/*
    * 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.hadoop.hbase.chaos.actions;
  
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.chaos.monkies.PolicyBasedChaosMonkey;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Restarts a ratio of the running regionservers at the same time
   */
  public class BatchRestartRsAction extends RestartActionBaseAction {
    float ratio; //ratio of regionservers to restart
    private static final Logger LOG = LoggerFactory.getLogger(BatchRestartRsAction.class);
  
    public BatchRestartRsAction(long sleepTime, float ratio) {
      super(sleepTime);
      this.ratio = ratio;
    }
  
    @Override protected Logger getLogger() {
      return LOG;
    }
  
    @Override
    public void perform() throws Exception {
      getLogger().info(String.format("Performing action: Batch restarting %d%% of region servers",
          (int)(ratio * 100)));
      List<ServerName> selectedServers = PolicyBasedChaosMonkey.selectRandomItems(getCurrentServers(),
          ratio);
  
      Set<ServerName> killedServers = new HashSet<ServerName>();
  
      for (ServerName server : selectedServers) {
        // Don't keep killing servers if we're
        // trying to stop the monkey.
        if (context.isStopping()) {
          break;
        }
        getLogger().info("Killing region server:" + server);
        cluster.killRegionServer(server);
        killedServers.add(server);
      }
  
      for (ServerName server : killedServers) {
        cluster.waitForRegionServerToStop(server, PolicyBasedChaosMonkey.TIMEOUT);
      }
  
      getLogger().info("Killed " + killedServers.size() + " region servers. Reported num of rs:"
          + cluster.getClusterStatus().getServersSize());
  
      sleep(sleepTime);
  
      for (ServerName server : killedServers) {
        getLogger().info("Starting region server:" + server.getHostname());
        cluster.startRegionServer(server.getHostname(), server.getPort());
  
      }
      for (ServerName server : killedServers) {
        cluster.waitForRegionServerToStart(server.getHostname(),
            server.getPort(),
            PolicyBasedChaosMonkey.TIMEOUT);
      }
      getLogger().info("Started " + killedServers.size() +" region servers. Reported num of rs:"
          + cluster.getClusterStatus().getServersSize());
    }
  }