code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.skywalking.oap.server.configuration.nacos;
  
  import com.alibaba.nacos.api.exception.NacosException;
  import com.google.common.base.Strings;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.skywalking.oap.server.configuration.api.AbstractConfigurationProvider;
  import org.apache.skywalking.oap.server.configuration.api.ConfigWatcherRegister;
  import org.apache.skywalking.oap.server.library.module.ModuleStartException;
  import org.apache.skywalking.oap.server.library.util.StringUtil;
  
  /**
   * Get configuration from Nacos.
   */
  @Slf4j
  public class NacosConfigurationProvider extends AbstractConfigurationProvider {
      private NacosServerSettings settings;
  
      @Override
      public String name() {
          return "nacos";
      }
  
      @Override
      public ConfigCreator newConfigCreator() {
          return new ConfigCreator<NacosServerSettings>() {
              @Override
              public Class type() {
                  return NacosServerSettings.class;
              }
  
              @Override
              public void onInitialized(final NacosServerSettings initialized) {
                  settings = initialized;
              }
          };
      }
  
      @Override
      protected ConfigWatcherRegister initConfigReader() throws ModuleStartException {
          log.info("settings: {}", settings);
          if (Strings.isNullOrEmpty(settings.getServerAddr())) {
              throw new ModuleStartException("Nacos serverAddr cannot be null or empty.");
          }
          if (settings.getPort() <= 0) {
              throw new ModuleStartException("Nacos port must be positive integer.");
          }
          if (Strings.isNullOrEmpty(settings.getGroup())) {
              throw new ModuleStartException("Nacos group cannot be null or empty.");
          }
          if (StringUtil.isNotEmpty(settings.getUsername()) && StringUtil.isNotEmpty(settings.getAccessKey())) {
              throw new ModuleStartException("Nacos Auth method should choose either username or accessKey, not both");
          }
          try {
              return new NacosConfigWatcherRegister(settings);
          } catch (NacosException e) {
              throw new ModuleStartException(e.getMessage(), e);
          }
      }
  }
  