技術文章 » 一個 dubbo 和 springboot 的相容性問題

一個 dubbo 和 springboot 的相容性問題

2022-10-03 21:00:30

背景介紹

最近把dubbo的版本從2.7.3升級到2.7.15時，遇到一個報錯 No application config found or it's not a valid config! ，對應的異常棧為：

Caused by: java.lang.IllegalStateException: No application config found or it's not a valid config! Please add <dubbo:application name="..." /> to your spring config.
	at org.apache.dubbo.config.utils.ConfigValidationUtils.validateApplicationConfig(ConfigValidationUtils.java:419) ~[dubbo-2.7.15.jar:2.7.15]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.checkGlobalConfigs(DubboBootstrap.java:539) ~[dubbo-2.7.15.jar:2.7.15]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.initialize(DubboBootstrap.java:525) ~[dubbo-2.7.15.jar:2.7.15]
	at org.apache.dubbo.config.ReferenceConfig.init(ReferenceConfig.java:244) ~[dubbo-2.7.15.jar:2.7.15]
	at org.apache.dubbo.config.ReferenceConfig.get(ReferenceConfig.java:206) ~[dubbo-2.7.15.jar:2.7.15]
	at org.apache.dubbo.config.spring.ReferenceBean.getObject(ReferenceBean.java:68) ~[dubbo-2.7.15.jar:2.7.15]
	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:171) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:101) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1818) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getObjectForBeanInstance(AbstractAutowireCapableBeanFactory.java:1266) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:260) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:207) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.resolveBeanByName(AbstractAutowireCapableBeanFactory.java:454) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource(CommonAnnotationBeanPostProcessor.java:543) ~[spring-context-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor.java:513) ~[spring-context-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(CommonAnnotationBeanPostProcessor.java:653) ~[spring-context-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:224) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:116) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:334) ~[spring-context-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1429) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:400) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1338) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:874) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:778) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:528) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1338) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:207) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.aop.framework.autoproxy.BeanFactoryAdvisorRetrievalHelper.findAdvisorBeans(BeanFactoryAdvisorRetrievalHelper.java:91) ~[spring-aop-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.findCandidateAdvisors(AbstractAdvisorAutoProxyCreator.java:109) ~[spring-aop-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator.findCandidateAdvisors(AnnotationAwareAspectJAutoProxyCreator.java:92) ~[spring-aop-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.aop.aspectj.autoproxy.AspectJAwareAdvisorAutoProxyCreator.shouldSkip(AspectJAwareAdvisorAutoProxyCreator.java:101) ~[spring-aop-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.postProcessBeforeInstantiation(AbstractAutoProxyCreator.java:251) ~[spring-aop-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInstantiation(AbstractAutowireCapableBeanFactory.java:1141) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.resolveBeforeInstantiation(AbstractAutowireCapableBeanFactory.java:1114) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:506) ~[spring-beans-5.2.0.RELEASE.jar:5.2.0.RELEASE]
	... 12 more

　　

​其中，我們使用 Springboot 版本是2.2.0。

 

於是手動跟蹤偵錯了下，發現某些後置處理器執行時，在解決它的依賴時，會去建立 dubbo 服務的 bean，然後就會建立 ApplicationConfig 物件了。注意這個物件其實只是new了一下，所有屬性都是預設值，並非來源於我們定義的 dubbo 組態檔。

 

而我們定義的 dubbo 組態檔，是在 ApplicationConfig 中的 addIntoConfigManager 中注入的：

    public abstract class AbstractConfig implements Serializable {
      ...
      
      @PostConstruct
      public void addIntoConfigManager() {
          ApplicationModel.getConfigManager().addConfig(this);
      }
      
      ...
    }

　　

其中，@PostConstruct 註解會由 CommonAnnotationBeanPostProcessor 這個後置處理器（繼承自 InitDestroyAnnotationBeanPostProcessor）解析執行。但很遺憾，此時它還沒有被執行，因此也就沒有把正確的dubbo設定注入進去，最終導致dubbo框架在校驗時發現無效設定，繼而報錯。

 

網上相關討論及解決方案

關於這類報錯，網上也有不少討論，如：

 

簡單總結起來，由於dubbo沒有一個固定的初始化時機，而是與 ReferenceBean 等 dubbo 框架中的 beans 初始化相關。 如果它們被過早初始化，導致某些 BeanPostProcessor 尚未被執行，就會出現dubbo設定丟失的問題。

 

自然，dubbo官方也注意到了這個問題，於是在3.x版本進行了改造，針對該問題做了優化，參見Dubbo 3 Spring相關優化。

 

但3.x做了大量重構，如果我們不想升級，應該怎麼辦呢？

其實根據上面提到的原因，我們可以自己定義一個後置處理器，攔截 dubbo 框架的 beans，並手動注入對應的設定。本質上來說，將之前來不及執行的注入程式碼提到前面去。這樣，我們前面提到的「某些後置處理器執行時，在解決它的依賴時，會去建立 dubbo 服務的 bean，然後就會建立 ApplicationConfig 物件了」，就變成了「某些後置處理器執行時，在解決它的依賴時，會去建立 dubbo 服務的 bean，此時會被我們自定義的後置處理器攔截，並注入對應的dubbo設定，然後就會建立正確的 ApplicationConfig 物件」。

 

具體做法為：

step1. 定義一個後置處理器，識別到 bean 屬於 AbstractConfig 設定後，將其注入：

package com.xxx;

import org.apache.dubbo.config.AbstractConfig;
import org.apache.dubbo.rpc.model.ApplicationModel;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

public class DubboBeanPostProcessor implements BeanPostProcessor {

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof AbstractConfig) {
            AbstractConfig abstractConfig = (AbstractConfig) bean;
            ApplicationModel.getConfigManager().addConfig(abstractConfig);
        }
        return BeanPostProcessor.super.postProcessAfterInitialization(bean, beanName);
    }
}

　　

step2. 定義一個 Initializer，並將剛才定義的 DubboBeanPostProcessor 注入：

package com.xxx;

import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;

public class DubboApplicationContextInitializer
        implements ApplicationContextInitializer<ConfigurableApplicationContext> {

    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        applicationContext.getBeanFactory().addBeanPostProcessor(new DubboBeanPostProcessor());
    }
}

　　

step3. 把 DubboApplicationContextInitializer 注入到Spring框架中，可以採用多種方式。

方式1. 直接在啟動類注入：

@ImportResource(locations = {"classpath:dubbo.xml"})
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class Launcher extends SpringBootServletInitializer {

    public static void main(String[] args) {
        SpringApplication springApplication = new SpringApplication(Launcher.class);
        springApplication.addInitializers(new DubboApplicationContextInitializer());
        springApplication.run(args);
    }
}

方式2. 在 resources 的 META-INF 目錄下設定 spring.factories 檔案並寫入：

org.springframework.context.ApplicationContextInitializer=com.xxx.DubboApplicationContextInitializer