NamingClientProxyDelegate 实现
继续追踪 NamingClientProxyDelegate#registerService 方法的具体实现，代码如下：
public void registerService(String serviceName, String groupName, Instance instance) throws NacosException { getExecuteClientProxy(instance).registerService(serviceName, groupName, instance); }
真正调用注册服务方并不是代理实现类，而是通过当前实例是否为瞬时对象，来选择对应的客户端代理进行请求：
private NamingClientProxy getExecuteClientProxy(Instance instance) { return instance.isEphemeral() ? grpcClientProxy : httpClientProxy; }
如果当前实例为瞬时对象，则采用 gRPC 协议(NamingGrpcClientProxy)进行请求，否则采用(NamingHttpClientProxy)进行请求
private boolean ephemeral = true;
默认为瞬时对象，也就是说，2.0 版本默认采用了 gRPC 协议与 Nacos 服务进行交互
NamingGrpcClientProxy 实现
主要关注一下 registerService 方法的实现，主要作了以下两件事情：
1、缓存当前注册的实例信息用于恢复，缓存的数据结构为 ConcurrentMap<String, InstanceRedoData>：Key->groupName@@serviceName，value->前面封装的实例信息「Instance、groupName、serviceName」
2、另外一件事情就是封装了具体的参数，基于 gRPC 进行服务的调用和结果的处理
public void registerService(String serviceName, String groupName, Instance instance) throws NacosException { NAMING_LOGGER.info("[REGISTER-SERVICE] {} registering service {} with instance {}", namespaceId, serviceName, instance); // 缓存数据 redoService.cacheInstanceForRedo(serviceName, groupName, instance); // 基于 gRPC 进行服务的调用 doRegisterService(serviceName, groupName, instance); } public void doRegisterService(String serviceName, String groupName, Instance instance) throws NacosException { // 封装好请求信息 InstanceRequest request = new InstanceRequest(namespaceId, serviceName, groupName, NamingRemoteConstants.REGISTER_INSTANCE, instance); // 发送请求服务端进行注册 requestToServer(request, Response.class); // 标识该服务已被注册 redoService.instanceRegistered(serviceName, groupName); }
Nacos 入口源码流程图
Nacos 客户端实例注册源码案例分析
实际上我们在真实的生产的环境中，若让某个服务注册到 Nacos 中，首先需要引入依赖：
<dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency>
在引入这个依赖之后，找到 spring-boot 自动装配文件：META-INF/spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\ com.alibaba.cloud.nacos.discovery.NacosDiscoveryAutoConfiguration,\ com.alibaba.cloud.nacos.ribbon.RibbonNacosAutoConfiguration,\ com.alibaba.cloud.nacos.endpoint.NacosDiscoveryEndpointAutoConfiguration,\ com.alibaba.cloud.nacos.registry.NacosServiceRegistryAutoConfiguration,\ com.alibaba.cloud.nacos.discovery.NacosDiscoveryClientConfiguration,\ com.alibaba.cloud.nacos.discovery.reactive.NacosReactiveDiscoveryClientConfiguration,\ com.alibaba.cloud.nacos.discovery.configclient.NacosConfigServerAutoConfiguration,\ com.alibaba.cloud.nacos.NacosServiceAutoConfiguration org.springframework.cloud.bootstrap.BootstrapConfiguration=\ com.alibaba.cloud.nacos.discovery.configclient.NacosDiscoveryClientConfigServiceBootstrapConfiguration org.springframework.context.ApplicationListener=\ com.alibaba.cloud.nacos.discovery.logging.NacosLoggingListener
然后再 spring-boot 自动装配的功能，自动装配的源码实现可以看博主博客：SpringBoot 自动装配流程及源码剖析
首先找到加载 EnbaleAutoConfiguration 对应的类，然后在这里我们就能看见很多 Nacos 相关的内容，一般这种文件都会找 Auto 关键字的文件来进行查看，然后我们要现在要了解的是客户端注册，所以我们应该要找的是：NacosServiceRegistryAutoConfiguration
@Configuration(proxyBeanMethods = false) @EnableConfigurationProperties @ConditionalOnNacosDiscoveryEnabled @ConditionalOnProperty(value = {"spring.cloud.service-registry.auto-registration.enabled"},matchIfMissing = true) @AutoConfigureAfter({AutoServiceRegistrationConfiguration.class, AutoServiceRegistrationAutoConfiguration.class, NacosDiscoveryAutoConfiguration.class}) public class NacosServiceRegistryAutoConfiguration { public NacosServiceRegistryAutoConfiguration() { } @Bean public NacosServiceRegistry nacosServiceRegistry(NacosServiceManager nacosServiceManager, NacosDiscoveryProperties nacosDiscoveryProperties) { return new NacosServiceRegistry(nacosServiceManager, nacosDiscoveryProperties); } @Bean @ConditionalOnBean({AutoServiceRegistrationProperties.class}) public NacosRegistration nacosRegistration(ObjectProvider<List<NacosRegistrationCustomizer>> registrationCustomizers, NacosDiscoveryProperties nacosDiscoveryProperties, ApplicationContext context) { return new NacosRegistration((List)registrationCustomizers.getIfAvailable(), nacosDiscoveryProperties, context); } @Bean @ConditionalOnBean({AutoServiceRegistrationProperties.class}) public NacosAutoServiceRegistration nacosAutoServiceRegistration(NacosServiceRegistry registry, AutoServiceRegistrationProperties autoServiceRegistrationProperties, NacosRegistration registration) { return new NacosAutoServiceRegistration(registry, autoServiceRegistrationProperties, registration); } }
在此类中有很多的 Bean 组件，这些都是 spring 容器启动时自动进行注入的，一般情况下我们可能会看每一个 Bean 组件初始化时具体作了什么，但是实际上这里最核心的是 NacosAutoServiceRegistration 类，注入它时还需要三个参数，这三个参数会提前被加载，尤其是 NacosServiceRegistry 这个参数后续中也会用到
NacosAutoServiceRegistration
通过以上的类图可以看出，NacosAutoServiceRegistration 继承自 AbstractAutoServiceRegistration，而这个类型又实现了 ApplicationListener 接口，一般只要实现了 ApplicationListener 接口的，只需要关注它的 onApplicationEvent 方法的实现逻辑，它会帮我们完成一些初始化加载的工作，该方法是在项目启动时-容器进行初始化时进行调用的
public void onApplicationEvent(WebServerInitializedEvent event) { this.bind(event); } @Deprecated public void bind(WebServerInitializedEvent event) { ApplicationContext context = event.getApplicationContext(); if (!(context instanceof ConfigurableWebServerApplicationContext) || !"management".equals(((ConfigurableWebServerApplicationContext)context).getServerNamespace())) { this.port.compareAndSet(0, event.getWebServer().getPort()); this.start(); } }
最终在 start 方法中调用 register 方法进行服务注册
public void start() { if (!this.isEnabled()) { if (logger.isDebugEnabled()) { logger.debug("Discovery Lifecycle disabled. Not starting"); } } else { if (!this.running.get()) { this.context.publishEvent(new InstancePreRegisteredEvent(this, this.getRegistration())); this.register(); if (this.shouldRegisterManagement()) { this.registerManagement(); } this.context.publishEvent(new InstanceRegisteredEvent(this, this.getConfiguration())); this.running.compareAndSet(false, true); } } }
ServiceRegistry#register
分析到这里，可以得知真实的服务注册的入口和具体调用那个方法来注册
protected void register() { this.serviceRegistry.register(this.getRegistration()); }
但 serviceRegistry 实际上是一个接口，它的具体实现类是 NacosServiceRegistry，到这里就与之前分析到的源码连接在一起了，因为在这里调用了之前讲过的 registerInstance 实例注册方法，查看该类下的 register 方法🥱
public void register(Registration registration) { if (StringUtils.isEmpty(registration.getServiceId())) { log.warn("No service to register for nacos client..."); } else { NamingService namingService = this.namingService(); String serviceId = registration.getServiceId(); String group = this.nacosDiscoveryProperties.getGroup(); // 构建 Instance 实例 Instance instance = this.getNacosInstanceFromRegistration(registration); try { // 向服务端注册此客户端 namingService.registerInstance(serviceId, group, instance); log.info("nacos registry, {} {} {}:{} register finished", new Object[]{group, serviceId, instance.getIp(), instance.getPort()}); } catch (Exception var7) { if (this.nacosDiscoveryProperties.isFailFast()) { log.error("nacos registry, {} register failed...{},", new Object[]{serviceId, registration.toString(), var7}); ReflectionUtils.rethrowRuntimeException(var7); } else { log.warn("Failfast is false. {} register failed...{},", new Object[]{serviceId, registration.toString(), var7}); } } } }
接下来就是从已经分析过的链路进行调用了，如下：
NamingClientProxyDelegate#registerService—>NamingGrpcClientProxy#registerService
此段源码在标题「Nacos 客户端服务注册源码入口分析」分析过，在这不作过多阐述
NamingGrpcClientProxy#requestToServer
发送请求服务端进行注册实例，在此处会涉及到 rpcClient#request 方法调用
private <T extends Response> T requestToServer(AbstractNamingRequest request, Class<T> responseClass) throws NacosException { try { request.putAllHeader(this.getSecurityHeaders(request.getNamespace(), request.getGroupName(), request.getServiceName())); Response response = this.requestTimeout < 0L ? this.rpcClient.request(request) : this.rpcClient.request(request, this.requestTimeout); if (ResponseCode.SUCCESS.getCode() != response.getResultCode()) { throw new NacosException(response.getErrorCode(), response.getMessage()); } if (responseClass.isAssignableFrom(response.getClass())) { return response; } LogUtils.NAMING_LOGGER.error("Server return unexpected response '{}', expected response should be '{}'", response.getClass().getName(), responseClass.getName()); } catch (Exception var4) { throw new NacosException(500, "Request nacos server failed: ", var4); } throw new NacosException(500, "Server return invalid response"); }
此 RpcClient 对象是在 NamingGrpcClientProxy 构造函数中进行初始化的，随即会调用其下 start 方法启动，在里面会调用 connectToServer(serverInfo) 方法「主要操作：通过地址+端口来初始化 gRPC 连接信息后进行建立连接」
public NamingGrpcClientProxy(String namespaceId, SecurityProxy securityProxy, ServerListFactory serverListFactory, Properties properties, ServiceInfoHolder serviceInfoHolder) throws NacosException { super(securityProxy); this.namespaceId = namespaceId; this.uuid = UUID.randomUUID().toString(); this.requestTimeout = Long.parseLong(properties.getProperty("namingRequestTimeout", "-1")); Map<String, String> labels = new HashMap(); labels.put("source", "sdk"); labels.put("module", "naming"); this.rpcClient = RpcClientFactory.createClient(this.uuid, ConnectionType.GRPC, labels); this.redoService = new NamingGrpcRedoService(this); this.start(serverListFactory, serviceInfoHolder); } private void start(ServerListFactory serverListFactory, ServiceInfoHolder serviceInfoHolder) throws NacosException { this.rpcClient.serverListFactory(serverListFactory); this.rpcClient.registerConnectionListener(this.redoService); this.rpcClient.registerServerRequestHandler(new NamingPushRequestHandler(serviceInfoHolder)); this.rpcClient.start(); NotifyCenter.registerSubscriber(this); }
随即在 requestToServer 方法中调用 rpcClient#request 方法就可以将客户端实例注册进去了！！！
