spring-cloud-starter-alibaba-nac

spring-cloud-starter-alibaba-nacos-discovery

查看源码可知，自动将配置以下配置都加载到当前SpringBoot创建并使用的IoC容器
将各个bean注入到容器中，以便于后期完成注册

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

com.alibaba.cloud.nacos.discovery.NacosDiscoveryAutoConfiguration

/**
 * 配置nacos服务发现的自动化配置
 * 注入NacosDiscoveryProperties、NacosServiceDiscovery
 * @author <a href="mailto:echooy.mxq@gmail.com">echooymxq</a>
 **/
@Configuration(proxyBeanMethods = false)
@ConditionalOnDiscoveryEnabled
@ConditionalOnNacosDiscoveryEnabled
public class NacosDiscoveryAutoConfiguration {

    //注入对应的配置项，处理配置项null的数据为""，判断并设置ip，并从环境中覆盖nacos发现配置
    //如果是nacos服务信息发生变化，则发布事件NacosDiscoveryInfoChangedEvent
    @Bean
    @ConditionalOnMissingBean
    public NacosDiscoveryProperties nacosProperties() {
        return new NacosDiscoveryProperties();
    }

    //注入服务发现类
    @Bean
    @ConditionalOnMissingBean
    public NacosServiceDiscovery nacosServiceDiscovery(
            NacosDiscoveryProperties discoveryProperties,
            NacosServiceManager nacosServiceManager) {
        return new NacosServiceDiscovery(discoveryProperties, nacosServiceManager);
    }
}

将NacosDiscoveryProperties、NacosServiceDiscovery注入到容器中，其中nacosServiceDiscovery需要先自动配置NacosServiceAutoConfiguration注入NacosServiceManager再运行

com.alibaba.cloud.nacos.NacosServiceAutoConfiguration

@Configuration(proxyBeanMethods = false)
@ConditionalOnDiscoveryEnabled
@ConditionalOnNacosDiscoveryEnabled
public class NacosServiceAutoConfiguration {

    //注入nacos服务管理，并设置监听事件InstancePreRegisteredEvent，监听服务注册之前的事件发布
    @Bean
    public NacosServiceManager nacosServiceManager() {
        return new NacosServiceManager();
    }

}

注入NacosServiceManager

com.alibaba.cloud.nacos.registry.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 {

    //注入nacos服务注册中心
    @Bean
    public NacosServiceRegistry nacosServiceRegistry(
            NacosDiscoveryProperties nacosDiscoveryProperties) {
        return new NacosServiceRegistry(nacosDiscoveryProperties);
    }

    //注入nacos注册配置，初始化元数据，并且提供自定义元数据的修改方式
    @Bean
    @ConditionalOnBean(AutoServiceRegistrationProperties.class)
    public NacosRegistration nacosRegistration(
            ObjectProvider<List<NacosRegistrationCustomizer>> registrationCustomizers,
            NacosDiscoveryProperties nacosDiscoveryProperties,
            ApplicationContext context) {
        return new NacosRegistration(registrationCustomizers.getIfAvailable(),
                nacosDiscoveryProperties, context);
    }

    //注入nacos自动服务注册类，并监听事件NacosDiscoveryInfoChangedEvent，该事件在NacosDiscoveryProperties中进行的发布配置
    @Bean
    @ConditionalOnBean(AutoServiceRegistrationProperties.class)
    public NacosAutoServiceRegistration nacosAutoServiceRegistration(
            NacosServiceRegistry registry,
            AutoServiceRegistrationProperties autoServiceRegistrationProperties,
            NacosRegistration registration) {
        return new NacosAutoServiceRegistration(registry,
                autoServiceRegistrationProperties, registration);
    }

}

com.alibaba.cloud.nacos.discovery.reactive.NacosReactiveDiscoveryClientConfiguration

/**
 * Nacos反应式发现客户端配置
 **/
@Configuration(proxyBeanMethods = false)
@ConditionalOnDiscoveryEnabled
@ConditionalOnReactiveDiscoveryEnabled
@ConditionalOnNacosDiscoveryEnabled
@AutoConfigureAfter({ NacosDiscoveryAutoConfiguration.class,
        ReactiveCompositeDiscoveryClientAutoConfiguration.class })
@AutoConfigureBefore({ ReactiveCommonsClientAutoConfiguration.class })
public class NacosReactiveDiscoveryClientConfiguration {

    //注入nacos反应式服务发现客户端
    @Bean
    @ConditionalOnMissingBean
    public NacosReactiveDiscoveryClient nacosReactiveDiscoveryClient(
            NacosServiceDiscovery nacosServiceDiscovery) {
        return new NacosReactiveDiscoveryClient(nacosServiceDiscovery);
    }

}

com.alibaba.cloud.nacos.ribbon.RibbonNacosAutoConfiguration

配置ribbon客户端
@Configuration(proxyBeanMethods = false)
@EnableConfigurationProperties
@ConditionalOnBean(SpringClientFactory.class)
@ConditionalOnRibbonNacos
@ConditionalOnNacosDiscoveryEnabled
@AutoConfigureAfter(RibbonAutoConfiguration.class)
@RibbonClients(defaultConfiguration = NacosRibbonClientConfiguration.class)
public class RibbonNacosAutoConfiguration {

}

------------------------------

@Configuration(proxyBeanMethods = false)
@ConditionalOnRibbonNacos
public class NacosRibbonClientConfiguration {

    @Autowired
    private PropertiesFactory propertiesFactory;

    //注入服务列表
    @Bean
    @ConditionalOnMissingBean
    public ServerList<?> ribbonServerList(IClientConfig config,
            NacosDiscoveryProperties nacosDiscoveryProperties) {
        if (this.propertiesFactory.isSet(ServerList.class, config.getClientName())) {
            ServerList serverList = this.propertiesFactory.get(ServerList.class, config,
                    config.getClientName());
            return serverList;
        }
        NacosServerList serverList = new NacosServerList(nacosDiscoveryProperties);
        serverList.initWithNiwsConfig(config);
        return serverList;
    }

    //注入Nacos服务器自检器
    @Bean
    @ConditionalOnMissingBean
    public NacosServerIntrospector nacosServerIntrospector() {
        return new NacosServerIntrospector();
    }

}

由于ribbonNacos需要在RibbonAutoConfiguration配置完成之后才进行自动配置，而RibbonAutoConfiguration又需要在org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration完成配置之后才会进行自动配置，默认不带这eureka相关jar包，所以，在默认情况下，不会进行ribbon

com.alibaba.cloud.nacos.endpoint.NacosDiscoveryEndpointAutoConfiguration

/**
 * The AutoConfiguration class for Nacos Discovery's Endpoints.
 * 暴露nacos服务发现的端点，包括NacosDiscoveryProperties和subscribe
 * @author xiaojing
 * @author <a href="mailto:mercyblitz@gmail.com">Mercy</a>
 */
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(Endpoint.class)
@ConditionalOnNacosDiscoveryEnabled
public class NacosDiscoveryEndpointAutoConfiguration {

    @Bean
    @ConditionalOnMissingBean
    @ConditionalOnAvailableEndpoint
    public NacosDiscoveryEndpoint nacosDiscoveryEndpoint(
            NacosServiceManager nacosServiceManager,
            NacosDiscoveryProperties nacosDiscoveryProperties) {
        return new NacosDiscoveryEndpoint(nacosServiceManager, nacosDiscoveryProperties);
    }

    @Bean
    @ConditionalOnEnabledHealthIndicator("nacos-discovery")
    public HealthIndicator nacosDiscoveryHealthIndicator(
            NacosServiceManager nacosServiceManager,
            NacosDiscoveryProperties nacosDiscoveryProperties) {
        Properties nacosProperties = nacosDiscoveryProperties.getNacosProperties();
        return new NacosDiscoveryHealthIndicator(
                nacosServiceManager.getNamingService(nacosProperties));
    }

}

其中NacosDiscoveryEndpoint通过Endpoint和ReadOperation两个注解将该方法通过JMX自动公开，并且在web应用程序中也通过http get方式公开，通过actuator来暴露对应的端点

com.alibaba.cloud.nacos.discovery.NacosDiscoveryClientConfiguration

@Configuration(proxyBeanMethods = false)
@ConditionalOnDiscoveryEnabled
@ConditionalOnBlockingDiscoveryEnabled
@ConditionalOnNacosDiscoveryEnabled
@AutoConfigureBefore({ SimpleDiscoveryClientAutoConfiguration.class,
        CommonsClientAutoConfiguration.class })
@AutoConfigureAfter(NacosDiscoveryAutoConfiguration.class)
public class NacosDiscoveryClientConfiguration {

//注入nacos服务发现客户端
    @Bean
    public DiscoveryClient nacosDiscoveryClient(
            NacosServiceDiscovery nacosServiceDiscovery) {
        return new NacosDiscoveryClient(nacosServiceDiscovery);
    }

    //输入nacoswatch，该类在ApplicationContext启动后扫描到lifeCycle的实现类并调用start，订阅EventListener，如果是NamingEvent，则在需要的情况下重置元数据，另外，此类还会发布一次心跳HeartbeatEvent
    @Bean
    @ConditionalOnMissingBean
    @ConditionalOnProperty(value = "spring.cloud.nacos.discovery.watch.enabled",
            matchIfMissing = true)
    public NacosWatch nacosWatch(NacosServiceManager nacosServiceManager,
            NacosDiscoveryProperties nacosDiscoveryProperties,
            ObjectProvider<TaskScheduler> taskExecutorObjectProvider) {
        return new NacosWatch(nacosServiceManager, nacosDiscoveryProperties,
                taskExecutorObjectProvider);
    }

}

com.alibaba.cloud.nacos.discovery.configclient.NacosConfigServerAutoConfiguration

/**
 * Extra configuration for config server if it happens to be registered with Nacos.
 * 如果配置服务器恰巧已在Nacos中注册，则需要对配置服务器进行额外的配置
 *
 * @author JevonYang
 */
@Configuration(proxyBeanMethods = false)
@EnableConfigurationProperties
@ConditionalOnClass({NacosDiscoveryProperties.class, ConfigServerProperties.class})
public class NacosConfigServerAutoConfiguration {

    @Autowired(required = false)
    private NacosDiscoveryProperties properties;

    @Autowired(required = false)
    private ConfigServerProperties server;

    @PostConstruct
    public void init() {
        if (this.properties == null || this.server == null) {
            return;
        }
        String prefix = this.server.getPrefix();
        if (StringUtils.hasText(prefix) && !StringUtils
                .hasText(this.properties.getMetadata().get("configPath"))) {
            this.properties.getMetadata().put("configPath", prefix);
        }
    }

}

com.alibaba.cloud.nacos.discovery.configclient.NacosDiscoveryClientConfigServiceBootstrapConfiguration

@ConditionalOnClass(ConfigServicePropertySourceLocator.class)
@ConditionalOnProperty(value = "spring.cloud.config.discovery.enabled",
        matchIfMissing = false)
@Configuration(proxyBeanMethods = false)
@ImportAutoConfiguration({ NacosDiscoveryAutoConfiguration.class,
        NacosDiscoveryClientConfiguration.class,
        NacosReactiveDiscoveryClientConfiguration.class })
public class NacosDiscoveryClientConfigServiceBootstrapConfiguration {

}

将NacosDiscoveryAutoConfiguration.class,NacosDiscoveryClientConfiguration.class,NacosReactiveDiscoveryClientConfiguration.class注入到Bootstrap容器中