Java: Spring Boot Actuator源码分析

简述

Actuator相关代码在spring-boot-actuator-[version].jar下面.

1. DefaultListableBeanFactory.getBeanNamesForAnnotation() : 按照Annotation类名来获取Bean实例名;
2. EndpointDiscoverer.createEndpointBeans() : 按照获取到的Bean实例名创建EndpointBean
3. AbstractWebMvcEndpointHandlerMapping.initHandlerMethods() : 根据刚才查找到的enpoints列表进行注册.
4. AbstractWebMvcEndpointHandlerMapping:createRequestMappingInfo():创建url信息(类似于@RequestMapping)
5. OnEnabledEndpointCondition.getMatchOutcome() : 获取配置文件中management.endpoint.[id].enabled的值,[id]为变量值,类似management.endpoint.shutdown.enabled.

端点及处理方法在应用启动时初始化

注册端点处理方法处理流程是:

1. org.springframework.boot.actuate.endpoint.annotation.EndpointDiscoverer:getEndpoints()
2. org.springframework.boot.actuate.endpoint.annotation.EndpointDiscoverer:discoverEndpoints()
3. org.springframework.boot.actuate.endpoint.annotation.EndpointDiscoverer:convertToEndpoints(Collection endpointBeans)
4. org.springframework.boot.actuate.endpoint.annotation.EndpointDiscoverer:convertToEndpoint(EndpointBean endpointBean)
5. org.springframework.boot.actuate.endpoint.annotation.EndpointDiscoverer:addOperations(MultiValueMap indexed, EndpointId id,
   Object target, boolean replaceLast)
6. org.springframework.boot.actuate.endpoint.annotation.DiscoveredOperationsFactory:createOperations(EndpointId id, Object target)
7. 待续.

获取端点处理方法在:

org.springframework.core.MethodIntrospector:selectMethods();

在端点处理类（比如:org.springframework.boot.actuate.health.HealthEndpoint）的方法上添加@ReadOperation(GET)、@WriteOperation(POST)、@DeleteOperation(DELETE)可以暴露该方法到路由中,同时可以在方法参数上添加@Selector指定子端点(例如:org.springframework.boot.actuate.health.HealthEndpoint:healthForComponent(@Selector String component)方法)

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WebEndpointProperties: 获取配置文件中actuator服务的前缀.