dubbo spring cloud dynamic service discovery

spring-cloud-alibaba-dubbo/src/main/java/com/alibaba/cloud/dubbo/metadata/repository/DubboServiceMetadataRepository.java

@@ -43,7 +43,6 @@ import java.util.stream.Stream;
 import javax.annotation.PostConstruct;
 
 import org.apache.dubbo.common.URL;
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.SmartInitializingSingleton;
@@ -70,6 +69,7 @@ import com.alibaba.cloud.dubbo.service.DubboMetadataService;
 import com.alibaba.cloud.dubbo.service.DubboMetadataServiceExporter;
 import com.alibaba.cloud.dubbo.service.DubboMetadataServiceProxy;
 import com.alibaba.cloud.dubbo.util.JSONUtils;
+
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.type.TypeFactory;
 
@@ -291,6 +291,16 @@ public class DubboServiceMetadataRepository
 		}
 	}
 
+	/**
+	 * Remove the metadata of Dubbo Services if no there is no service instance
+	 * @param serviceName the service name
+	 */
+	public void removeInitializedService(String serviceName) {
+		synchronized (monitor) {
+			initializedServices.remove(serviceName);
+		}
+	}
+
 	/**
 	 * Get the metadata {@link Map} of {@link DubboMetadataService}
 	 *
@@ -565,7 +575,7 @@ public class DubboServiceMetadataRepository
 		if (object == null) {
 			if (logger.isWarnEnabled()) {
 				logger.warn(
-						"DubboServiceMetadata can't be found in the Spring application [%s] and %s",
+						"DubboServiceMetadata can't be found in the Spring application [{}] and {}",
 						serviceName, requestMetadata);
 			}
 		}
@@ -640,6 +650,10 @@ public class DubboServiceMetadataRepository
 		dubboMetadataConfigServiceProxy.initProxy(serviceName, version);
 	}
 
+	public void removeServiceMetadata(String serviceName) {
+		dubboRestServiceMetadataRepository.remove(serviceName);
+	}
+
 	@Override
 	public void setApplicationEventPublisher(
 			ApplicationEventPublisher applicationEventPublisher) {

spring-cloud-alibaba-dubbo/src/main/java/com/alibaba/cloud/dubbo/registry/AbstractSpringCloudRegistry.java

@@ -40,7 +40,6 @@ import org.apache.dubbo.common.URL;
 import org.apache.dubbo.registry.NotifyListener;
 import org.apache.dubbo.registry.RegistryFactory;
 import org.apache.dubbo.registry.support.FailbackRegistry;
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.cloud.client.ServiceInstance;
@@ -215,6 +214,33 @@ public abstract class AbstractSpringCloudRegistry extends FailbackRegistry {
 					generateId(url), serviceName);
 		}
 
+		List<URL> allSubscribedURLs = new LinkedList<>();
+
+		Collection<ServiceInstance> serviceInstances = serviceInstancesFunction
+				.apply(serviceName);
+
+		if (CollectionUtils.isEmpty(serviceInstances)) {
+			dubboMetadataConfigServiceProxy.removeProxy(serviceName);
+			repository.removeInitializedService(serviceName);
+			repository.removeServiceMetadata(serviceName);
+			if (logger.isWarnEnabled()) {
+				logger.warn(
+						"There is no instance from service[name : {}], and then Dubbo Service[key : {}] will not be "
+								+ "available , please make sure the further impact",
+						serviceName, url.getServiceKey());
+			}
+			/**
+			 * URLs with {@link RegistryConstants#EMPTY_PROTOCOL}
+			 */
+			allSubscribedURLs.addAll(emptyURLs(url));
+			if (logger.isDebugEnabled()) {
+				logger.debug("The subscribed URL[{}] will notify all URLs : {}", url,
+						allSubscribedURLs);
+			}
+			listener.notify(allSubscribedURLs);
+			return;
+		}
+
 		DubboMetadataService dubboMetadataService = dubboMetadataConfigServiceProxy
 				.getProxy(serviceName);
 
@@ -239,50 +265,30 @@ public abstract class AbstractSpringCloudRegistry extends FailbackRegistry {
 			return;
 		}
 
-		Collection<ServiceInstance> serviceInstances = serviceInstancesFunction
+		List<URL> exportedURLs = getExportedURLs(dubboMetadataService, url);
-				.apply(serviceName);
+
-
+		for (URL exportedURL : exportedURLs) {
-		List<URL> allSubscribedURLs = new LinkedList<>();
+			String protocol = exportedURL.getProtocol();
-
+			List<URL> subscribedURLs = new LinkedList<>();
-		if (CollectionUtils.isEmpty(serviceInstances)) {
+			serviceInstances.forEach(serviceInstance -> {
-			if (logger.isWarnEnabled()) {
+				Integer port = repository.getDubboProtocolPort(serviceInstance, protocol);
-				logger.warn(
+				String host = serviceInstance.getHost();
-						"There is no instance from service[name : {}], and then Dubbo Service[key : {}] will not be "
+				if (port == null) {
-								+ "available , please make sure the further impact",
+					if (logger.isWarnEnabled()) {
-						serviceName, url.getServiceKey());
+						logger.warn(
-			}
+								"The protocol[{}] port of Dubbo  service instance[host : {}] "
-			/**
+										+ "can't be resolved",
-			 * URLs with {@link RegistryConstants#EMPTY_PROTOCOL}
+								protocol, host);
-			 */
-			allSubscribedURLs.addAll(emptyURLs(url));
-		}
-		else {
-			List<URL> exportedURLs = getExportedURLs(dubboMetadataService, url);
-
-			for (URL exportedURL : exportedURLs) {
-				String protocol = exportedURL.getProtocol();
-				List<URL> subscribedURLs = new LinkedList<>();
-				serviceInstances.forEach(serviceInstance -> {
-					Integer port = repository.getDubboProtocolPort(serviceInstance,
-							protocol);
-					String host = serviceInstance.getHost();
-					if (port == null) {
-						if (logger.isWarnEnabled()) {
-							logger.warn(
-									"The protocol[{}] port of Dubbo  service instance[host : {}] "
-											+ "can't be resolved",
-									protocol, host);
-						}
-					}
-					else {
-						URL subscribedURL = new URL(protocol, host, port,
-								exportedURL.getParameters());
-						subscribedURLs.add(subscribedURL);
 					}
-				});
+				}
-
+				else {
-				allSubscribedURLs.addAll(subscribedURLs);
+					URL subscribedURL = new URL(protocol, host, port,
-			}
+							exportedURL.getParameters());
+					subscribedURLs.add(subscribedURL);
+				}
+			});
+
+			allSubscribedURLs.addAll(subscribedURLs);
 		}
 
 		if (logger.isDebugEnabled()) {

spring-cloud-alibaba-dubbo/src/main/java/com/alibaba/cloud/dubbo/service/DubboMetadataServiceProxy.java

@@ -52,6 +52,14 @@ public class DubboMetadataServiceProxy implements BeanClassLoaderAware, Disposab
 				name -> newProxy(name, version));
 	}
 
+    /**
+     * Remove {@link DubboMetadataService}'s Proxy by service name
+     * @param serviceName the service name
+     */
+	public void removeProxy(String serviceName) {
+		dubboMetadataServiceCache.remove(serviceName);
+	}
+
 	/**
 	 * Get a proxy instance of {@link DubboMetadataService} via the specified service name
 	 *