content: /*
   * Copyright 1999-2025 Alibaba Group Holding Ltd.
   *
   * 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
   *
   *      http://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.nacos.client.address;
  
  import com.alibaba.nacos.api.PropertyKeyConst;
  import com.alibaba.nacos.api.SystemPropertyKeyConst;
  import com.alibaba.nacos.api.common.Constants;
  import com.alibaba.nacos.api.exception.NacosException;
  import com.alibaba.nacos.client.constant.Constants.Address;
  import com.alibaba.nacos.client.env.NacosClientProperties;
  import com.alibaba.nacos.client.utils.ClientBasicParamUtil;
  import com.alibaba.nacos.client.utils.ContextPathUtil;
  import com.alibaba.nacos.client.utils.TemplateUtils;
  import com.alibaba.nacos.common.executor.NameThreadFactory;
  import com.alibaba.nacos.common.http.HttpRestResult;
  import com.alibaba.nacos.common.http.HttpUtils;
  import com.alibaba.nacos.common.http.client.NacosRestTemplate;
  import com.alibaba.nacos.common.http.param.Query;
  import com.alibaba.nacos.common.notify.NotifyCenter;
  import com.alibaba.nacos.common.utils.CollectionUtils;
  import com.alibaba.nacos.common.utils.InternetAddressUtil;
  import com.alibaba.nacos.common.utils.IoUtils;
  import com.alibaba.nacos.common.utils.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.StringReader;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.ScheduledThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  /**
   * Endpoint server list provider.
   *
   * @author totalo
   */
  public class EndpointServerListProvider extends AbstractServerListProvider {
      
      private static final Logger LOGGER = LoggerFactory.getLogger(EndpointServerListProvider.class);
      
      private static final boolean USE_ENDPOINT_PARSING_RULE_DEFAULT_VALUE = true;
      
      private NacosRestTemplate nacosRestTemplate;
      
      private static final String CUSTOM_NAME = "custom";
      
      private final long refreshServerListInternal = TimeUnit.SECONDS.toMillis(30);
      
      private final int initServerListRetryTimes = 5;
      
      private long lastServerListRefreshTime = 0L;
      
      private ScheduledExecutorService refreshServerListExecutor;
      
      private String endpoint;
      
      private int endpointPort = 8080;
      
      private String endpointContextPath;
      
      private String serverListName = ClientBasicParamUtil.getDefaultNodesPath();
      
      private volatile List<String> serversFromEndpoint = new ArrayList<>();
      
      private String addressServerUrl;
      
      private String moduleName = "default";
      
      @Override
      public void init(final NacosClientProperties properties, final NacosRestTemplate nacosRestTemplate)
              throws NacosException {
          super.init(properties, nacosRestTemplate);
          this.nacosRestTemplate = nacosRestTemplate;
          initEndpoint(properties);
          initEndpointPort(properties);
          initEndpointContextPath(properties);
          initServerListName(properties);
          initAddressServerUrl(properties);
          initModuleName(properties);
          startRefreshServerListTask(properties);
      }
      
      @Override
      public List<String> getServerList() {
          return serversFromEndpoint;
      }
      
      @Override
      public String getServerName() {
          String contextPathTmp =
                  StringUtils.isNotBlank(this.endpointContextPath) ? this.endpointContextPath : this.contextPath;
          return CUSTOM_NAME + "-" + String.join("_", endpoint, String.valueOf(endpointPort), contextPathTmp,
                  serverListName) + (StringUtils.isNotBlank(namespace) ? ("_" + StringUtils.trim(namespace)) : "");
      }
      
      @Override
      public int getOrder() {
          return Address.ENDPOINT_SERVER_LIST_PROVIDER_ORDER;
      }
      
      @Override
      public boolean match(final NacosClientProperties properties) {
          String endpointTmp = getEndPointTmp(properties);
          return StringUtils.isNotBlank(endpointTmp);
      }
      
      @Override
      public String getAddressSource() {
          return this.addressServerUrl;
      }
      
      private String getEndPointTmp(NacosClientProperties properties) {
          String endpointTmp = properties.getProperty(PropertyKeyConst.ENDPOINT);
          String isUseEndpointRuleParsing = properties.getProperty(PropertyKeyConst.IS_USE_ENDPOINT_PARSING_RULE,
                  properties.getProperty(SystemPropertyKeyConst.IS_USE_ENDPOINT_PARSING_RULE,
                          String.valueOf(USE_ENDPOINT_PARSING_RULE_DEFAULT_VALUE)));
          if (Boolean.parseBoolean(isUseEndpointRuleParsing)) {
              endpointTmp = ClientBasicParamUtil.parsingEndpointRule(endpointTmp);
          }
          return endpointTmp;
      }
      
      /**
       * Start refresh server list task.
       *
       * @throws NacosException nacos exception
       */
      public void startRefreshServerListTask(NacosClientProperties properties) throws NacosException {
          for (int i = 0; i < initServerListRetryTimes && getServerList().isEmpty(); ++i) {
              refreshServerListIfNeed();
              if (!serversFromEndpoint.isEmpty()) {
                  break;
              }
              try {
                  this.wait((i + 1) * 100L);
              } catch (Exception e) {
                  LOGGER.warn("get serverlist fail,url: {}", addressServerUrl);
              }
          }
          
          if (serversFromEndpoint.isEmpty()) {
              LOGGER.error("[init-serverlist] fail to get NACOS-server serverlist! url: {}", addressServerUrl);
              throw new NacosException(NacosException.SERVER_ERROR,
                      "fail to get NACOS-server serverlist! not connnect url:" + addressServerUrl);
          }
          
          refreshServerListExecutor = new ScheduledThreadPoolExecutor(1,
                  new NameThreadFactory("com.alibaba.nacos.client.address.EndpointServerListProvider.refreshServerList"));
          // executor schedules the timer task
          long refreshInterval = Long.parseLong(
                  properties.getProperty(PropertyKeyConst.ENDPOINT_REFRESH_INTERVAL_SECONDS, "30"));
          refreshServerListExecutor.scheduleWithFixedDelay(this::refreshServerListIfNeed, 0L, refreshInterval,
                  TimeUnit.SECONDS);
      }
      
      private void refreshServerListIfNeed() {
          try {
              if (System.currentTimeMillis() - lastServerListRefreshTime < refreshServerListInternal) {
                  return;
              }
              List<String> list = getServerListFromEndpoint();
              if (CollectionUtils.isEmpty(list)) {
                  throw new Exception("Can not acquire Nacos list");
              }
              list.sort(String::compareTo);
              if (!CollectionUtils.isEqualCollection(list, serversFromEndpoint)) {
                  LOGGER.info("[SERVER-LIST] server list is updated: {}", list);
                  serversFromEndpoint = list;
                  lastServerListRefreshTime = System.currentTimeMillis();
                  NotifyCenter.publishEvent(new ServerListChangeEvent());
              }
          } catch (Throwable e) {
              LOGGER.warn("failed to update server list", e);
          }
      }
      
      private List<String> getServerListFromEndpoint() {
          try {
              HttpRestResult<String> httpResult = nacosRestTemplate.get(addressServerUrl,
                      HttpUtils.builderHeader(moduleName), Query.EMPTY, String.class);
              
              if (!httpResult.ok()) {
                  LOGGER.error("[check-serverlist] error. addressServerUrl: {}, code: {}", addressServerUrl,
                          httpResult.getCode());
                  return null;
              }
              List<String> lines = IoUtils.readLines(new StringReader(httpResult.getData()));
              List<String> result = new ArrayList<>(lines.size());
              for (String serverAddr : lines) {
                  String[] ipPort = InternetAddressUtil.splitIpPortStr(serverAddr);
                  String ip = ipPort[0].trim();
                  if (ipPort.length == 1) {
                      result.add(ip + InternetAddressUtil.IP_PORT_SPLITER + ClientBasicParamUtil.getDefaultServerPort());
                  } else {
                      result.add(serverAddr);
                  }
              }
              return result;
          } catch (Exception e) {
              LOGGER.error("[check-serverlist] exception. url: {}", addressServerUrl, e);
              return null;
          }
      }
      
      private void initEndpoint(NacosClientProperties properties) {
          // Endpoint should not be null or empty, because the match has return `true`.
          this.endpoint = getEndPointTmp(properties);
      }
      
      private void initEndpointPort(NacosClientProperties properties) {
          String endpointPortTmp = TemplateUtils.stringEmptyAndThenExecute(
                  properties.getProperty(PropertyKeyConst.SystemEnv.ALIBABA_ALIWARE_ENDPOINT_PORT),
                  () -> properties.getProperty(PropertyKeyConst.ENDPOINT_PORT));
          if (StringUtils.isNotBlank(endpointPortTmp)) {
              this.endpointPort = Integer.parseInt(endpointPortTmp);
          }
      }
      
      private void initEndpointContextPath(NacosClientProperties properties) {
          String endpointContextPathTmp = TemplateUtils.stringEmptyAndThenExecute(
                  properties.getProperty(PropertyKeyConst.SystemEnv.ALIBABA_ALIWARE_ENDPOINT_CONTEXT_PATH),
                  () -> properties.getProperty(PropertyKeyConst.ENDPOINT_CONTEXT_PATH));
          if (StringUtils.isNotBlank(endpointContextPathTmp)) {
              this.endpointContextPath = endpointContextPathTmp;
          }
      }
      
      private void initServerListName(NacosClientProperties properties) {
          String serverListNameTmp = properties.getProperty(PropertyKeyConst.ENDPOINT_CLUSTER_NAME);
          boolean isUseClusterName = Boolean.parseBoolean(
                  properties.getProperty(PropertyKeyConst.IS_ADAPT_CLUSTER_NAME_USAGE));
          if (StringUtils.isBlank(serverListNameTmp) && isUseClusterName) {
              serverListNameTmp = properties.getProperty(PropertyKeyConst.CLUSTER_NAME);
          }
          if (!StringUtils.isBlank(serverListNameTmp)) {
              this.serverListName = serverListNameTmp;
          }
      }
      
      private void initAddressServerUrl(NacosClientProperties properties) {
          String contextPathTmp = StringUtils.isNotBlank(this.endpointContextPath) ? ContextPathUtil.normalizeContextPath(
                  this.endpointContextPath) : ContextPathUtil.normalizeContextPath(this.contextPath);
          StringBuilder addressServerUrlTem = new StringBuilder(
                  String.format("http://%s:%d%s/%s", this.endpoint, this.endpointPort, contextPathTmp,
                          this.serverListName));
          boolean hasQueryString = false;
          if (StringUtils.isNotBlank(namespace)) {
              addressServerUrlTem.append("?namespace=").append(namespace);
              hasQueryString = true;
          }
          if (properties.containsKey(PropertyKeyConst.ENDPOINT_QUERY_PARAMS)) {
              addressServerUrlTem.append(hasQueryString ? "&" : "?");
              addressServerUrlTem.append(properties.getProperty(PropertyKeyConst.ENDPOINT_QUERY_PARAMS));
          }
          this.addressServerUrl = addressServerUrlTem.toString();
          LOGGER.info("address server url = {}", this.addressServerUrl);
      }
      
      private void initModuleName(NacosClientProperties properties) {
          String moduleNameTmp = properties.getProperty(Constants.CLIENT_MODULE_TYPE);
          if (StringUtils.isNotBlank(moduleNameTmp)) {
              this.moduleName = moduleNameTmp;
          }
      }
      
      @Override
      public void shutdown() throws NacosException {
          if (null != refreshServerListExecutor) {
              refreshServerListExecutor.shutdown();
          }
      }
  }
  