content: /*
   * Copyright 2013-2023 the original author or authors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      https://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.alibaba.cloud.nacos.discovery;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.Optional;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.springframework.beans.factory.annotation.Value;
  import org.springframework.cloud.client.ServiceInstance;
  import org.springframework.cloud.client.discovery.DiscoveryClient;
  
  /**
   * @author xiaojing
   * @author renhaojun
   * @author echooymxq
   * @author freeman
   */
  public class NacosDiscoveryClient implements DiscoveryClient {
  
  	private static final Logger log = LoggerFactory.getLogger(NacosDiscoveryClient.class);
  
  	/**
  	 * Nacos Discovery Client Description.
  	 */
  	public static final String DESCRIPTION = "Spring Cloud Nacos Discovery Client";
  
  	private NacosServiceDiscovery serviceDiscovery;
  
  	@Value("${spring.cloud.nacos.discovery.failure-tolerance-enabled:false}")
  	private boolean failureToleranceEnabled;
  
  	public NacosDiscoveryClient(NacosServiceDiscovery nacosServiceDiscovery) {
  		this.serviceDiscovery = nacosServiceDiscovery;
  	}
  
  	@Override
  	public String description() {
  		return DESCRIPTION;
  	}
  
  	@Override
  	public List<ServiceInstance> getInstances(String serviceId) {
  		try {
  			return Optional.of(serviceDiscovery.getInstances(serviceId))
  					.map(instances -> {
  						ServiceCache.setInstances(serviceId, instances);
  						return instances;
  					}).get();
  		}
  		catch (Exception e) {
  			if (failureToleranceEnabled) {
  				return ServiceCache.getInstances(serviceId);
  			}
  			throw new RuntimeException(
  					"Can not get hosts from nacos server. serviceId: " + serviceId, e);
  		}
  	}
  
  	@Override
  	public List<String> getServices() {
  		try {
  			return Optional.of(serviceDiscovery.getServices()).map(services -> {
  				ServiceCache.setServiceIds(services);
  				return services;
  			}).get();
  		}
  		catch (Exception e) {
  			log.error("get service name from nacos server failed.", e);
  			return failureToleranceEnabled ? ServiceCache.getServiceIds()
  					: Collections.emptyList();
  		}
  	}
  
  }
  