/**
* 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.monkies;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.apache.commons.lang.math.RandomUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.IntegrationTestingUtility;
import org.apache.hadoop.hbase.chaos.policies.Policy;
import org.apache.hadoop.hbase.util.Pair;
/**
* Chaos monkey that given multiple policies will run actions against the cluster.
*/
public class PolicyBasedChaosMonkey extends ChaosMonkey {
private static final Log LOG = LogFactory.getLog(PolicyBasedChaosMonkey.class);
private static final long ONE_SEC = 1000;
private static final long FIVE_SEC = 5 * ONE_SEC;
private static final long ONE_MIN = 60 * ONE_SEC;
public static final long TIMEOUT = ONE_MIN;
final IntegrationTestingUtility util;
/**
* Construct a new ChaosMonkey
* @param util the HBaseIntegrationTestingUtility already configured
* @param policies custom policies to use
*/
public PolicyBasedChaosMonkey(IntegrationTestingUtility util, Policy... policies) {
this.util = util;
this.policies = policies;
}
public PolicyBasedChaosMonkey(IntegrationTestingUtility util, Collection<Policy> policies) {
this.util = util;
this.policies = policies.toArray(new Policy[policies.size()]);
}
/** Selects a random item from the given items */
public static <T> T selectRandomItem(T[] items) {
return items[RandomUtils.nextInt(items.length)];
}
/** Selects a random item from the given items with weights*/
public static <T> T selectWeightedRandomItem(List<Pair<T, Integer>> items) {
int totalWeight = 0;
for (Pair<T, Integer> pair : items) {
totalWeight += pair.getSecond();
}
int cutoff = RandomUtils.nextInt(totalWeight);
int cummulative = 0;
T item = null;
//warn: O(n)
for (int i=0; i<items.size(); i++) {
int curWeight = items.get(i).getSecond();
if ( cutoff < cummulative + curWeight) {
item = items.get(i).getFirst();
break;
}
cummulative += curWeight;
}
return item;
}
/** Selects and returns ceil(ratio * items.length) random items from the given array */
public static <T> List<T> selectRandomItems(T[] items, float ratio) {
int remaining = (int)Math.ceil(items.length * ratio);
List<T> selectedItems = new ArrayList<>(remaining);
for (int i=0; i<items.length && remaining > 0; i++) {
if (RandomUtils.nextFloat() < ((float)remaining/(items.length-i))) {
selectedItems.add(items[i]);
remaining--;
}
}
return selectedItems;
}
private Policy[] policies;
private Thread[] monkeyThreads;
@Override
public void start() throws Exception {
monkeyThreads = new Thread[policies.length];
for (int i=0; i<policies.length; i++) {
policies[i].init(new Policy.PolicyContext(this.util));
Thread monkeyThread = new Thread(policies[i], "ChaosMonkeyThread");
monkeyThread.start();
monkeyThreads[i] = monkeyThread;
}
}
@Override
public void stop(String why) {
if (policies == null) {
return;
}
for (Policy policy : policies) {
policy.stop(why);
}
}
@Override
public boolean isStopped() {
return policies[0].isStopped();
}
/**
* Wait for ChaosMonkey to stop.
* @throws InterruptedException
*/
@Override
public void waitForStop() throws InterruptedException {
if (monkeyThreads == null) {
return;
}
for (Thread monkeyThread : monkeyThreads) {
// TODO: bound the wait time per policy
monkeyThread.join();
}
}
@Override
public boolean isDestructive() {
// TODO: we can look at the actions, and decide to do the restore cluster or not based on them.
return true;
}
}