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 */
018package org.apache.hadoop.hbase.chaos.policies;
019
020import java.util.concurrent.ThreadLocalRandom;
021import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
022import org.apache.hadoop.hbase.util.Threads;
023
024/** A policy which does stuff every time interval. */
025public abstract class PeriodicPolicy extends Policy {
026  private long periodMs;
027
028  public PeriodicPolicy(long periodMs) {
029    this.periodMs = periodMs;
030  }
031
032  @Override
033  public void run() {
034    // Add some jitter.
035    int jitter = ThreadLocalRandom.current().nextInt((int) periodMs);
036    LOG.info("Sleeping for {} ms to add jitter", jitter);
037    Threads.sleep(jitter);
038
039    while (!isStopped()) {
040      long start = EnvironmentEdgeManager.currentTime();
041      runOneIteration();
042
043      if (isStopped()) return;
044      long sleepTime = periodMs - (EnvironmentEdgeManager.currentTime() - start);
045      if (sleepTime > 0) {
046        LOG.info("Sleeping for {} ms", sleepTime);
047        Threads.sleep(sleepTime);
048      }
049    }
050  }
051
052  protected abstract void runOneIteration();
053
054  @Override
055  public void init(PolicyContext context) throws Exception {
056    super.init(context);
057    LOG.info("Using ChaosMonkey Policy {}, period={} ms", this.getClass(), periodMs);
058  }
059}