客户端和服务端分别有两个，所以一共是6个。

元数据处理

public class ShenyuClientMetadataExecutorSubscriber implements ExecutorTypeSubscriber<MetaDataRegisterDTO> {private final ShenyuClientRegisterRepository shenyuClientRegisterRepository;// .../*** 遍历元数据，对数据注册到注册中心*/@Overridepublic void executor(final Collection<MetaDataRegisterDTO> metaDataRegisterDTOList) {for (MetaDataRegisterDTO metaDataRegisterDTO : metaDataRegisterDTOList) {// 调用响应注册中心的客户端注册类注册元数据shenyuClientRegisterRepository.persistInterface(metaDataRegisterDTO);}}
}

遍历数据，然后又将数据委托给ShenyuClientRegisterRepository执行。ShenyuClientRegisterRepository是在一开始读取配置的时候就创建了，是客户端注册类，用来将数据发送到注册中心的类，不同的注册方式有不同的实现类，该示例使用zookeeper方式注册（shenyu.register.registerType=zookeeper）的实现类是ZookeeperClientRegisterRepository。

@Override
public void persistInterface(final MetaDataRegisterDTO metadata) {// 后端服务rpc类型String rpcType = metadata.getRpcType();// contextPath = StringUtils.isEmpty(contextPath) ? appName : contextPathString contextPath = ContextPathUtils.buildRealNode(metadata.getContextPath(), metadata.getAppName());// 注册元数据registerMetadata(rpcType, contextPath, metadata);
}private void registerMetadata(final String rpcType,final String contextPath,final MetaDataRegisterDTO metadata) {// 构建元数据节点名称String metadataNodeName = buildMetadataNodeName(metadata);// 构建元数据的整体父路径 /shenyu/register/metadata/${rpcType}/${contextPath}String metaDataPath = RegisterPathConstants.buildMetaDataParentPath(rpcType, contextPath);// 当前元数据在zookeeper中的实际路径，上面两个拼起来String realNode = RegisterPathConstants.buildRealNode(metaDataPath, metadataNodeName);// 防止同一个元数据添加多次synchronized (metadataSet) {if (metadataSet.contains(realNode)) {return;}metadataSet.add(realNode);}// 使用客户端类往zookeeper添加数据，元数据是永久节点client.createOrUpdate(realNode, metadata, CreateMode.PERSISTENT);LOGGER.info("{} zookeeper client register metadata success: {}", rpcType, metadata);
}

client是shenyu对zookeeper操作接口的封装

public void createOrUpdate(final String key, final Object value, final CreateMode mode) {if (value != null) {// 元数据以json字符串形式存储String val = GsonUtils.getInstance().toJson(value);createOrUpdate(key, val, mode);} else {createOrUpdate(key, "", mode);}
}public void createOrUpdate(final String key, final String value, final CreateMode mode) {String val = StringUtils.isEmpty(value) ? "" : value;try {// 使用Curator的API往zookeeper保存数据client.create().orSetData().creatingParentsIfNeeded().withMode(mode).forPath(key, val.getBytes(StandardCharsets.UTF_8));} catch (Exception e) {throw new ShenyuException(e);}
}

注册方式比较简单，将元数据的json文本设置到zookeeper对应的路径节点中。

URI处理

public class ShenyuClientURIExecutorSubscriber implements ExecutorTypeSubscriber<URIRegisterDTO> {@Overridepublic void executor(final Collection<URIRegisterDTO> dataList) {for (URIRegisterDTO uriRegisterDTO : dataList) {Stopwatch stopwatch = Stopwatch.createStarted();// 这里的逻辑是为了探测客户端是否已经启动while (true) {try (Socket ignored = new Socket(uriRegisterDTO.getHost(), uriRegisterDTO.getPort())) {break;} catch (IOException e) {long sleepTime = 1000;// maybe the port is delay exposedif (stopwatch.elapsed(TimeUnit.SECONDS) > 5) {LOG.error("host:{}, port:{} connection failed, will retry",uriRegisterDTO.getHost(), uriRegisterDTO.getPort());// If the connection fails for a long time, Increase sleep timeif (stopwatch.elapsed(TimeUnit.SECONDS) > 180) {sleepTime = 10000;}}try {TimeUnit.MILLISECONDS.sleep(sleepTime);} catch (InterruptedException ex) {LOG.error("interrupted when sleep", ex);}}}ShenyuClientShutdownHook.delayOtherHooks();// 向注册中心注册URI数据shenyuClientRegisterRepository.persistURI(uriRegisterDTO);// 优雅停机ShutdownHookManager.get().addShutdownHook(new Thread(() -> {final URIRegisterDTO offlineDTO = new URIRegisterDTO();BeanUtils.copyProperties(uriRegisterDTO, offlineDTO);offlineDTO.setEventType(EventType.OFFLINE);shenyuClientRegisterRepository.offline(offlineDTO);}), 2);}}
}

URI注册逻辑跟元数据的一样

@Override
public void persistURI(final URIRegisterDTO registerDTO) {// 后端服务rpc类型String rpcType = registerDTO.getRpcType();// contextPath = StringUtils.isEmpty(contextPath) ? appName : contextPathString contextPath = ContextPathUtils.buildRealNode(registerDTO.getContextPath(), registerDTO.getAppName());// 注册URIregisterURI(rpcType, contextPath, registerDTO);LOGGER.info("{} zookeeper client register uri success: {}", rpcType, registerDTO);
}private synchronized void registerURI(final String rpcType, final String contextPath, final URIRegisterDTO registerDTO) {// uri节点名称 ${ip:port}String uriNodeName = buildURINodeName(registerDTO);// uri父路径 /shenyu/register/uri/{rpcType}/${contextPath}String uriPath = RegisterPathConstants.buildURIParentPath(rpcType, contextPath);// uri的完整路径，上面两个拼起来String realNode = RegisterPathConstants.buildRealNode(uriPath, uriNodeName);// uri节点数据String nodeData = GsonUtils.getInstance().toJson(registerDTO);nodeDataMap.put(realNode, nodeData);// 往zookeeper设置uri数据，uri节点是临时节点client.createOrUpdate(realNode, nodeData, CreateMode.EPHEMERAL);
}

分析到这里就将客户端的注册逻辑分析完了，通过读取自定义的注解信息构造元数据和URI，将数据发到Disruptor队列，然后从队列中消费数据，将数据写到Zookeeper节点中。Zookeeper存储结构如下：

shenyu├──regsiter├    ├──metadata├    ├     ├──${rpcType}├    ├     ├      ├────${contextPath}├    ├     ├               ├──${ruleName} : save metadata data of MetaDataRegisterDTO├    ├──uri├    ├     ├──${rpcType}├    ├     ├      ├────${contextPath}├    ├     ├               ├──${ip:port} : save uri data of URIRegisterDTO├    ├     ├               ├──${ip:port}

2、服务端注册流程

2.1、读取配置

客户端是将数据注册到注册中心上，所以服务端（shenyu-admin）自然也是要从注册中心中监听数据的。注册中心配置类是RegisterCenterConfiguration，我们先看这个配置类：

/*** 注册中心配置类*/
@Configuration
public class RegisterCenterConfiguration {/*** 读取shenyu.register配置*/@Bean@ConfigurationProperties(prefix = "shenyu.register")public ShenyuRegisterCenterConfig shenyuRegisterCenterConfig() {return new ShenyuRegisterCenterConfig();}/*** 创建用于服务端的注册类，从注册中心中监听数据，然后将数据写入Disruptor队列中*/@Bean(destroyMethod = "close")public ShenyuClientServerRegisterRepository shenyuClientServerRegisterRepository(final ShenyuRegisterCenterConfig shenyuRegisterCenterConfig,final List<ShenyuClientRegisterService> shenyuClientRegisterService) {// 从配置中获取注册类型String registerType = shenyuRegisterCenterConfig.getRegisterType();// 根据注册类型通过SPI方式创建对应的ShenyuClientServerRegisterRepositoryShenyuClientServerRegisterRepository registerRepository = ExtensionLoader.getExtensionLoader(ShenyuClientServerRegisterRepository.class).getJoin(registerType);// 创建Disruptor发布者RegisterClientServerDisruptorPublisher publisher = RegisterClientServerDisruptorPublisher.getInstance();// 每种客户端类型（rpc类型）的处理类Map<String, ShenyuClientRegisterService> registerServiceMap = shenyuClientRegisterService.stream().collect(Collectors.toMap(ShenyuClientRegisterService::rpcType, Function.identity()));// 启动Disruptor，添加元数据和URI的订阅器publisher.start(registerServiceMap);// 初始化注册中心registerRepository.init(publisher, shenyuRegisterCenterConfig);return registerRepository;}
}

该配置类创建了2个bean：

• ShenyuRegisterCenterConfig：shenyu-admin注册中心配置，读取shenyu.register属性配置。
• ShenyuClientServerRegisterRepository：服务端注册类，用于从注册中心中监听数据，然后将数据写入Disruptor队列中。

这里的创建Disruptor发布者，启动Disruptor等逻辑跟在客户端那边的一样，只是类是服务端这边的，就不再分析了。

2.1.1、用于监听的ShenyuClientServerRegisterRepository

上面生成的ShenyuClientServerRegisterRepository是用于实现服务端注册的接口，会根据注册中心的配置通过SPI方式创建注册类，每一个注册方式都对应一个实现类。

目前支持7种注册类型：

• Http：ShenyuClientHttpRegistryController
• Apollo：ApolloClientServerRegisterRepository
• Zookeeper：ZookeeperClientServerRegisterRepository
• Etcd：EtcdClientServerRegisterRepository
• Nacos：NacosClientServerRegisterRepository
• Consul：ConsulClientServerRegisterRepository
• Polaris：PolarisClientServerRegisterRepository
  加载类型通过registerType指定，也就是我们在配置文件中指定的类型：

shenyu:register:registerType: zookeeperserverLists: 127.0.0.1:2181

服务端的注册类型必须跟客户端的注册类型一致，这样服务端才可以监听到注册信息。这里要指定的是zookeeper，所以这里创建的就是ZookeeperClientServerRegisterRepository。
初始化ZookeeperClientServerRegisterRepository时会对zookeeper进行监听

@Join
public class ZookeeperClientServerRegisterRepository implements ShenyuClientServerRegisterRepository {private ShenyuClientServerRegisterPublisher publisher;private ZookeeperClient client;@Overridepublic void init(final ShenyuClientServerRegisterPublisher publisher, final ShenyuRegisterCenterConfig config) {this.init(config);this.publisher = publisher;Properties props = config.getProps();int sessionTimeout = Integer.parseInt(props.getProperty("sessionTimeout", "3000"));int connectionTimeout = Integer.parseInt(props.getProperty("connectionTimeout", "3000"));int baseSleepTime = Integer.parseInt(props.getProperty("baseSleepTime", "1000"));int maxRetries = Integer.parseInt(props.getProperty("maxRetries", "3"));int maxSleepTime = Integer.parseInt(props.getProperty("maxSleepTime", String.valueOf(Integer.MAX_VALUE)));ZookeeperConfig zkConfig = new ZookeeperConfig(config.getServerLists());zkConfig.setBaseSleepTimeMilliseconds(baseSleepTime).setMaxRetries(maxRetries).setMaxSleepTimeMilliseconds(maxSleepTime).setSessionTimeoutMilliseconds(sessionTimeout).setConnectionTimeoutMilliseconds(connectionTimeout);String digest = props.getProperty("digest");if (!StringUtils.isEmpty(digest)) {zkConfig.setDigest(digest);}// 创建zookeeper客户端this.client = new ZookeeperClient(zkConfig);// 启动客户端client.start();// 初始化订阅initSubscribe();}private void initSubscribe() {// 订阅元数据节点，由于是按rpc类型分类的，所以需要分别监听这几个rpc节点RpcTypeEnum.acquireSupportMetadatas().forEach(rpcTypeEnum -> subscribeMetaData(rpcTypeEnum.getName()));// 订阅URI节点，由于是按rpc类型分类的，所以需要分别监听这几个rpc节点RpcTypeEnum.acquireSupportURIs().forEach(rpcTypeEnum -> subscribeURI(rpcTypeEnum.getName()));}// 订阅URIprivate void subscribeURI(final String rpcType) {// /shenyu/register/uri/${rpcType}String contextPathParent = RegisterPathConstants.buildURIContextPathParent(rpcType);// 添加监听client.addCache(contextPathParent, new URICacheListener());}// 订阅元数据节点private void subscribeMetaData(final String rpcType) {// /shenyu/register/metadata/${rpcType}String contextPathParent = RegisterPathConstants.buildMetaDataContextPathParent(rpcType);// 添加监听client.addCache(contextPathParent, new MetadataCacheListener());}// ...
}

2.2、注册元数据和URI

2.2.1、监听数据变更并写入Disruptor

前面分析到服务端启动初始化的时候，会对zookeeper节点进行监听，zookeeper节点结构如下：

shenyu├──regsiter├    ├──metadata├    ├     ├──${rpcType}├    ├     ├      ├────${contextPath}├    ├     ├               ├──${ruleName} : save metadata data of MetaDataRegisterDTO├    ├──uri├    ├     ├──${rpcType}├    ├     ├      ├────${contextPath}├    ├     ├               ├──${ip:port} : save uri data of URIRegisterDTO├    ├     ├               ├──${ip:port}

每一个rpcType节点都会由一个监听器，当它下面的节点变更的时候，会接收到变更的信息。

abstract static class AbstractRegisterListener implements TreeCacheListener {@Overridepublic final void childEvent(final CuratorFramework client, final TreeCacheEvent event) {ChildData childData = event.getData();if (null == childData) {return;}// 变更的路径String path = childData.getPath();if (Strings.isNullOrEmpty(path)) {return;}event(event.getType(), path, childData);}protected abstract void event(TreeCacheEvent.Type type, String path, ChildData data);
}// 元数据注册监听
class MetadataCacheListener extends AbstractRegisterListener {@Overridepublic void event(final TreeCacheEvent.Type type, final String path, final ChildData data) {// 如果不是"/shenyu/register"开头的路径，则略过if (!path.contains(RegisterPathConstants.ROOT_PATH)) {return;}Optional.ofNullable(data).ifPresent(e -> {String str = new String(data.getData(), StandardCharsets.UTF_8);// 往disruptor写入元数据publishMetadata(str);LOGGER.info("zookeeper register metadata success: {}", str);});}
}// URI注册和下线监听
class URICacheListener extends AbstractRegisterListener {@Overridepublic void event(final TreeCacheEvent.Type type, final String path, final ChildData data) {// 不是叶子节点，即不是URI节点，则略过if (data.getData() == null || data.getData().length == 0) {return;}// 将节点的数据转为URI对象URIRegisterDTO uriRegisterDTO = GsonUtils.getInstance().fromJson(new String(data.getData()), URIRegisterDTO.class);if (uriRegisterDTO == null) {return;}switch (type) {case NODE_ADDED: // 服务注册uriRegisterDTO.setEventType(EventType.REGISTER);// 发布URIpublishRegisterURI(Arrays.asList(uriRegisterDTO));break;case NODE_REMOVED: // 服务下线uriRegisterDTO.setEventType(EventType.OFFLINE);// 往disruptor写入URIpublishRegisterURI(Arrays.asList(uriRegisterDTO));break;default:break;}}
}

监听到元数据和URI变更后都是直接写入disruptor队列。

2.2.2、Disruptor消费数据并持久化

QueueConsumer实现了WorkHandler接口，是Disruptor的消费者，消费逻辑就在它的onEvent方法中：

public class QueueConsumer<T> implements WorkHandler<DataEvent<T>> {private final OrderlyExecutor executor;private final QueueConsumerFactory<T> factory;/*** Instantiates a new Queue consumer.** @param executor the executor* @param factory  the factory*/public QueueConsumer(final OrderlyExecutor executor, final QueueConsumerFactory<T> factory) {this.executor = executor;this.factory = factory;}@Overridepublic void onEvent(final DataEvent<T> t) {if (Objects.nonNull(t)) {// 根据事件类型使用不同的线程池ThreadPoolExecutor executor = orderly(t);// 通过工厂创建队列消费任务 RegisterServerConsumerExecutorQueueConsumerExecutor<T> queueConsumerExecutor = factory.create();// 为消费任务设置数据queueConsumerExecutor.setData(t.getData());t.setData(null);// 放在线程池中执行 消费任务executor.execute(queueConsumerExecutor);}}// ...
}

分析客户端注册流程的时候说到RegisterServerConsumerExecutor是服务端消费者任务，处理数据入库操作和发布事件。
RegisterServerConsumerExecutor消费逻辑：

public final class RegisterServerConsumerExecutor extends QueueConsumerExecutor<Collection<DataTypeParent>> {// 每种数据类型的订阅器执行器private final Map<DataType, ExecutorSubscriber<DataTypeParent>> subscribers;private RegisterServerConsumerExecutor(final Map<DataType, ExecutorTypeSubscriber<DataTypeParent>> executorSubscriberMap) {this.subscribers = new HashMap<>(executorSubscriberMap);}@Overridepublic void run() {Collection<DataTypeParent> results = getData().stream().filter(this::isValidData).collect(Collectors.toList());if (CollectionUtils.isEmpty(results)) {return;}// 选择对应的数据类型的订阅器执行器去执行selectExecutor(results).executor(results);}private ExecutorSubscriber<DataTypeParent> selectExecutor(final Collection<DataTypeParent> list) {final Optional<DataTypeParent> first = list.stream().findFirst();return subscribers.get(first.orElseThrow(() -> new RuntimeException("the data type is not found")).getType());}// ...
}

根据不同的数据类型使用不同的订阅器执行器去执行，这些订阅器是在disruptor启动的时候设置的。
服务端的订阅器有3个，分别为MetadataExecutorSubscriber，URIRegisterExecutorSubscriber和ApiDocExecutorSubscriber，分别处理元数据，URI和API文档。

元数据的处理

public class MetadataExecutorSubscriber implements ExecutorTypeSubscriber<MetaDataRegisterDTO> {// 每种客户端类型的注册服务private final Map<String, ShenyuClientRegisterService> shenyuClientRegisterService;public MetadataExecutorSubscriber(final Map<String, ShenyuClientRegisterService> shenyuClientRegisterService) {this.shenyuClientRegisterService = shenyuClientRegisterService;}@Overridepublic DataType getType() {return DataType.META_DATA;}@Overridepublic void executor(final Collection<MetaDataRegisterDTO> metaDataRegisterDTOList) {// 遍历元数据metaDataRegisterDTOList.forEach(meta -> {// 根据客户端类型Optional.ofNullable(this.shenyuClientRegisterService.get(meta.getRpcType())).ifPresent(shenyuClientRegisterService -> {// 加锁，保证数据顺序执行，防止并发synchronized (shenyuClientRegisterService) {// 处理数据shenyuClientRegisterService.register(meta);}});});}
}

ShenyuClientRegisterService是注册方法接口，它有多个实现类：

• AbstractContextPathRegisterService：抽象类，处理部分公共逻辑；
• AbstractShenyuClientRegisterServiceImpl：：抽象类，处理部分公共逻辑；
• ShenyuClientRegisterDivideServiceImpl：divide类，处理http注册类型；
• ShenyuClientRegisterDubboServiceImpl：dubbo类，处理dubbo注册类型；
• ShenyuClientRegisterGrpcServiceImpl：gRPC类，处理gRPC注册类型；
• ShenyuClientRegisterBrpcServiceImpl：bRPC类，处理bRPC注册类型；
• ShenyuClientRegisterMotanServiceImpl：Motan类，处理Motan注册类型；
• ShenyuClientRegisterSofaServiceImpl：Sofa类，处理Sofa注册类型；
• ShenyuClientRegisterSpringCloudServiceImpl：SpringCloud类，处理SpringCloud注册类型；
• ShenyuClientRegisterTarsServiceImpl：Tars类，处理Tars注册类型；
• ShenyuClientRegisterWebSocketServiceImpl：Websocket类，处理Websocket注册类型；

每一种rpc类型都对应一个注册处理类，本实例后端服务是http接口，所以是使用ShenyuClientRegisterDivideServiceImpl来处理。

public abstract class AbstractShenyuClientRegisterServiceImpl extends FallbackShenyuClientRegisterService implements ShenyuClientRegisterService {@Resourceprivate ApplicationEventPublisher eventPublisher;// 这几个就是操作数据库的service@Resourceprivate SelectorService selectorService;@Resourceprivate MetaDataService metaDataService;@Resourceprivate RuleService ruleService;@Overridepublic String register(final MetaDataRegisterDTO dto) {// 1、注册选择器（可以认为一个服务就是一个选择器）// 选择器执行逻辑，默认情况是空的，需要在控制台另外手动配置// 子类实现String selectorHandler = selectorHandler(dto);// 持久化选择器并发布选择器变更事件（不存在的时候）ConfigGroupEnum.SELECTOR, DataEventTypeEnum.UPDATEString selectorId = selectorService.registerDefault(dto, PluginNameAdapter.rpcTypeAdapter(rpcType()), selectorHandler);// 2、注册规则（可以认为一个元数据就是一个规则，根据path判断是否同一个）// 规则处理逻辑// 子类实现，，都是直接创建一个各自rpc类型的默认逻辑String ruleHandler = ruleHandler();// 构建规则DTORuleDTO ruleDTO = buildRpcDefaultRuleDTO(selectorId, dto, ruleHandler);// 持久化规则并发布规则变更事件（不存在的时候）ConfigGroupEnum.RULE, DataEventTypeEnum.UPDATEruleService.registerDefault(ruleDTO);// 3、注册元数据，并发布元数据变更事件（已存在，发布元数据更新事件，不存在，发布元数据创建事件）// 子类实现registerMetadata(dto);// 4、注册contextPath（只有http，springCloud，webSocket类型才有）String contextPath = dto.getContextPath();if (StringUtils.isNotEmpty(contextPath)) {registerContextPath(dto);}return ShenyuResultMessage.SUCCESS;}}

整个注册处理逻辑可以分为4步：

1. 注册选择器，构建选择器，默认情况下一个服务就是一个选择器。之后将选择器插入数据库并发布选择器变更事件。

@Override
public String registerDefault(final MetaDataRegisterDTO dto, final String pluginName, final String selectorHandler) {// 以contextPath或appName作为选择器名称String contextPath = ContextPathUtils.buildContextPath(dto.getContextPath(), dto.getAppName());// 根据选择器名和插件名从数据库中查询选择器SelectorDO selectorDO = findByNameAndPluginName(contextPath, pluginName);// 如果还不存在，就创建一个选择器插入数据库if (Objects.isNull(selectorDO)) {// 构建选择器DTOSelectorDTO selectorDTO = SelectorUtil.buildSelectorDTO(contextPath, pluginMapper.selectByName(pluginName).getId());selectorDTO.setHandle(selectorHandler);// 注册选择器并发布事件 ConfigGroupEnum.SELECTOR, DataEventTypeEnum.UPDATEreturn registerDefault(selectorDTO);}return selectorDO.getId();
}

2. 注册规则，可以认为一个元数据就是一个规则，根据path判断是否同一个。

构建规则：

private RuleDTO buildRpcDefaultRuleDTO(final String selectorId, final MetaDataRegisterDTO metaDataDTO, final String ruleHandler) {return buildRuleDTO(selectorId, ruleHandler, metaDataDTO.getRuleName(), metaDataDTO.getPath());
}private RuleDTO buildRuleDTO(final String selectorId, final String ruleHandler, final String ruleName, final String path) {// 构建规则DTORuleDTO ruleDTO = RuleDTO.builder().selectorId(selectorId).name(ruleName).matchMode(MatchModeEnum.AND.getCode()).enabled(Boolean.TRUE).loged(Boolean.TRUE).matchRestful(Boolean.FALSE).sort(1).handle(ruleHandler).build();// 将{xxx}替换成**String conditionPath = this.rewritePath(path);RuleConditionDTO ruleConditionDTO = RuleConditionDTO.builder().paramType(ParamTypeEnum.URI.getName()).paramName("/").paramValue(conditionPath).build();// 设置规则条件if (conditionPath.endsWith(AdminConstants.URI_SLASH_SUFFIX)) {ruleConditionDTO.setOperator(OperatorEnum.STARTS_WITH.getAlias());} else if (conditionPath.endsWith(AdminConstants.URI_SUFFIX)) {ruleConditionDTO.setOperator(OperatorEnum.PATH_PATTERN.getAlias());} else if (conditionPath.indexOf("*") > 1) {ruleConditionDTO.setOperator(OperatorEnum.MATCH.getAlias());} else {ruleConditionDTO.setOperator(OperatorEnum.EQ.getAlias());}ruleDTO.setRuleConditions(Collections.singletonList(ruleConditionDTO));return ruleDTO;
}

保存规则：

@Override
public String registerDefault(final RuleDTO ruleDTO) {// 选择器下已经存在同名的规则，则直接返回，什么也不干if (Objects.nonNull(ruleMapper.findBySelectorIdAndName(ruleDTO.getSelectorId(), ruleDTO.getName()))) {return "";}RuleDO ruleDO = RuleDO.buildRuleDO(ruleDTO);if (StringUtils.isEmpty(ruleDTO.getId())) {// 插入规则ruleMapper.insertSelective(ruleDO);// 插入规则条件addCondition(ruleDO, ruleDTO.getRuleConditions());}// 发布规则变更事件 ConfigGroupEnum.RULE, DataEventTypeEnum.UPDATEruleEventPublisher.onRegister(ruleDO, ruleDTO.getRuleConditions());return ruleDO.getId();
}

具体的规则设计建议去看官方文档。

3. 注册元数据，直接将注册上来的元数据保存

@Override
protected void registerMetadata(final MetaDataRegisterDTO dto) {if (dto.isRegisterMetaData()) {MetaDataService metaDataService = getMetaDataService();// 根据路径查询元数据时候已存在MetaDataDO exist = metaDataService.findByPath(dto.getPath());// 已存在，就更新，发布元数据更新事件，不存在，就插入，发布元数据创建事件（用于同步网关）metaDataService.saveOrUpdateMetaData(exist, dto);}
}

4. 注册ContextPath，只有http，springCloud，webSocket类型才有。处理的逻辑在AbstractContextPathRegisterService中。

public abstract class AbstractContextPathRegisterService extends AbstractShenyuClientRegisterServiceImpl {@Overridepublic void registerContextPath(final MetaDataRegisterDTO dto) {// 持久化contextPath插件下的选择器并发布选择器变更事件String contextPathSelectorId = getSelectorService().registerDefault(dto, PluginEnum.CONTEXT_PATH.getName(), "");// 创建规则处理逻辑ContextMappingRuleHandle handle = new ContextMappingRuleHandle();handle.setContextPath(PathUtils.decoratorContextPath(dto.getContextPath()));handle.setAddPrefixed(dto.getAddPrefixed());// 注册contextPath插件默认的规则，contextPath就是规则名，并发布规则变更事件（用于同步网关）getRuleService().registerDefault(buildContextPathDefaultRuleDTO(contextPathSelectorId, dto, handle.toJson()));}
}

URI的处理
URI数据是由URIRegisterExecutorSubscriber订阅器处理：

public class URIRegisterExecutorSubscriber implements ExecutorTypeSubscriber<URIRegisterDTO> {@Overridepublic void executor(final Collection<URIRegisterDTO> dataList) {if (CollectionUtils.isEmpty(dataList)) {return;}// 根据rpc类型分类final Map<String, List<URIRegisterDTO>> groupByRpcType = dataList.stream().filter(data -> StringUtils.isNotBlank(data.getRpcType())).collect(Collectors.groupingBy(URIRegisterDTO::getRpcType));for (Map.Entry<String, List<URIRegisterDTO>> entry : groupByRpcType.entrySet()) {// 根据不同rpc类型使用对应的shenyuClientRegisterService处理final String rpcType = entry.getKey();Optional.ofNullable(shenyuClientRegisterService.get(rpcType)).ifPresent(service -> {final List<URIRegisterDTO> list = entry.getValue();// 再以contextPath/appName分类Map<String, List<URIRegisterDTO>> listMap = buildData(list);listMap.forEach((selectorName, uriList) -> {final List<URIRegisterDTO> register = new LinkedList<>();final List<URIRegisterDTO> offline = new LinkedList<>();for (URIRegisterDTO d : uriList) {final EventType eventType = d.getEventType();// 判断是注册类型还是下线类型（服务实例启动和下线）if (Objects.isNull(eventType) || EventType.REGISTER.equals(eventType)) {// eventType is null, should be old versionsregister.add(d);} else if (EventType.OFFLINE.equals(eventType)) {offline.add(d);}}if (CollectionUtils.isNotEmpty(register)) {// 注册URIservice.registerURI(selectorName, register);}if (CollectionUtils.isNotEmpty(offline)) {// 下线URIservice.offline(selectorName, offline);}});});}}private Map<String, List<URIRegisterDTO>> buildData(final Collection<URIRegisterDTO> dataList) {Map<String, List<URIRegisterDTO>> resultMap = new HashMap<>(8);for (URIRegisterDTO dto : dataList) {String contextPath = dto.getContextPath();String key = StringUtils.isNotEmpty(contextPath) ? contextPath : dto.getAppName();if (StringUtils.isNotEmpty(key)) {if (resultMap.containsKey(key)) {List<URIRegisterDTO> existList = resultMap.get(key);existList.add(dto);resultMap.put(key, existList);} else {resultMap.put(key, Lists.newArrayList(dto));}}}return resultMap;}
}

调到FallbackShenyuClientRegisterService的registerURI()方法

@Override
public String registerURI(final String selectorName, final List<URIRegisterDTO> uriList) {String result;String key = key(selectorName);try {this.removeFallBack(key);// 注册uriresult = this.doRegisterURI(selectorName, uriList);logger.info("Register success: {},{}", selectorName, uriList);} catch (Exception ex) {logger.warn("Register exception: cause:{}", ex.getMessage());result = "";this.addFallback(key, new FallbackHolder(selectorName, uriList));}return result;
}
FallbackShenyuClientRegisterService是用来异常处理的，然后调用doRegisterURI()做真正处理。
@Override
public String doRegisterURI(final String selectorName, final List<URIRegisterDTO> uriList) {if (CollectionUtils.isEmpty(uriList)) {return "";}// 查询对应的选择器SelectorDO selectorDO = selectorService.findByNameAndPluginName(selectorName, PluginNameAdapter.rpcTypeAdapter(rpcType()));if (Objects.isNull(selectorDO)) {throw new ShenyuException("doRegister Failed to execute,wait to retry.");}// 过滤port或host为空的URIList<URIRegisterDTO> validUriList = uriList.stream().filter(dto -> Objects.nonNull(dto.getPort()) && StringUtils.isNotBlank(dto.getHost())).collect(Collectors.toList());// 由URI构建处理选择器中的handler信息，更新选择器中的handler// 应该就是相当于添加上服务实例信息String handler = buildHandle(validUriList, selectorDO);if (handler != null) {selectorDO.setHandle(handler);SelectorData selectorData = selectorService.buildByName(selectorName, PluginNameAdapter.rpcTypeAdapter(rpcType()));selectorData.setHandle(handler);// 更新数据库selectorService.updateSelective(selectorDO);// 发布选择器变更事件（用于同步给网关）eventPublisher.publishEvent(new DataChangedEvent(ConfigGroupEnum.SELECTOR, DataEventTypeEnum.UPDATE, Collections.singletonList(selectorData)));}return ShenyuResultMessage.SUCCESS;
}

总结就是admin拿到URI数据后，更新选择器中的handler信息，然后写入到数据库，最后发布事件。
更新的就是这里的信息：

至此，服务端注册流程也就分析完了，主要通过对外提供的接口，接受客户端的注册信息，然后写入到Disruptor队列，再从中消费数据，根据接收到的元数据和URI数据更新admin的选择器、规则、元数据和选择器的handler。

参考资料：
官方博客