聊聊dubbo-spring-boot的DubboShutdownMetadata

序

本文主要研究一下 dubbo spring boot 的 DubboShutdownMetadata

AbstractDubboMetadata

dubbo-spring-boot-project-2.7.3/dubbo-spring-boot-compatible/actuator/src/main/java/org/apache/dubbo/spring/boot/actuate/endpoint/metadata/AbstractDubboMetadata.java

public abstract class AbstractDubboMetadata implements ApplicationContextAware, EnvironmentAware {

    protected ApplicationContext applicationContext;

    protected ConfigurableEnvironment environment;

    private static boolean isSimpleType(Class<?> type) {return isPrimitiveOrWrapper(type)
                || type == String.class
                || type == BigDecimal.class
                || type == BigInteger.class
                || type == Date.class
                || type == URL.class
                || type == Class.class
                ;
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;}

    @Override
    public void setEnvironment(Environment environment) {if (environment instanceof ConfigurableEnvironment) {this.environment = (ConfigurableEnvironment) environment;
        }
    }

    protected Map<String, Object> resolveBeanMetadata(final Object bean) {final Map<String, Object> beanMetadata = new LinkedHashMap<>();

        try {BeanInfo beanInfo = Introspector.getBeanInfo(bean.getClass());
            PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();

            for (PropertyDescriptor propertyDescriptor : propertyDescriptors) {Method readMethod = propertyDescriptor.getReadMethod();

                if (readMethod != null && isSimpleType(propertyDescriptor.getPropertyType())) {String name = Introspector.decapitalize(propertyDescriptor.getName());
                    Object value = readMethod.invoke(bean);

                    beanMetadata.put(name, value);
                }

            }

        } catch (Exception e) {throw new RuntimeException(e);
        }

        return beanMetadata;

    }

    protected Map<String, ServiceBean> getServiceBeansMap() {return beansOfTypeIncludingAncestors(applicationContext, ServiceBean.class);
    }

    protected ReferenceAnnotationBeanPostProcessor getReferenceAnnotationBeanPostProcessor() {return applicationContext.getBean(BEAN_NAME, ReferenceAnnotationBeanPostProcessor.class);
    }

    protected Map<String, ProtocolConfig> getProtocolConfigsBeanMap() {return beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class);
    }


}

• AbstractDubboMetadata 声明实现了 ApplicationContextAware 及 EnvironmentAware 接口；提供了 getServiceBeansMap、getReferenceAnnotationBeanPostProcessor、getProtocolConfigsBeanMap 实现类使用

DubboShutdownMetadata

dubbo-spring-boot-project-2.7.3/dubbo-spring-boot-compatible/actuator/src/main/java/org/apache/dubbo/spring/boot/actuate/endpoint/metadata/DubboShutdownMetadata.java

@Component
public class DubboShutdownMetadata extends AbstractDubboMetadata {public Map<String, Object> shutdown() throws Exception {Map<String, Object> shutdownCountData = new LinkedHashMap<>();

        // registries
        int registriesCount = getRegistries().size();

        // protocols
        int protocolsCount = getProtocolConfigsBeanMap().size();

        shutdownCountData.put("registries", registriesCount);
        shutdownCountData.put("protocols", protocolsCount);

        // Service Beans
        Map<String, ServiceBean> serviceBeansMap = getServiceBeansMap();
        if (!serviceBeansMap.isEmpty()) {for (ServiceBean serviceBean : serviceBeansMap.values()) {serviceBean.destroy();
            }
        }
        shutdownCountData.put("services", serviceBeansMap.size());

        // Reference Beans
        ReferenceAnnotationBeanPostProcessor beanPostProcessor = getReferenceAnnotationBeanPostProcessor();

        int referencesCount = beanPostProcessor.getReferenceBeans().size();

        beanPostProcessor.destroy();

        shutdownCountData.put("references", referencesCount);

        // Set Result to complete
        Map<String, Object> shutdownData = new TreeMap<>();
        shutdownData.put("shutdown.count", shutdownCountData);


        return shutdownData;
    }

}

• DubboShutdownMetadata 继承了 AbstractDubboMetadata，它提供了 shutdown 方法，该方法会遍历 getServiceBeansMap，挨个执行 serviceBean.destroy() 方法，最后执行 ReferenceAnnotationBeanPostProcessor.destroy 方法

ReferenceAnnotationBeanPostProcessor

dubbo-2.7.3-sources.jar!/org/apache/dubbo/config/spring/beans/factory/annotation/ReferenceAnnotationBeanPostProcessor.java

public class ReferenceAnnotationBeanPostProcessor extends AnnotationInjectedBeanPostProcessor implements
        ApplicationContextAware, ApplicationListener {

    /**
     * The bean name of {@link ReferenceAnnotationBeanPostProcessor}
     */
    public static final String BEAN_NAME = "referenceAnnotationBeanPostProcessor";

    /**
     * Cache size
     */
    private static final int CACHE_SIZE = Integer.getInteger(BEAN_NAME + ".cache.size", 32);

    private final ConcurrentMap<String, ReferenceBean<?>> referenceBeanCache =
            new ConcurrentHashMap<>(CACHE_SIZE);

    private final ConcurrentHashMap<String, ReferenceBeanInvocationHandler> localReferenceBeanInvocationHandlerCache =
            new ConcurrentHashMap<>(CACHE_SIZE);

    private final ConcurrentMap<InjectionMetadata.InjectedElement, ReferenceBean<?>> injectedFieldReferenceBeanCache =
            new ConcurrentHashMap<>(CACHE_SIZE);

    private final ConcurrentMap<InjectionMetadata.InjectedElement, ReferenceBean<?>> injectedMethodReferenceBeanCache =
            new ConcurrentHashMap<>(CACHE_SIZE);

    private ApplicationContext applicationContext;

    /**
     * To support the legacy annotation that is @com.alibaba.dubbo.config.annotation.Reference since 2.7.3
     */
    public ReferenceAnnotationBeanPostProcessor() {super(Reference.class, com.alibaba.dubbo.config.annotation.Reference.class);
    }

    //......

    @Override
    public void destroy() throws Exception {super.destroy();
        this.referenceBeanCache.clear();
        this.localReferenceBeanInvocationHandlerCache.clear();
        this.injectedFieldReferenceBeanCache.clear();
        this.injectedMethodReferenceBeanCache.clear();}

}

• ReferenceAnnotationBeanPostProcessor 继承了 AnnotationInjectedBeanPostProcessor，实现了 ApplicationContextAware, ApplicationListener 接口；destroy 方法会执行 AnnotationInjectedBeanPostProcessor.destroy，然后清空 referenceBeanCache、localReferenceBeanInvocationHandlerCache、injectedFieldReferenceBeanCache、injectedMethodReferenceBeanCache

小结

DubboShutdownMetadata 继承了 AbstractDubboMetadata，它提供了 shutdown 方法，该方法会遍历 getServiceBeansMap，挨个执行 serviceBean.destroy() 方法，最后执行 ReferenceAnnotationBeanPostProcessor.destroy 方法

doc

• DubboShutdownMetadata