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.monkies;
020
021import java.util.Arrays;
022import java.util.Collection;
023import java.util.Collections;
024import java.util.List;
025
026import org.apache.commons.lang3.RandomUtils;
027import org.apache.hadoop.hbase.IntegrationTestingUtility;
028import org.apache.hadoop.hbase.chaos.policies.Policy;
029import org.apache.hadoop.hbase.util.Pair;
030import org.slf4j.Logger;
031import org.slf4j.LoggerFactory;
032
033/**
034 * Chaos monkey that given multiple policies will run actions against the cluster.
035 */
036public class PolicyBasedChaosMonkey extends ChaosMonkey {
037
038  private static final Logger LOG = LoggerFactory.getLogger(PolicyBasedChaosMonkey.class);
039  private static final long ONE_SEC = 1000;
040  private static final long FIVE_SEC = 5 * ONE_SEC;
041  private static final long ONE_MIN = 60 * ONE_SEC;
042
043  public static final long TIMEOUT = ONE_MIN;
044
045  final IntegrationTestingUtility util;
046
047  /**
048   * Construct a new ChaosMonkey
049   * @param util the HBaseIntegrationTestingUtility already configured
050   * @param policies custom policies to use
051   */
052  public PolicyBasedChaosMonkey(IntegrationTestingUtility util, Policy... policies) {
053    this.util = util;
054    this.policies = policies;
055  }
056
057  public PolicyBasedChaosMonkey(IntegrationTestingUtility util, Collection<Policy> policies) {
058    this.util = util;
059    this.policies = policies.toArray(new Policy[policies.size()]);
060  }
061
062
063  /** Selects a random item from the given items */
064  public static <T> T selectRandomItem(T[] items) {
065    return items[RandomUtils.nextInt(0, items.length)];
066  }
067
068  /** Selects a random item from the given items with weights*/
069  public static <T> T selectWeightedRandomItem(List<Pair<T, Integer>> items) {
070    int totalWeight = 0;
071    for (Pair<T, Integer> pair : items) {
072      totalWeight += pair.getSecond();
073    }
074
075    int cutoff = RandomUtils.nextInt(0, totalWeight);
076    int cummulative = 0;
077    T item = null;
078
079    //warn: O(n)
080    for (int i=0; i<items.size(); i++) {
081      int curWeight = items.get(i).getSecond();
082      if ( cutoff < cummulative + curWeight) {
083        item = items.get(i).getFirst();
084        break;
085      }
086      cummulative += curWeight;
087    }
088
089    return item;
090  }
091
092  /** Selects and returns ceil(ratio * items.length) random items from the given array */
093  public static <T> List<T> selectRandomItems(T[] items, float ratio) {
094    int selectedNumber = (int)Math.ceil(items.length * ratio);
095
096    List<T> originalItems = Arrays.asList(items);
097    Collections.shuffle(originalItems);
098
099    int startIndex = RandomUtils.nextInt(0, items.length - selectedNumber);
100    return originalItems.subList(startIndex, startIndex + selectedNumber);
101  }
102
103  private Policy[] policies;
104  private Thread[] monkeyThreads;
105
106  @Override
107  public void start() throws Exception {
108    monkeyThreads = new Thread[policies.length];
109
110    for (int i=0; i<policies.length; i++) {
111      policies[i].init(new Policy.PolicyContext(this.util));
112      Thread monkeyThread = new Thread(policies[i], "ChaosMonkey");
113      monkeyThread.start();
114      monkeyThreads[i] = monkeyThread;
115    }
116  }
117
118  @Override
119  public void stop(String why) {
120    if (policies == null) {
121      return;
122    }
123
124    for (Policy policy : policies) {
125      policy.stop(why);
126    }
127  }
128
129  @Override
130  public boolean isStopped() {
131    return policies[0].isStopped();
132  }
133
134  /**
135   * Wait for ChaosMonkey to stop.
136   * @throws InterruptedException
137   */
138  @Override
139  public void waitForStop() throws InterruptedException {
140    if (monkeyThreads == null) {
141      return;
142    }
143    for (Thread monkeyThread : monkeyThreads) {
144      // TODO: bound the wait time per policy
145      monkeyThread.join();
146    }
147  }
148
149  @Override
150  public boolean isDestructive() {
151    // TODO: we can look at the actions, and decide to do the restore cluster or not based on them.
152    return true;
153  }
154}