Dubbo 2.7.3支持配置中心外部化配置， 因此只需要定义一个ConfigCenterConfig的Bean。
@EnableDubbo(scanBasePackages = {"com.slankka.cloud.dubbo"}) @Configuration public class DubboConfig { @Bean public ConfigCenterConfig configCenterConfig() { ConfigCenterConfig configCenterConfig = new ConfigCenterConfig(); configCenterConfig.setAddress("apollo.xxxxx.com:8080"); configCenterConfig.setProtocol("apollo"); configCenterConfig.setNamespace("dubbo"); configCenterConfig.setGroup(null); return configCenterConfig; } }
问题：
- Apollo 找不到 meta。
- Dubbo 找不到 provider
- Apollo 找不到meta，Apollo的jar 的apollo-core的配置文件明明声明了PRO.meta="apollo.xxxxx.com:8080"。这个问题出现在
apollo.bootstrap.enabled = false
如果要坚持这样配置，需要增加
apollo.meta=apollo.xxxxx.com:8080
- Dubbo 找不到Provider，仔细看日志 Interface: com.xxx.xxx.service，如果后面没有跟着版本号例如： 1.2.0，则说明版本没有定义。
问题是因为定义了占位符，而Dubbo启动的时候，创建ReferenceBean的类是个BeanPostProcessor，启动比较早，而apollo.bootstrap.enabled=false。
则Dubbo创建这个IRExecutionService对应的Bean类的时候，找不到version，但是他catch吃掉异常了。等于没有配置version。
apollo.bootstrap.enabled = false @Reference(version = "${job.service.version}", retries = 0, lazy = true) private IRExecutionService executionService;
则原因是Dubbo不能从ConfigCenterConfig读取版本配置，或者太迟了，如果要解决很简单 ，但是太依赖Apollo提前初始化开关。
package io.github.slankka.dubbo-apollo.server.config; import org.apache.dubbo.common.URL; import org.apache.dubbo.common.config.Configuration; import org.apache.dubbo.common.config.Environment; import org.apache.dubbo.common.extension.ExtensionLoader; import org.apache.dubbo.common.utils.StringUtils; import org.apache.dubbo.config.ApplicationConfig; import org.apache.dubbo.config.ConfigCenterConfig; import org.apache.dubbo.config.spring.beans.factory.annotation.ReferenceAnnotationBeanPostProcessor; import org.apache.dubbo.configcenter.DynamicConfiguration; import org.apache.dubbo.configcenter.DynamicConfigurationFactory; import org.springframework.beans.BeansException; import org.springframework.beans.factory.annotation.InjectionMetadata; import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty; import org.springframework.boot.context.properties.bind.PropertySourcesPlaceholdersResolver; import org.springframework.context.ApplicationContext; import org.springframework.core.annotation.AnnotationAttributes; import org.springframework.core.env.PropertySource; import org.springframework.stereotype.Component; import java.io.IOException; import java.util.ArrayList; import java.util.List; import static org.apache.dubbo.common.config.ConfigurationUtils.parseProperties; /** * Project: dubbo-apollo * * @author slankka on 2019/8/29. */ @ConditionalOnProperty(name = "apollo.bootstrap.enabled", havingValue = "false", matchIfMissing = true) @Component(value = ReferenceAnnotationBeanPostProcessor.BEAN_NAME) public class ReferencedAnnotationPatch extends ReferenceAnnotationBeanPostProcessor { private ApplicationContext myContext; @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { myContext = applicationContext; super.setApplicationContext(applicationContext); } @Override protected Object doGetInjectedBean(AnnotationAttributes attributes, Object bean, String beanName, Class<?> injectedType, InjectionMetadata.InjectedElement injectedElement) throws Exception { eagerInitConfigCenter(); Configuration configuration = Environment.getInstance().getConfiguration(); List<PropertySource<?>> propertySources = new ArrayList<>(); propertySources.add(new PropertySource<Configuration>("dubboConfigCenter", configuration) { @Override public Object getProperty(String name) { return configuration.getProperty(name); } }); PropertySourcesPlaceholdersResolver propertySourcesPlaceholdersResolver = new PropertySourcesPlaceholdersResolver(propertySources); for (String attribute : attributes.keySet()) { Object stringAttr = attributes.get(attribute); if (stringAttr instanceof String) { Object value = propertySourcesPlaceholdersResolver.resolvePlaceholders(attributes.getString(attribute)); attributes.put(attribute, value); } } return super.doGetInjectedBean(attributes, bean, beanName, injectedType, injectedElement); } private void eagerInitConfigCenter() { ConfigCenterConfig configCenter = myContext.getBean(ConfigCenterConfig.class); if (configCenter.isValid()) { if (configCenter.checkOrUpdateInited()) { configCenter.refresh(); URL url = configCenter.toUrl(); DynamicConfigurationFactory factories = ExtensionLoader .getExtensionLoader(DynamicConfigurationFactory.class) .getExtension(url.getProtocol()); DynamicConfiguration dynamicConfiguration = factories.getDynamicConfiguration(url); String configContent = dynamicConfiguration.getProperties(configCenter.getConfigFile(), configCenter.getGroup()); ApplicationConfig application = myContext.getBean(ApplicationConfig.class); String appGroup = application.getName(); String appConfigContent = null; if (StringUtils.isNotEmpty(appGroup)) { appConfigContent = dynamicConfiguration.getProperties (StringUtils.isNotEmpty(configCenter.getAppConfigFile()) ? configCenter.getAppConfigFile() : configCenter.getConfigFile(), appGroup ); } try { Environment.getInstance().setConfigCenterFirst(configCenter.isHighestPriority()); Environment.getInstance().updateExternalConfigurationMap(parseProperties(configContent)); Environment.getInstance().updateAppExternalConfigurationMap(parseProperties(appConfigContent)); } catch (IOException e) { throw new IllegalStateException("Failed to parse configurations from Config Center.", e); } } } } }
则能纠正Dubbo 的ReferenceAnnotationBeanPostProcessor 行为，因为这个时候，已经有ConfigCenterConfig这个Bean了，所以让ConfigCenter提前启动，从而使得@Reference注解的占位符能够被解析。
注意，这个占位符是配置在Namespace("dubbo");内的。
Dubbo 会默认读取 dubbo这个 Apollo的namespace，如果用自定义的namespace，他也会读取，因为不存在而启动减慢，所以为了加快启动速度，建议创建Apollo的 一个空dubbo的namespace。
来源：博客园
作者：一杯半盏
链接：https://www.cnblogs.com/slankka/p/11431324.html