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实例客户端注册入口
流程图#xff1a; 实际上我们在真实的生产环境中#xff0c;我们要让某一个服务注册到Nacos中#xff0c;我们首先要引入一个依赖#xff1a;
dependencygroupIdcom.alibaba.cloud/groupId 实际上我们在真实的生产环境中我们要让某一个服务注册到Nacos中我们首先要引入一个依赖
dependencygroupIdcom.alibaba.cloud/groupIdartifactIdspring-cloud-starter-alibaba-nacos-discovery/artifactId
/dependency在引入这个依赖以后我们要找到SpringBoot自动装配文件META-INF/spring.factories文件 然后再通过SpingBoot的自动装配首先找到来加载EnableAutoConfiguration对应的类然后这里我们就能看见很多Nacos相关的内容那我们怎么能知道这个服务在注册的时候具体走的时候哪一个其实一般这种文件我们都会找“Auto”关键子的文件来进行查看然后我们现在要了解的是客户端的注册所以我们要找“NacosServiceRegistryAutoConfiguration”。 然后在当前这个类中会有很多的Bean组件这些都是Spring容器启动时候自动注入的一般情况下可能我们会看一下每一个Bean组件初始化具体干了什么但是实际上这里最核心的是“NacosAutoServiceRegistration”
/*** author xiaojing* author a hrefmailto:mercyblitzgmail.comMercy/a*/
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 {Beanpublic NacosServiceRegistry nacosServiceRegistry(NacosDiscoveryProperties nacosDiscoveryProperties) {return new NacosServiceRegistry(nacosDiscoveryProperties);}BeanConditionalOnBean(AutoServiceRegistrationProperties.class)public NacosRegistration nacosRegistration(ObjectProviderListNacosRegistrationCustomizer registrationCustomizers,NacosDiscoveryProperties nacosDiscoveryProperties,ApplicationContext context) {return new NacosRegistration(registrationCustomizers.getIfAvailable(),nacosDiscoveryProperties, context);}BeanConditionalOnBean(AutoServiceRegistrationProperties.class)public NacosAutoServiceRegistration nacosAutoServiceRegistration(NacosServiceRegistry registry,AutoServiceRegistrationProperties autoServiceRegistrationProperties,NacosRegistration registration) {return new NacosAutoServiceRegistration(registry,autoServiceRegistrationProperties, registration);}}NacosAutoServiceRegistration
其实这个类就是注册的核心所以我们来看一下它的继承关系 通过这里我们可以清楚的知道
NacosAutoServiceRegistration继承了AbstractAutoServiceRegistration而这个类型实现了ApplicationListener接口所以我们由此得出一般实现ApplicationListener接口的类型都会实现一个方法onApplicationEvent这个方法会在项目启动的时候触发
public void onApplicationEvent(WebServerInitializedEvent event) {bind(event);
}Deprecated
public void bind(WebServerInitializedEvent event) {ApplicationContext context event.getApplicationContext();if (context instanceof ConfigurableWebServerApplicationContext) {if (management.equals(((ConfigurableWebServerApplicationContext) context).getServerNamespace())) {return;}}this.port.compareAndSet(0, event.getWebServer().getPort());this.start();
}然后在start()方法中调用register()方法来注册服务
public void start() {if (!isEnabled()) {if (logger.isDebugEnabled()) {logger.debug(Discovery Lifecycle disabled. Not starting);}return;}// only initialize if nonSecurePort is greater than 0 and it isnt already running// because of containerPortInitializer belowif (!this.running.get()) {this.context.publishEvent(new InstancePreRegisteredEvent(this, getRegistration()));register();if (shouldRegisterManagement()) {registerManagement();}this.context.publishEvent(new InstanceRegisteredEvent(this, getConfiguration()));this.running.compareAndSet(false, true);}}serviceRegistry.register
分析到这里我们已经知道了真实服务注册的入口和具体调用那个方法来注册那我们再来分析一下register这个方法
protected void register() {this.serviceRegistry.register(getRegistration());
}但是这里要注意serviceRegistry实际上是一个接口所以我们来看一下它的具体实现类NacosServiceRegistry: 找到这个实现类然后我们来查看register方法到这里其实大家应该已经明白了因为这里调用了我们上节课讲过的registerInstance注册实例方法
Override
public void register(Registration registration) {if (StringUtils.isEmpty(registration.getServiceId())) {log.warn(No service to register for nacos client...);return;}NamingService namingService namingService();String serviceId registration.getServiceId();String group nacosDiscoveryProperties.getGroup();//构建instance实例Instance instance getNacosInstanceFromRegistration(registration);try {//向服务端注册此服务namingService.registerInstance(serviceId, group, instance);log.info(nacos registry, {} {} {}:{} register finished, group, serviceId,instance.getIp(), instance.getPort());}catch (Exception e) {log.error(nacos registry, {} register failed...{},, serviceId,registration.toString(), e);// rethrow a RuntimeException if the registration is failed.// issue : https://github.com/alibaba/spring-cloud-alibaba/issues/1132rethrowRuntimeException(e);}
}调用接口
其实到这里大家应该已经明白Nacos客户端的服务注册过程了但是其实再给大家补充一点就是其实注册本身就是访问了Nacos提供的一个接口我们可以在官网上看到 那我们可以通过deBug来看一下在NacosServiceRegistry中的register方法中在注册实例方法中打断点 然后在NamingService的实现类NacosNamingService中registerInstance方法中打断点 然后进入到这个registerService方法中进行查看就会发现这里就会把实例信息放到散列表中然后调用reqApi方法来发送请求访问接口/nacos/v1/ns/instance 总结
