content: /*
   * Copyright 1999-2018 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.core.cluster.lookup;
  
  import com.alibaba.nacos.api.exception.NacosException;
  import com.alibaba.nacos.core.cluster.Member;
  import com.alibaba.nacos.core.cluster.MemberUtil;
  import com.alibaba.nacos.sys.env.EnvUtil;
  import com.alibaba.nacos.sys.file.FileChangeEvent;
  import com.alibaba.nacos.sys.file.FileWatcher;
  import com.alibaba.nacos.sys.file.WatchFileCenter;
  import com.alibaba.nacos.core.utils.Loggers;
  import com.alibaba.nacos.common.utils.StringUtils;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  /**
   * Cluster.conf file managed cluster member node addressing pattern.
   *
   * @author <a href="mailto:liaochuntao@live.com">liaochuntao</a>
   */
  public class FileConfigMemberLookup extends AbstractMemberLookup {
      
      private static final String DEFAULT_SEARCH_SEQ = "cluster.conf";
      
      private FileWatcher watcher = new FileWatcher() {
          @Override
          public void onChange(FileChangeEvent event) {
              readClusterConfFromDisk();
          }
          
          @Override
          public boolean interest(String context) {
              return StringUtils.contains(context, DEFAULT_SEARCH_SEQ);
          }
      };
      
      @Override
      public void doStart() throws NacosException {
          readClusterConfFromDisk();
          
          // Use the inotify mechanism to monitor file changes and automatically
          // trigger the reading of cluster.conf
          try {
              WatchFileCenter.registerWatcher(EnvUtil.getConfPath(), watcher);
          } catch (Throwable e) {
              Loggers.CLUSTER.error("An exception occurred in the launch file monitor : {}", e.getMessage());
          }
      }
      
      @Override
      public boolean useAddressServer() {
          return false;
      }
      
      @Override
      protected void doDestroy() throws NacosException {
          WatchFileCenter.deregisterWatcher(EnvUtil.getConfPath(), watcher);
      }
      
      private void readClusterConfFromDisk() {
          Collection<Member> tmpMembers = new ArrayList<>();
          try {
              List<String> tmp = EnvUtil.readClusterConf();
              tmpMembers = MemberUtil.readServerConf(tmp);
          } catch (Throwable e) {
              Loggers.CLUSTER
                      .error("nacos-XXXX [serverlist] failed to get serverlist from disk!, error : {}", e.getMessage());
          }
          
          afterLookup(tmpMembers);
      }
  }
  