Spring Boot Actuator-JMX Endpoints

朱雀 2022-12-28 11:19 132阅读 0赞

建议按顺序阅读，请戳《[初识篇][Link 1]》《[WEB Endpoints][]》

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JMX Endpoints，以JMX形式对外提供访问接口。（JMX（Java Management Extensions，即Java管理扩展）是一个为应用程序、设备、系统等[植入][Link 2]管理功能的框架。）

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# **█ 自动配置** #

META-INF/spring.factories：

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
    org.springframework.boot.actuate.autoconfigure.endpoint.EndpointAutoConfiguration,\
    org.springframework.boot.actuate.autoconfigure.endpoint.jmx.JmxEndpointAutoConfiguration

*  **EndpointAutoConfiguration**

公共配置，对于Web EndPoints与JMX EndPoints共用的配置。

@Configuration(proxyBeanMethods = false)
    public class EndpointAutoConfiguration {
    
       // 负责方法参数的转换的参数值映射器
       @Bean
       @ConditionalOnMissingBean
       public ParameterValueMapper endpointOperationParameterMapper(
           // 自动注入被@EndpointConverter标注的Converter与GenericConverter类型的bean
           // Spring Boot Actuator默认没有提供，可自定义添加
             @EndpointConverter ObjectProvider<Converter<?, ?>> converters,
             @EndpointConverter ObjectProvider<GenericConverter> genericConverters) {
          ConversionService conversionService = createConversionService(
                converters.orderedStream().collect(Collectors.toList()),
                genericConverters.orderedStream().collect(Collectors.toList()));
          return new ConversionServiceParameterValueMapper(conversionService);
       }
       // 参数转换器 
       private ConversionService createConversionService(List<Converter<?, ?>> converters,
             List<GenericConverter> genericConverters) {
          // 默认为空，满足if条件       
          if (genericConverters.isEmpty() && converters.isEmpty()) {
             // 添加Spring Boot默认提供的转换器 
             // ApplicationConversionService.getSharedInstance()也会调用new ApplicationConversionService();来添加默认提供的转换器
             return ApplicationConversionService.getSharedInstance();
          }
          // 如果有自定义的转换器，在自定义的基础上，加上Spring Boot默认提供的转化器
          ApplicationConversionService conversionService = new ApplicationConversionService();
          converters.forEach(conversionService::addConverter);
          genericConverters.forEach(conversionService::addConverter);
          return conversionService;
       }
    
       // 缓存切面，第一次访问后，会将结果缓存起来。下一次再获取直接从缓存中取
       // 可以设置缓存失效时间
       @Bean
       @ConditionalOnMissingBean
       public CachingOperationInvokerAdvisor endpointCachingOperationInvokerAdvisor(Environment environment) {
          return new CachingOperationInvokerAdvisor(new EndpointIdTimeToLivePropertyFunction(environment));
       }
    
    }

自定义转化器：

@Configuration
    public class CustomConversionConfiguration{
    
        /**
         * 自定义Converter
         * Converter接口是org.springframework.core.convert.converter.Converter
         *
         * 将Integer类型的值转换成String类型
         *
         */
        @Bean
        // 加上注解标注给EndPoint提供服务
        @EndpointConverter
        public Converter<Integer, String> customConverter() {
            return new CustomConverter();
        }
    
        static class CustomConverter implements Converter<Integer, String>{
            @Override
            public String convert(Integer source) {
                if (source == null) {
                    return null;
                }
                return source.toString();
            }
        }
    
        /**
         *
         * 自定义GenericConverter
         * GenericConverter接口是：org.springframework.core.convert.converter.GenericConverter
         *
         * @return
         */
        @Bean
        // 加上注解标注给EndPoint提供服务
        @EndpointConverter
        public GenericConverter customGenericConverter() {
            return new GenericConverter() {
                @Override
                public Set<ConvertiblePair> getConvertibleTypes() {
                    Set<ConvertiblePair> convertiblePairSet = new HashSet<>(2);
                    // 将Integer类型的值转换成String类型的值
                    convertiblePairSet.add(new ConvertiblePair(Integer.class, String.class));
                    return convertiblePairSet;
                }
    
                @Override
                public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
                    // 实现自定义逻辑
    
                    return null;
                }
            };
        }
    
    }

*  **JmxEndpointAutoConfiguration**

用于JMX EndPoints构建的相关配置。

@Configuration(proxyBeanMethods = false)
    @AutoConfigureAfter(JmxAutoConfiguration.class)
    // JmxEndpointProperties：management.endpoints.jmx前缀的配置
    @EnableConfigurationProperties(JmxEndpointProperties.class)
    // 通过配置 spring.jmx.enabled=false关闭JMX Endpoints功能
    @ConditionalOnProperty(prefix = "spring.jmx", name = "enabled", havingValue = "true")
    public class JmxEndpointAutoConfiguration {
    
       private final ApplicationContext applicationContext;
    
       private final JmxEndpointProperties properties;
       // 构造器注入
       public JmxEndpointAutoConfiguration(ApplicationContext applicationContext, JmxEndpointProperties properties) {
          this.applicationContext = applicationContext;
          this.properties = properties;
       }
    
       // 创建JmxEndpointDiscoverer
       // 根据@EndPoint、@JmxEndPoint标注的类
       @Bean
       @ConditionalOnMissingBean(JmxEndpointsSupplier.class)
       public JmxEndpointDiscoverer jmxAnnotationEndpointDiscoverer(ParameterValueMapper parameterValueMapper,
             ObjectProvider<OperationInvokerAdvisor> invokerAdvisors,
             ObjectProvider<EndpointFilter<ExposableJmxEndpoint>> filters) {
          return new JmxEndpointDiscoverer(this.applicationContext, parameterValueMapper,
                invokerAdvisors.orderedStream().collect(Collectors.toList()),
                filters.orderedStream().collect(Collectors.toList()));
       }
    
       // 创建和暴露JMX服务
       // 参数jmxEndpointsSupplier会自动注入JmxEndpointDiscoverer
       @Bean
       @ConditionalOnSingleCandidate(MBeanServer.class)
       public JmxEndpointExporter jmxMBeanExporter(MBeanServer mBeanServer, Environment environment,
             ObjectProvider<ObjectMapper> objectMapper, JmxEndpointsSupplier jmxEndpointsSupplier) {
          String contextId = ObjectUtils.getIdentityHexString(this.applicationContext);
          EndpointObjectNameFactory objectNameFactory = new DefaultEndpointObjectNameFactory(this.properties, environment,
                mBeanServer, contextId);
          JmxOperationResponseMapper responseMapper = new JacksonJmxOperationResponseMapper(
                objectMapper.getIfAvailable());
          return new JmxEndpointExporter(mBeanServer, objectNameFactory, responseMapper,
                jmxEndpointsSupplier.getEndpoints());
    
       }
       
       // EndPoint jmx服务暴露过滤器
       // 根据配置：management.endpoints.jmx.exposure.include 设置暴露服务
       // 根据配置：management.endpoints.jmx.exposure.exclude 设置不暴露服务
       @Bean
       public ExposeExcludePropertyEndpointFilter<ExposableJmxEndpoint> jmxIncludeExcludePropertyEndpointFilter() {
          JmxEndpointProperties.Exposure exposure = this.properties.getExposure();
          // 默认暴露所有服务
          return new ExposeExcludePropertyEndpointFilter<>(ExposableJmxEndpoint.class, exposure.getInclude(),
                exposure.getExclude(), "*");
       }
    
    }

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# **█ 创建和暴露服务** #

在配置类**JmxEndpointAutoConfiguration**中创建**JmxEndpointExporter**时：

@Bean
    @ConditionalOnSingleCandidate(MBeanServer.class)
    public JmxEndpointExporter jmxMBeanExporter(MBeanServer mBeanServer, Environment environment,
          ObjectProvider<ObjectMapper> objectMapper, JmxEndpointsSupplier jmxEndpointsSupplier) {
       String contextId = ObjectUtils.getIdentityHexString(this.applicationContext);
       EndpointObjectNameFactory objectNameFactory = new DefaultEndpointObjectNameFactory(this.properties, environment,
             mBeanServer, contextId);
       JmxOperationResponseMapper responseMapper = new JacksonJmxOperationResponseMapper(
             objectMapper.getIfAvailable());
       return new JmxEndpointExporter(mBeanServer, objectNameFactory, responseMapper,
             jmxEndpointsSupplier.getEndpoints());
    
    }

### ** 创建过程：** ###

jmxEndpointsSupplier.getEndpoints()，jmxEndpointsSupplier会被自动注入**JmxEndpointExporter**，调用JmxEndpointExporter的getEndpoints，JmxEndpointExporter也是同样继承了**EndpointDiscoverer**，创建过程和**WebEndpointDiscoverer**一样，只是重写的createEndpoint创建的**ExposableEndpoint**类型不同，其返回**DiscoveredJmxEndpoint**类型：（关于WebEndpointDiscoverer创建过程，请戳《[WEB Endpoints][]》）

@Override
    protected ExposableJmxEndpoint createEndpoint(Object endpointBean, EndpointId id, boolean enabledByDefault,
          Collection<JmxOperation> operations) {
       return new DiscoveredJmxEndpoint(this, endpointBean, id, enabledByDefault, operations);
    }

## ##

### 暴露过程： ###

new JmxEndpointExporter

return new JmxEndpointExporter(mBeanServer, objectNameFactory, responseMapper,
             jmxEndpointsSupplier.getEndpoints());

（1）JmxEndpointExporter实现了**InitializingBean**接口，会在Spring初始化Bean的时候，调用afterPropertiesSet方法：

@Override
    public void afterPropertiesSet() {
       this.registered = register();
    }

（2）register

private Collection<ObjectName> register() {
       return this.endpoints.stream().map(this::register).collect(Collectors.toList());
    }

this::register使用的是java8提供的新特性方法引用，即调用**JmxEndpointExporter**的有参方法register，参数是endpoints集合中的元素，是**DiscoveredJmxEndpoint**类型。

（3）register(endpoint)

// JmxEndpointExporter#register
    private ObjectName register(ExposableJmxEndpoint endpoint) {
       // endpoint是DiscoveredJmxEndpoint 
       Assert.notNull(endpoint, "Endpoint must not be null");
       try {
          ObjectName name = this.objectNameFactory.getObjectName(endpoint);
          // 创建MBean
          EndpointMBean mbean = new EndpointMBean(this.responseMapper, this.classLoader, endpoint);
          // 注册MBean
          this.mBeanServer.registerMBean(mbean, name);
          return name;
       }
       catch (MalformedObjectNameException ex) {
          throw new IllegalStateException("Invalid ObjectName for " + getEndpointDescription(endpoint), ex);
       }
       catch (Exception ex) {
          throw new MBeanExportException("Failed to register MBean for " + getEndpointDescription(endpoint), ex);
       }
    }

this.mBeanServer.registerMBean(mbean, name); 这边属于调用JDK提供的API了。

[Link 1]: https://blog.csdn.net/weixin_50518271/article/details/111183826
[WEB Endpoints]: https://blog.csdn.net/weixin_50518271/article/details/111237298
[Link 2]: https://baike.baidu.com/item/%E6%A4%8D%E5%85%A5/7958584