9.SpringBoot学习(九)——Spring Boot Admin使用
1.简介
1.1 概述
Spring Boot Admin is a community project to manage and monitor your Spring Boot ® applications. The applications register with our Spring Boot Admin Client (via HTTP) or are discovered using Spring Cloud ® (e.g. Eureka, Consul). The UI is just a Vue.js application on top of the Spring Boot Actuator endpoints.
Spring Boot Admin是一个社区项目，用于管理和监视Spring Boot® 应用程序。这些应用程序在我们的Spring Boot Admin Client中注册（通过HTTP），或者使用Spring Cloud®（例如，Eureka，Consul）发现。 UI只是Spring Boot Actuator端点之上的 Vue.js 应用程序。
1.2 特点
- Show health status：显示健康状况
- Show details, like：显示详细信息，例如
- JVM & memory metrics：JVM 和 内存指标
- micrometer.io metrics：micrometer io指标
- Datasource metrics：数据源指标
- Cache metrics：缓存指标
- Show build-info number：显示构建信息编号
- Follow and download logfile：追踪并下载日志文件
- View jvm system- & environment-properties：查看 jvm 系统属性和环境属性
- View Spring Boot Configuration Properties：查看 Spring Boot 配置属性
- Support for Spring Cloud’s postable /env- &/refresh-endpoint：支持Spring Cloud的可发布/ env-和// refresh-endpoint
- Easy loglevel management：轻松的日志级别管理
- Interact with JMX-beans：与JMX-beans交互
- View thread dump：查看线程转储
- View http-traces：查看http跟踪
- View auditevents：查看审计事件
- View http-endpoints：查看http端点
- View scheduled tasks：查看定时任务
- View and delete active sessions (using spring-session)：查看和删除活动会话（使用spring-session）
- View Flyway / Liquibase database migrations：查看Flyway / Liquibase数据库迁移
- Download heapdump：下载 heapdump
- Notification on status change (via e-mail, Slack, Hipchat, …)：状态更改通知（通过电子邮件，Slack，Hipchat等）
- Event journal of status changes (non persistent)：状态更改的事件日志（非持久性）
2.演示环境
- JDK 1.8.0_201
- Spring Boot 2.2.0.RELEASE
- 构建工具（apache maven 3.6.3）
- 开发工具（IntelliJ IDEA ）
3.演示代码
3.1 代码说明
使用 spring boot admin 需要两个项目：一个是 admin 项目，一个是 client 项目。admin 项目开启 SpringBoot Admin 功能，client 项目注册到 admin 项目上。
3.2 代码结构
3.3 maven 依赖
spring-boot-admin --> pom.xml
<modules>
<module>spring-boot-admin-servermodule>
<module>spring-boot-admin-clientmodule>
modules>
spring-boot-admin-server --> pom.xml
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>de.codecentricgroupId>
<artifactId>spring-boot-admin-starter-serverartifactId>
dependency>
dependencies>
spring-boot-admin-client --> pom.xml
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>de.codecentricgroupId>
<artifactId>spring-boot-admin-starter-clientartifactId>
dependency>
dependencies>
3.4 配置文件
spring-boot-admin-server --> application.properties
spring.application.name=spring-boot-admin-server
server.port=8080
spring-boot-admin-client --> application.properties
spring.application.name=spring-boot-admin-client
server.port=9090
# 指定admin-server地址
spring.boot.admin.client.url=http://localhost:8080
# 监控所有的endpoint
management.endpoints.web.exposure.include=*
3.5 java代码
SpringBootAdminServerApplication.java
@EnableAdminServer
@SpringBootApplication
public class SpringBootAdminServerApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootAdminServerApplication.class, args);
}
}
SpringBootAdminClientApplication.java
@SpringBootApplication
public class SpringBootAdminClientApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootAdminClientApplication.class, args);
}
}
3.6 git 地址
spring-boot/spring-boot-05-basis/spring-boot-admin
4.效果展示
先启动 SpringBootAdminServerApplication.main 方法，再启动 SpringBootAdminClientApplication.main 方法。
访问 http://localhost:8080/，会自动跳转到 Spring Boot Admin 界面，可以看到 spring-boot-admin-client 已经注册上来了
点击 spring-boot-admin-client，可以查看各项监控指标
5.源码分析
5.1 admin server 的请求原理
Spring Boot Admin 组件中，通过 @EnableAdminServer 标识一个 admin server 组件，并启动。EnableAdminServer 的内容如下.
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(AdminServerMarkerConfiguration.class)
public @interface EnableAdminServer {
}
EnableAdminServer 通过 @Import 导入一个 AdminServerMarkerConfiguration 配置类。
@Configuration(proxyBeanMethods = false)
public class AdminServerMarkerConfiguration {
@Bean
public Marker adminServerMarker() {
return new Marker();
}
public static class Marker {
}
}
AdminServerMarkerConfiguration 中定义了一个静态内部类 Marker，并将它声明为 Bean。那么这个 admin server 又是如何生效的呢？实际上，admin server 有一个自动装配类 AdminServerAutoConfiguration，这个类的内容如下。
@Configuration(proxyBeanMethods = false)
@ConditionalOnBean(AdminServerMarkerConfiguration.Marker.class)
@EnableConfigurationProperties(AdminServerProperties.class)
@ImportAutoConfiguration({ AdminServerInstanceWebClientConfiguration.class, AdminServerWebConfiguration.class })
@AutoConfigureAfter({ WebClientAutoConfiguration.class })
public class AdminServerAutoConfiguration {
private final AdminServerProperties adminServerProperties;
public AdminServerAutoConfiguration(AdminServerProperties adminServerProperties) {
this.adminServerProperties = adminServerProperties;
}
@Bean
@ConditionalOnMissingBean
public InstanceRegistry instanceRegistry(InstanceRepository instanceRepository,
InstanceIdGenerator instanceIdGenerator) {
return new InstanceRegistry(instanceRepository, instanceIdGenerator);
}
@Bean
@ConditionalOnMissingBean
public ApplicationRegistry applicationRegistry(InstanceRegistry instanceRegistry,
InstanceEventPublisher instanceEventPublisher) {
return new ApplicationRegistry(instanceRegistry, instanceEventPublisher);
}
@Bean
@ConditionalOnMissingBean
public InstanceIdGenerator instanceIdGenerator() {
return new HashingInstanceUrlIdGenerator();
}
@Bean
@ConditionalOnMissingBean
public StatusUpdater statusUpdater(InstanceRepository instanceRepository,
InstanceWebClient.Builder instanceWebClientBulder) {
return new StatusUpdater(instanceRepository, instanceWebClientBulder.build());
}
@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;
}
@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);
}
@Bean(initMethod = "start", destroyMethod = "stop")
@ConditionalOnMissingBean
public EndpointDetectionTrigger endpointDetectionTrigger(EndpointDetector endpointDetector,
Publisher<InstanceEvent> events) {
return new EndpointDetectionTrigger(endpointDetector, events);
}
@Bean
@ConditionalOnMissingBean
public InfoUpdater infoUpdater(InstanceRepository instanceRepository,
InstanceWebClient.Builder instanceWebClientBuilder) {
return new InfoUpdater(instanceRepository, instanceWebClientBuilder.build());
}
@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;
}
@Bean
@ConditionalOnMissingBean(InstanceEventStore.class)
public InMemoryEventStore eventStore() {
return new InMemoryEventStore();
}
@Bean(initMethod = "start", destroyMethod = "stop")
@ConditionalOnMissingBean(InstanceRepository.class)
public SnapshottingInstanceRepository instanceRepository(InstanceEventStore eventStore) {
return new SnapshottingInstanceRepository(eventStore);
}
}
AdminServerAutoConfiguration 通过 @ImportAutoConfiguration 导入了 AdminServerWebConfiguration 和
AdminServerInstanceWebClientConfiguration。查看 AdminServerWebConfiguration 内容
@Configuration(proxyBeanMethods = false)
public class AdminServerWebConfiguration {
private final AdminServerProperties adminServerProperties;
public AdminServerWebConfiguration(AdminServerProperties adminServerProperties) {
this.adminServerProperties = adminServerProperties;
}
@Bean
public SimpleModule adminJacksonModule() {
SimpleModule module = new SimpleModule();
module.addDeserializer(Registration.class, new RegistrationDeserializer());
module.setSerializerModifier(new RegistrationBeanSerializerModifier(
new SanitizingMapSerializer(this.adminServerProperties.getMetadataKeysToSanitize())));
return module;
}
@Bean
@ConditionalOnMissingBean
public InstancesController instancesController(InstanceRegistry instanceRegistry, InstanceEventStore eventStore) {
return new InstancesController(instanceRegistry, eventStore);
}
@Bean
@ConditionalOnMissingBean
public ApplicationsController applicationsController(ApplicationRegistry applicationRegistry) {
return new ApplicationsController(applicationRegistry);
}
// reactive web configuration ...
@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET)
@AutoConfigureAfter(WebMvcAutoConfiguration.class)
public static class ServletRestApiConfirguation {
private final AdminServerProperties adminServerProperties;
public ServletRestApiConfirguation(AdminServerProperties adminServerProperties) {
this.adminServerProperties = adminServerProperties;
}
@Bean
@ConditionalOnMissingBean
public de.codecentric.boot.admin.server.web.servlet.InstancesProxyController instancesProxyController(
InstanceRegistry instanceRegistry, InstanceWebClient.Builder instanceWebClientBuilder) {
return new de.codecentric.boot.admin.server.web.servlet.InstancesProxyController(
this.adminServerProperties.getContextPath(),
this.adminServerProperties.getInstanceProxy().getIgnoredHeaders(), instanceRegistry,
instanceWebClientBuilder.build());
}
@Bean
public org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping adminHandlerMapping(
ContentNegotiationManager contentNegotiationManager) {
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping mapping = new de.codecentric.boot.admin.server.web.servlet.AdminControllerHandlerMapping(
this.adminServerProperties.getContextPath());
mapping.setOrder(0);
mapping.setContentNegotiationManager(contentNegotiationManager);
return mapping;
}
}
}
默认 servlet 情况下，会使用 ServletRestApiConfirguation 配置，生成 web mvc 的服务。在 ServletRestApiConfirguation 声明了 AdminControllerHandlerMapping 的 RequestMappingHandlerMapping 实例对象。
这个 AdminControllerHandlerMapping 用来处理被 @AdminController 修饰的类
@Override
protected boolean isHandler(Class<?> beanType) {
return AnnotatedElementUtils.hasAnnotation(beanType, AdminController.class);
}
spring-boot-admin-server.jar 中提供了一些被 @AdminController 修饰的类，比如：ApplicationsController、NotificationFilterController、InstancesController、InstancesProxyController 等。ApplicationsController 内容如下。
@AdminController
@ResponseBody
public class ApplicationsController {
private static final Logger log = LoggerFactory.getLogger(ApplicationsController.class);
private static final ServerSentEvent<?> PING = ServerSentEvent.builder().comment("ping").build();
private static final Flux<ServerSentEvent<?>> PING_FLUX = Flux.interval(Duration.ZERO, Duration.ofSeconds(10L))
.map((tick) -> PING);
private final ApplicationRegistry registry;
public ApplicationsController(ApplicationRegistry registry) {
this.registry = registry;
}
@GetMapping(path = "/applications", produces = MediaType.APPLICATION_JSON_VALUE)
public Flux<Application> applications() {
return registry.getApplications();
}
@GetMapping(path = "/applications/{name}", produces = MediaType.APPLICATION_JSON_VALUE)
public Mono<ResponseEntity<Application>> application(@PathVariable("name") String name) {
return registry.getApplication(name).map(ResponseEntity::ok).defaultIfEmpty(ResponseEntity.notFound().build());
}
@GetMapping(path = "/applications", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
public Flux<ServerSentEvent<Application>> applicationsStream() {
return registry.getApplicationStream().map((application) -> ServerSentEvent.builder(application).build())
.mergeWith(ping());
}
@DeleteMapping(path = "/applications/{name}")
public Mono<ResponseEntity<Void>> unregister(@PathVariable("name") String name) {
log.debug("Unregister application with name '{}'", name);
return registry.deregister(name).collectList().map((deregistered) -> !deregistered.isEmpty()
? ResponseEntity.noContent().build() : ResponseEntity.notFound().build());
}
@SuppressWarnings("unchecked")
private static <T> Flux<ServerSentEvent<T>> ping() {
return (Flux<ServerSentEvent<T>>) (Flux) PING_FLUX;
}
}
其中 applications() 方法刚好处理 http://localhost:8080/ 跳转后的 http://localhost:8080/applications 请求。
5.2 server 和 client 之间通信
在 spring-boot-admin-server 中有自动装配类 AdminServerAutoConfiguration，相应地，在 spring-boot-admin-client 也有一个自动装配类。它是 SpringBootAdminClientAutoConfiguration。
这个 SpringBootAdminClientAutoConfiguration 声明了如下主要类型
@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication
@Conditional(SpringBootAdminClientEnabledCondition.class)
@AutoConfigureAfter({ WebEndpointAutoConfiguration.class, RestTemplateAutoConfiguration.class, WebClientAutoConfiguration.class })
@EnableConfigurationProperties({ ClientProperties.class, InstanceProperties.class, ServerProperties.class, ManagementServerProperties.class })
public class SpringBootAdminClientAutoConfiguration {
@Bean
@ConditionalOnMissingBean
public ApplicationRegistrator registrator(RegistrationClient registrationClient, ClientProperties client, ApplicationFactory applicationFactory) {
return new ApplicationRegistrator(applicationFactory, registrationClient, client.getAdminUrl(), client.isRegisterOnce());
}
@Bean
@ConditionalOnMissingBean
public RegistrationApplicationListener registrationListener(ClientProperties client,
ApplicationRegistrator registrator, Environment environment) {
RegistrationApplicationListener listener = new RegistrationApplicationListener(registrator);
listener.setAutoRegister(client.isAutoRegistration());
listener.setAutoDeregister(client.isAutoDeregistration(environment));
listener.setRegisterPeriod(client.getPeriod());
return listener;
}
@Bean
@ConditionalOnMissingBean
public StartupDateMetadataContributor startupDateMetadataContributor() {
return new StartupDateMetadataContributor();
}
@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication(type = Type.SERVLET)
@AutoConfigureAfter(DispatcherServletAutoConfiguration.class)
public static class ServletConfiguration {
@Bean
@ConditionalOnMissingBean
public ApplicationFactory applicationFactory(InstanceProperties instance, ManagementServerProperties management, ServerProperties server, ServletContext servletContext, PathMappedEndpoints pathMappedEndpoints, WebEndpointProperties webEndpoint, ObjectProvider<List<MetadataContributor>> metadataContributors, DispatcherServletPath dispatcherServletPath) {
return new ServletApplicationFactory(instance, management, server, servletContext, pathMappedEndpoints, webEndpoint, new CompositeMetadataContributor(
metadataContributors.getIfAvailable(Collections::emptyList)), dispatcherServletPath);
}
}
@Configuration(proxyBeanMethods = false)
@ConditionalOnBean(RestTemplateBuilder.class)
public static class BlockingRegistrationClientConfig {
@Bean
@ConditionalOnMissingBean
public BlockingRegistrationClient registrationClient(ClientProperties client) {
RestTemplateBuilder builder = new RestTemplateBuilder().setConnectTimeout(client.getConnectTimeout())
.setReadTimeout(client.getReadTimeout());
if (client.getUsername() != null && client.getPassword() != null) {
builder = builder.basicAuthentication(client.getUsername(), client.getPassword());
}
return new BlockingRegistrationClient(builder.build());
}
}
// ...
}
ApplicationRegistrator 用来注册到 admin-server，其中定义了 register 和 deregister 方法
/**
* Registers the client application at spring-boot-admin-server
*/
public class ApplicationRegistrator {
private static final Logger LOGGER = LoggerFactory.getLogger(ApplicationRegistrator.class);
private final ConcurrentHashMap<String, LongAdder> attempts = new ConcurrentHashMap<>();
private final AtomicReference<String> registeredId = new AtomicReference<>();
private final ApplicationFactory applicationFactory;
private final String[] adminUrls;
private final boolean registerOnce;
private final RegistrationClient registrationClient;
public ApplicationRegistrator(ApplicationFactory applicationFactory, RegistrationClient registrationClient,
String[] adminUrls, boolean registerOnce) {
this.applicationFactory = applicationFactory;
this.adminUrls = adminUrls;
this.registerOnce = registerOnce;
this.registrationClient = registrationClient;
}
/**
* Registers the client application at spring-boot-admin-server.
* @return true if successful registration on at least one admin server
*/
public boolean register() {
Application application = this.applicationFactory.createApplication();
boolean isRegistrationSuccessful = false;
for (String adminUrl : this.adminUrls) {
LongAdder attempt = this.attempts.computeIfAbsent(adminUrl, (k) -> new LongAdder());
boolean successful = register(application, adminUrl, attempt.intValue() == 0);
if (!successful) {
attempt.increment();
}
else {
attempt.reset();
isRegistrationSuccessful = true;
if (this.registerOnce) {
break;
}
}
}
return isRegistrationSuccessful;
}
protected boolean register(Application application, String adminUrl, boolean firstAttempt) {
try {
String id = this.registrationClient.register(adminUrl, application);
if (this.registeredId.compareAndSet(null, id)) {
LOGGER.info("Application registered itself as {}", id);
}
else {
LOGGER.debug("Application refreshed itself as {}", id);
}
return true;
}
catch (Exception ex) {
if (firstAttempt) {
LOGGER.warn(
"Failed to register application as {} at spring-boot-admin ({}): {}. Further attempts are logged on DEBUG level",
application, this.adminUrls, ex.getMessage());
}
else {
LOGGER.debug("Failed to register application as {} at spring-boot-admin ({}): {}", application,
this.adminUrls, ex.getMessage());
}
return false;
}
}
public void deregister() {
String id = this.registeredId.get();
if (id == null) {
return;
}
for (String adminUrl : this.adminUrls) {
try {
this.registrationClient.deregister(adminUrl, id);
this.registeredId.compareAndSet(id, null);
if (this.registerOnce) {
break;
}
}
catch (Exception ex) {
LOGGER.warn("Failed to deregister application (id={}) at spring-boot-admin ({}): {}", id, adminUrl,
ex.getMessage());
}
}
}
/**
* @return the id of this client as given by the admin server. Returns null if the
* client has not registered against the admin server yet.
*/
public String getRegisteredId() {
return this.registeredId.get();
}
}
RegistrationApplicationListener 则是用来触发开始注册和停止注册任务，它实现了 InitializingBean 和 DisposableBean 接口，分别定定义了初始化完成后和销毁前的处理方式。
private final ThreadPoolTaskScheduler taskScheduler;
public RegistrationApplicationListener(ApplicationRegistrator registrator) {
this(registrator, registrationTaskScheduler());
}
// 声明线程池
private static ThreadPoolTaskScheduler registrationTaskScheduler() {
ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
taskScheduler.setPoolSize(1);
taskScheduler.setRemoveOnCancelPolicy(true);
taskScheduler.setThreadNamePrefix("registrationTask");
return taskScheduler;
}
RegistrationApplicationListener(ApplicationRegistrator registrator, ThreadPoolTaskScheduler taskScheduler) {
this.registrator = registrator;
this.taskScheduler = taskScheduler;
}
// 实现 InitializingBean 中 afterPropertiesSet 方法
@Override
public void afterPropertiesSet() {
taskScheduler.afterPropertiesSet();
}
// 实现 DisposableBean 中 destroy 方法
@Override
public void destroy() {
taskScheduler.destroy();
}
同时，它还接收 ApplicationReadyEvent 事件和 ContextClosedEvent 事件
// 接收 ApplicationReadyEvent 事件
@EventListener
@Order(Ordered.LOWEST_PRECEDENCE)
public void onApplicationReady(ApplicationReadyEvent event) {
if (autoRegister) {
// 启动开始注册任务
startRegisterTask();
}
}
// 接收 ContextClosedEvent 事件
@EventListener
@Order(Ordered.LOWEST_PRECEDENCE)
public void onClosedContext(ContextClosedEvent event) {
if (event.getApplicationContext().getParent() == null
|| "bootstrap".equals(event.getApplicationContext().getParent().getId())) {
// 停止注册任务
stopRegisterTask();
if (autoDeregister) {
// 删除注册内容
registrator.deregister();
}
}
}
// 启动注册任务
public void startRegisterTask() {
if (scheduledTask != null && !scheduledTask.isDone()) {
return;
}
// 开启定时任务，默认执行周期 10s，定时任务调用 registrator::register 方法
scheduledTask = taskScheduler.scheduleAtFixedRate(registrator::register, registerPeriod);
LOGGER.debug("Scheduled registration task for every {}ms", registerPeriod);
}
// 停止注册任务
public void stopRegisterTask() {
if (scheduledTask != null && !scheduledTask.isDone()) {
// 取消任务
scheduledTask.cancel(true);
LOGGER.debug("Canceled registration task");
}
}
其中 registrator.register 实现如下
public boolean register() {
Application application = this.applicationFactory.createApplication();
boolean isRegistrationSuccessful = false;
for (String adminUrl : this.adminUrls) {
LongAdder attempt = this.attempts.computeIfAbsent(adminUrl, (k) -> new LongAdder());
// 注册
boolean successful = register(application, adminUrl, attempt.intValue() == 0);
if (!successful) {
attempt.increment();
}
else {
attempt.reset();
isRegistrationSuccessful = true;
if (this.registerOnce) {
break;
}
}
}
return isRegistrationSuccessful;
}
protected boolean register(Application application, String adminUrl, boolean firstAttempt) {
try {
// 调用 registrationClient 的 register 方法
String id = this.registrationClient.register(adminUrl, application);
if (this.registeredId.compareAndSet(null, id)) {
LOGGER.info("Application registered itself as {}", id);
}
else {
LOGGER.debug("Application refreshed itself as {}", id);
}
return true;
}
catch (Exception ex) {
if (firstAttempt) {
LOGGER.warn(
"Failed to register application as {} at spring-boot-admin ({}): {}. Further attempts are logged on DEBUG level",
application, this.adminUrls, ex.getMessage());
}
else {
LOGGER.debug("Failed to register application as {} at spring-boot-admin ({}): {}", application,
this.adminUrls, ex.getMessage());
}
return false;
}
}
最终调用 registrationClient.register 方法，它的实现如下
public class BlockingRegistrationClient implements RegistrationClient {
private static final ParameterizedTypeReference<Map<String, Object>> RESPONSE_TYPE = new ParameterizedTypeReference<Map<String, Object>>() {
};
private final RestTemplate restTemplate;
public BlockingRegistrationClient(RestTemplate restTemplate) {
this.restTemplate = restTemplate;
}
// 向指定的 adminUrl 方式 Post 请求
@Override
public String register(String adminUrl, Application application) {
ResponseEntity<Map<String, Object>> response = this.restTemplate.exchange(adminUrl, HttpMethod.POST, new HttpEntity<>(application, this.createRequestHeaders()), RESPONSE_TYPE);
return response.getBody().get("id").toString();
}
protected HttpHeaders createRequestHeaders() {
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));
return HttpHeaders.readOnlyHttpHeaders(headers);
}
}
registrator.deregister
public void deregister() {
String id = this.registeredId.get();
if (id == null) {
return;
}
for (String adminUrl : this.adminUrls) {
try {
// 调用 registrationClient 的 deregister 方法
this.registrationClient.deregister(adminUrl, id);
this.registeredId.compareAndSet(id, null);
if (this.registerOnce) {
break;
}
}
catch (Exception ex) {
LOGGER.warn("Failed to deregister application (id={}) at spring-boot-admin ({}): {}", id, adminUrl, ex.getMessage());
}
}
}
最终调用 registrationClient.deregister 方法，它的实现如下
@Override
public void deregister(String adminUrl, String id) {
// 调用 Delete 方法
this.restTemplate.delete(adminUrl + '/' + id);
}
6.参考
- Spring Boot Admin