/*
    * 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
    * <p>
   * http://www.apache.org/licenses/LICENSE-2.0
   * <p>
   * 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.hadoop.hbase.chaos.actions;
  
  import java.io.IOException;
  import java.util.LinkedList;
  import java.util.List;
  
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.chaos.monkies.PolicyBasedChaosMonkey;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hdfs.DFSClient;
  import org.apache.hadoop.hdfs.DistributedFileSystem;
  import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
  import org.apache.hadoop.hdfs.protocol.HdfsConstants;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Action that restarts a random datanode.
   */
  public class RestartRandomDataNodeAction extends RestartActionBaseAction {
    private static final Logger LOG = LoggerFactory.getLogger(RestartRandomDataNodeAction.class);
  
    public RestartRandomDataNodeAction(long sleepTime) {
      super(sleepTime);
    }
  
    @Override protected Logger getLogger() {
      return LOG;
    }
  
    @Override
    public void perform() throws Exception {
      getLogger().info("Performing action: Restart random data node");
      ServerName server = PolicyBasedChaosMonkey.selectRandomItem(getDataNodes());
      restartDataNode(server, sleepTime);
    }
  
    public ServerName[] getDataNodes() throws IOException {
      DistributedFileSystem fs = (DistributedFileSystem) FSUtils.getRootDir(getConf())
          .getFileSystem(getConf());
      DFSClient dfsClient = fs.getClient();
      List<ServerName> hosts = new LinkedList<ServerName>();
      for (DatanodeInfo dataNode: dfsClient.datanodeReport(HdfsConstants.DatanodeReportType.LIVE)) {
        hosts.add(ServerName.valueOf(dataNode.getHostName(), -1, -1));
      }
      return hosts.toArray(new ServerName[0]);
    }
  }