001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.hbase.chaos.policies;
020
021import java.util.ArrayList;
022import java.util.Arrays;
023import java.util.List;
024
025import org.apache.hadoop.hbase.chaos.actions.Action;
026import org.apache.hadoop.hbase.chaos.monkies.PolicyBasedChaosMonkey;
027import org.apache.hadoop.hbase.util.Pair;
028import org.apache.hadoop.util.StringUtils;
029
030/**
031 * A policy, which picks a random action according to the given weights,
032 * and performs it every configurable period.
033 */
034public class PeriodicRandomActionPolicy extends PeriodicPolicy {
035  private List<Pair<Action, Integer>> actions;
036
037  public PeriodicRandomActionPolicy(long periodMs, List<Pair<Action, Integer>> actions) {
038    super(periodMs);
039    this.actions = actions;
040  }
041
042  public PeriodicRandomActionPolicy(long periodMs, Pair<Action, Integer>... actions) {
043    // We don't expect it to be modified.
044    this(periodMs, Arrays.asList(actions));
045  }
046
047  public PeriodicRandomActionPolicy(long periodMs, Action... actions) {
048    super(periodMs);
049    this.actions = new ArrayList<>(actions.length);
050    for (Action action : actions) {
051      this.actions.add(new Pair<>(action, 1));
052    }
053  }
054
055  @Override
056  protected void runOneIteration() {
057    Action action = PolicyBasedChaosMonkey.selectWeightedRandomItem(actions);
058    try {
059      action.perform();
060    } catch (Exception ex) {
061      LOG.warn("Exception performing action: " + StringUtils.stringifyException(ex));
062    }
063  }
064
065  @Override
066  public void init(PolicyContext context) throws Exception {
067    super.init(context);
068    for (Pair<Action, Integer> action : actions) {
069      action.getFirst().init(this.context);
070    }
071  }
072}