Spring Boot Admin2 AdminServerAutoConfiguration详解

àì夳堔傛蜴生んèń 2024-03-31 10:17 49阅读 0赞

> 其他相关文章：
> 
> 1.  [Spring Boot Admin 参考指南][Spring Boot Admin]
> 2.  [SpringBoot Admin服务离线、不显示健康信息的问题][SpringBoot Admin]
> 3.  [Spring Boot Admin2 @EnableAdminServer的加载][Spring Boot Admin2 _EnableAdminServer]

前面已经分析了@EnableAdminServer的作用，唯一的功能是将`AdminServerMarkerConfiguration.Marker`类加载到Spring中，并且知道了`AdminServerAutoConfiguration`类的加载依赖于`AdminServerMarkerConfiguration.Marker`类。  
这篇文章主要来分析AdminServerAutoConfiguration的作用，加载了哪些东西。

首先AdminServerAutoConfiguration类头部有如下几个注解：

@Configuration(proxyBeanMethods = false)
    @Conditional(SpringBootAdminServerEnabledCondition.class)
    @ConditionalOnBean(AdminServerMarkerConfiguration.Marker.class)
    @EnableConfigurationProperties(AdminServerProperties.class)
    @ImportAutoConfiguration({
         AdminServerInstanceWebClientConfiguration.class, AdminServerWebConfiguration.class })
    @AutoConfigureAfter({
         WebClientAutoConfiguration.class })
    @Lazy(false)

*  @Configuration(proxyBeanMethods = false)  
    表示是一个配置类，并且不被Spring 代理，如同普通类一样
 *  @Conditional(SpringBootAdminServerEnabledCondition.class)  
    根据SpringBootAdminServerEnabledCondition做为条件判断是否加载该类，SpringBootAdminServerEnabledCondition中根据`spring.boot.admin.server.enabled`是否为true来处理，优先级最高
 *  @ConditionalOnBean(AdminServerMarkerConfiguration.Marker.class)  
    判断Spring容器中是否存在AdminServerMarkerConfiguration.Marker 的Bean
 *  @EnableConfigurationProperties(AdminServerProperties.class)  
    启用AdminServerProperties配置文件，AdminServerProperties能够做为Bean 注入该类，其是我们常用的`spring.boot.admin` 相关配置
 *  @ImportAutoConfiguration(\{ AdminServerInstanceWebClientConfiguration.class, AdminServerWebConfiguration.class \})  
    加载AdminServerInstanceWebClientConfiguration、AdminServerWebConfiguration配置类。AdminServerInstanceWebClientConfiguration 包括了一系列服务实例Http调用相关的Bean配置。AdminServerWebConfiguration定义了SBA2监控相关的接口Controller，以及ReactiveRestApiConfiguration和ServletRestApiConfirguation相关的配置
 *  @AutoConfigureAfter(\{ WebClientAutoConfiguration.class \})  
    顾名思义，表示该类将在WebClientAutoConfiguration载入后，再加载
 *  @Lazy(false)  
    表示不延迟加载，覆盖默认配置

再往下看，是构造器部分

private final AdminServerProperties adminServerProperties;
    
    	public AdminServerAutoConfiguration(AdminServerProperties adminServerProperties) {
        
    		this.adminServerProperties = adminServerProperties;
    	}

这里将AdminServerProperties配置以构造器的方式注入该类

继续看其他加载的配置

@Bean
    	@ConditionalOnMissingBean
    	public InstanceRegistry instanceRegistry(InstanceRepository instanceRepository,
    			InstanceIdGenerator instanceIdGenerator) {
        
    		return new InstanceRegistry(instanceRepository, instanceIdGenerator);
    	}

该部分创建了一个用于管理实例注册的Bean，InstanceRepository 用于提供实例的持久化，InstanceIdGenerator 用于生成实例id

@Bean
    	@ConditionalOnMissingBean
    	public ApplicationRegistry applicationRegistry(InstanceRegistry instanceRegistry,
    			InstanceEventPublisher instanceEventPublisher) {
        
    		return new ApplicationRegistry(instanceRegistry, instanceEventPublisher);
    	}

该部分创建一个用于管理所有已注册的应用

@Bean
    	@ConditionalOnMissingBean
    	public InstanceIdGenerator instanceIdGenerator() {
        
    		return new HashingInstanceUrlIdGenerator();
    	}

该部分创建了一个根据实例健康URL地址来生成实例ID的Bean

@Bean
    	@ConditionalOnMissingBean
    	public StatusUpdater statusUpdater(InstanceRepository instanceRepository,
    			InstanceWebClient.Builder instanceWebClientBulder) {
        
    		return new StatusUpdater(instanceRepository, instanceWebClientBulder.build());
    	}

该部分创建了一个用于查询更新实例状态的Bean

@Bean(initMethod = "start", destroyMethod = "stop")
    	@ConditionalOnMissingBean
    	public StatusUpdateTrigger statusUpdateTrigger(StatusUpdater statusUpdater, Publisher<InstanceEvent> events) {
        
    		StatusUpdateTrigger trigger = new StatusUpdateTrigger(statusUpdater, events);
    		trigger.setInterval(this.adminServerProperties.getMonitor().getStatusInterval());
    		trigger.setLifetime(this.adminServerProperties.getMonitor().getStatusLifetime());
    		return trigger;
    	}

StatusUpdateTrigger 会在加载的时候开启一个定时任务，用来检查所有实例的状态，检测周期和状态生存时间可以通过`spring.boot.admin.monitor.status-interval`和`spring.boot.admin.monitor.status-lifetime`配置。除此之外，其监听了实例变更事件，会在实例注册和实例更新的时候，触发去更新实例状态。

@Bean
    	@ConditionalOnMissingBean
    	public EndpointDetector endpointDetector(InstanceRepository instanceRepository,
    			InstanceWebClient.Builder instanceWebClientBuilder) {
        
    		InstanceWebClient instanceWebClient = instanceWebClientBuilder.build();
    		ChainingStrategy strategy = new ChainingStrategy(new QueryIndexEndpointStrategy(instanceWebClient),
    				new ProbeEndpointsStrategy(instanceWebClient, this.adminServerProperties.getProbedEndpoints()));
    		return new EndpointDetector(instanceRepository, strategy);
    	}

EndpointDetector 用于检测实例暴露的端点

@Bean(initMethod = "start", destroyMethod = "stop")
    	@ConditionalOnMissingBean
    	public EndpointDetectionTrigger endpointDetectionTrigger(EndpointDetector endpointDetector,
    			Publisher<InstanceEvent> events) {
        
    		return new EndpointDetectionTrigger(endpointDetector, events);
    	}

EndpointDetectionTrigger 实例端点检测触发器，在实例状态变更和实例注册更新的时候，触发检测

@Bean
    	@ConditionalOnMissingBean
    	public InfoUpdater infoUpdater(InstanceRepository instanceRepository,
    			InstanceWebClient.Builder instanceWebClientBuilder) {
        
    		return new InfoUpdater(instanceRepository, instanceWebClientBuilder.build());
    	}

InfoUpdater 调用`info`接口，更新实例信息

@Bean(initMethod = "start", destroyMethod = "stop")
    	@ConditionalOnMissingBean
    	public InfoUpdateTrigger infoUpdateTrigger(InfoUpdater infoUpdater, Publisher<InstanceEvent> events) {
        
    		InfoUpdateTrigger trigger = new InfoUpdateTrigger(infoUpdater, events);
    		trigger.setInterval(this.adminServerProperties.getMonitor().getInfoInterval());
    		trigger.setLifetime(this.adminServerProperties.getMonitor().getInfoLifetime());
    		return trigger;
    	}

InfoUpdateTrigger 实例信息检查触发器，道理同`StatusUpdateTrigger`

@Bean
    	@ConditionalOnMissingBean(InstanceEventStore.class)
    	public InMemoryEventStore eventStore() {
        
    		return new InMemoryEventStore();
    	}

InMemoryEventStore 实例存储类，基于ConcurrentMap

@Bean(initMethod = "start", destroyMethod = "stop")
    	@ConditionalOnMissingBean(InstanceRepository.class)
    	public SnapshottingInstanceRepository instanceRepository(InstanceEventStore eventStore) {
        
    		return new SnapshottingInstanceRepository(eventStore);
    	}

SnapshottingInstanceRepository 实例持久化类，用于操作InstanceEventStore

到此AdminServerAutoConfiguration自动配置类结束

[Spring Boot Admin]: https://itsaysay.blog.csdn.net/article/details/125567451
[SpringBoot Admin]: https://itsaysay.blog.csdn.net/article/details/125302909
[Spring Boot Admin2 _EnableAdminServer]: https://itsaysay.blog.csdn.net/article/details/127986764