EurekaServerAutoConfiguration 思维导图模板_ProcessOn思维导图、流程图

源码

@Configuration 首先当前类是一个配置类

@Import(EurekaServerInitializerConfiguration.class)

源码

核心方法： start()

eurekaServerBootstrap.contextInitialized(EurekaServerInitializerConfiguration.this.servletContext);

@Autowired private EurekaServerBootstrap eurekaServerBootstrap;

源码

核心方法：public void contextInitialized(ServletContext context)

initEurekaEnvironment();

判断dataCenter 是否是null 如果是null 则给ARCHAIUS_DEPLOYMENT_DATACENTER设置为DEFAULT,否则设置为dataCenter

判断environment 是否是null,如果是null 则给ARCHAIUS_DEPLOYMENT_ENVIRONMENT 设置为DEFAULT否则设置为 TEST

initEurekaServerContext();

先认识一下XStream 类

源码

官方源码解释说明

JsonXStream

JsonXStream extends XStream

官方源码解释说明

XmlXStream

XmlXStream extends XStream

官方源码解释说明

this.applicationInfoManager.getInfo()

ApplicationInfoManager

源码

我们可以用来干什么呢？

我们可以在EurekaServer 中 

pom 中添加web 的依赖

写一个Controller 方法

源码

我们可以看到我们可以通过它获取服务的配置对象，以及服务的详细信息对象，以及设置服务的状态，添加一个监听器等等

EurekaServerContextHolder.initialize(this.serverContext);

方法源码

源码注释说明

EurekaServerContextHolder.initialize(this.serverContext);

源码

// Copy registry from neighboring eureka node int registryCount = this.registry.syncUp();

说明： 从相邻的eureka节点复制注册表

从 syncUp() 方法的代码中可以知道是30s一次

方法代码

源码

源码注释

这个类就是EurekaServer的启动引导类

start() 方法中用到了 servletContext

这个值是在什么时候被设置进来的？

当项目启动，IOC 容器初始化的时候，会调用ServletContextAwareProcessor 类的：public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException 方法

@ConditionalOnBean(EurekaServerMarkerConfiguration.Marker.class)

根据源码注释可知，该注解的作用是往IOC 容器中创建一个Marker bean  用来标识  EurekaServerAutoConfiguration 配置是否已经被激活，也就是说如果IOC 容器中存在这个bean 那么该配置就已经被加载激活过，否则则没有。

@EnableConfigurationProperties({ EurekaDashboardProperties.class, InstanceRegistryProperties.class })

@PropertySource("classpath:/eureka/server.properties")

@Autowired private ApplicationInfoManager applicationInfoManager;

EurekaClientAutoConfiguration  配置类中实例化的

@Autowired private EurekaServerConfig eurekaServerConfig;

实例化方法

@Configuration protected static class EurekaServerConfigBeanConfiguration { @Bean @ConditionalOnMissingBean public EurekaServerConfig eurekaServerConfig(EurekaClientConfig clientConfig) { EurekaServerConfigBean server = new EurekaServerConfigBean(); if (clientConfig.shouldRegisterWithEureka()) { // Set a sensible default if we are supposed to replicate server.setRegistrySyncRetries(5); } return server; } }

@Autowired private EurekaClientConfig eurekaClientConfig;

EurekaClientAutoConfiguration 配置类中实例化的

@Autowired private EurekaClient eurekaClient;

EurekaClientAutoConfiguration 配置类中实例化的

@Autowired private InstanceRegistryProperties instanceRegistryProperties;

实例化

@EnableConfigurationProperties({ EurekaDashboardProperties.class, InstanceRegistryProperties.class })

InstanceRegistryProperties.class

源码

@ConfigurationProperties

源码

印象笔记：@ConfigurationProperties 注解使用姿势，这一篇就够了

@EnableConfigurationProperties

源码

@Import(EnableConfigurationPropertiesImportSelector.class)

源码

这个注解可以接收一个vale 数组并且把该数组的 class 注册进IOC 容器

那我们分析一下这个注解是怎么起作用的

首先是系统启动加载了：@EnableAutoConfiguration

源码

@EnableAutoConfiguration  @Import 了EnableAutoConfigurationImportSelector.class

EnableAutoConfigurationImportSelector 类的 selectImports 会获取到：ConfigurationPropertiesAutoConfiguration 这个类

源码

@Import(EnableConfigurationPropertiesImportSelector.class)

源码

核心

org.springframework.boot.context.properties.EnableConfigurationPropertiesImportSelector.ConfigurationPropertiesBeanRegistrar#registerBeanDefinitions

源码

把注解value  进行注入

@Bean public HasFeatures eurekaServerFeature()

核心代码

@Bean public HasFeatures eurekaServerFeature() { return HasFeatures.namedFeature("Eureka Server", EurekaServerAutoConfiguration.class); }

就是创建了一个名称和EurekaServerAutoConfiguration  key  value 对应关系的一个对象

我们可以自己添加映射关系

EurekaClientAutoConfiguration  配置类里面也有这么类型的一个对象

@Bean public HasFeatures eurekaFeature() { return HasFeatures.namedFeature("Eureka Client", EurekaClient.class); }

HasFeatures

源码

@Configuration protected static class EurekaServerConfigBeanConfiguration

核心代码

@Configuration protected static class EurekaServerConfigBeanConfiguration { @Bean @ConditionalOnMissingBean public EurekaServerConfig eurekaServerConfig(EurekaClientConfig clientConfig) { EurekaServerConfigBean server = new EurekaServerConfigBean(); if (clientConfig.shouldRegisterWithEureka()) { // Set a sensible default if we are supposed to replicate server.setRegistrySyncRetries(5); } return server; } }

就是创建了EurekaServerConfig  的实例对象

@Bean @ConditionalOnProperty(prefix = "eureka.dashboard", name = "enabled", matchIfMissing = true) public EurekaController eurekaController()

这个实际上就是Eureka 自带的一个Controller 类，对我提供暴露了一下接口

EurekaController

源码

@Bean public ServerCodecs serverCodecs()

创建了一个编码解码器

@Bean public PeerAwareInstanceRegistry peerAwareInstanceRegistry

初始化集群注册表

@Bean @ConditionalOnMissingBean public PeerEurekaNodes peerEurekaNodes(PeerAwareInstanceRegistry registry, ServerCodecs serverCodecs)

初始化集群节点集合

@Bean public EurekaServerContext eurekaServerContext(ServerCodecs serverCodecs, PeerAwareInstanceRegistry registry, PeerEurekaNodes peerEurekaNodes)

基于EurekaServer配置注册表集群节点集合以及服务初始化EurekaServer上下文

@Bean public EurekaServerBootstrap eurekaServerBootstrap(PeerAwareInstanceRegistry registry, EurekaServerContext serverContext)

核心方法

@Bean public EurekaServerBootstrap eurekaServerBootstrap(PeerAwareInstanceRegistry registry, EurekaServerContext serverContext) { return new EurekaServerBootstrap(this.applicationInfoManager, this.eurekaClientConfig, this.eurekaServerConfig, registry, serverContext); }

源码

这个是 EurekaServer 启动初始化的入口

流程

我们EurekaServerAutoConfiguration 配置类中的Bean 全部初始化之后

EurekaServerAutoConfiguration   的注解  @Import(EurekaServerInitializerConfiguration.class) 实现了SmartLifecycle    实现了这个接口的会在项目启动后，调用start() 方法

start() 方法中调用了eurekaServerBootstrap.contextInitialized(EurekaServerInitializerConfiguration.this.servletContext);

初始化EurekaServer

核心代码

public void contextInitialized(ServletContext context) { try { initEurekaEnvironment(); initEurekaServerContext(); context.setAttribute(EurekaServerContext.class.getName(), this.serverContext); } catch (Throwable e) { log.error("Cannot bootstrap eureka server :", e); throw new RuntimeException("Cannot bootstrap eureka server :", e); } }

initEurekaEnvironment();

initEurekaServerContext();

int registryCount = this.registry.syncUp();

从相邻的eureka节点复制注册表

源码

Applications apps = eurekaClient.getApplications();

this.registry.openForTraffic(this.applicationInfoManager, registryCount);

1. 修改eureka状态为up 2. 开启一个定时任务，清理60s没有续约实例

@Override public void openForTraffic(ApplicationInfoManager applicationInfoManager, int count) { // Renewals happen every 30 seconds and for a minute it should be a factor of 2. this.expectedNumberOfRenewsPerMin = count * 2; this.numberOfRenewsPerMinThreshold = (int) (this.expectedNumberOfRenewsPerMin * serverConfig.getRenewalPercentThreshold()); logger.info("Got " + count + " instances from neighboring DS node"); logger.info("Renew threshold is: " + numberOfRenewsPerMinThreshold); this.startupTime = System.currentTimeMillis(); if (count > 0) { this.peerInstancesTransferEmptyOnStartup = false; } DataCenterInfo.Name selfName = applicationInfoManager.getInfo().getDataCenterInfo().getName(); boolean isAws = Name.Amazon == selfName; if (isAws && serverConfig.shouldPrimeAwsReplicaConnections()) { logger.info("Priming AWS connections for all replicas.."); primeAwsReplicas(applicationInfoManager); } logger.info("Changing status to UP"); applicationInfoManager.setInstanceStatus(InstanceStatus.UP); super.postInit(); }

核心方法

primeAwsReplicas(applicationInfoManager);

super.postInit();

protected void postInit() { renewsLastMin.start(); if (evictionTaskRef.get() != null) { evictionTaskRef.get().cancel(); } evictionTaskRef.set(new EvictionTask()); evictionTimer.schedule(evictionTaskRef.get(), serverConfig.getEvictionIntervalTimerInMs(), serverConfig.getEvictionIntervalTimerInMs()); }

publish(new EurekaRegistryAvailableEvent(getEurekaServerConfig()))

发布注册中心启动事件

EurekaServerInitializerConfiguration.this.running = true

标记EurekaServer 处于运行中

publish(new EurekaServerStartedEvent(getEurekaServerConfig()));

注册中心服务启动事件

@Bean public FilterRegistrationBean jerseyFilterRegistration( javax.ws.rs.core.Application eurekaJerseyApp)

实现过滤器的一种方式

实现过滤器有两种方式

通过FilterRegistrationBean实例注册

通过@WebFilter注解生效

第一种相对于第二种的优点是，可以自己设置过滤器之间的优先级

@Bean public javax.ws.rs.core.Application jerseyApplication(Environment environment, ResourceLoader resourceLoader)

@Bean public FilterRegistrationBean traceFilterRegistration( @Qualifier("webRequestLoggingFilter") Filter filter)

EurekaClientAutoConfiguration 是 springboot 启动的时候 org.springframework.boot.autoconfigure.AutoConfigurationImportSelector#selectImports 方法加载的

源码

核心代码

configurations = sort(configurations, autoConfigurationMetadata);

排序之后我们发现是先加载 EurekaClientAutoConfiguration  然后再加载EurekaServerAutoConfiguration

EurekaServerAutoConfiguration 配置类的很多@Autowired 注入的对象都是在 EurekaClientAutoConfiguration 中实例化的

1

@Autowired private ApplicationInfoManager applicationInfoManager;

@Autowired private EurekaClient eurekaClient;

这两个是

2

@Autowired private EurekaClientConfig eurekaClientConfig;

@Bean @ConditionalOnMissingBean(value = EurekaClientConfig.class, search = SearchStrategy.CURRENT) public EurekaClientConfigBean eurekaClientConfigBean() { EurekaClientConfigBean client = new EurekaClientConfigBean(); if ("bootstrap".equals(this.env.getProperty("spring.config.name"))) { // We don't register during bootstrap by default, but there will be another // chance later. client.setRegisterWithEureka(false); } return client; }

EurekaClientConfigBean

我们可以通过打断点发现  这个return 的client  和EurekaServerAutoConfiguration 注入的对象是同一个