| /** |
| * 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.yarn.util; |
| |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.classification.InterfaceAudience.Public; |
| import org.apache.hadoop.classification.InterfaceStability.Evolving; |
| import org.apache.hadoop.service.AbstractService; |
| |
| /** |
| * A simple liveliness monitor with which clients can register, trust the |
| * component to monitor liveliness, get a call-back on expiry and then finally |
| * unregister. |
| */ |
| @Public |
| @Evolving |
| public abstract class AbstractLivelinessMonitor<O> extends AbstractService { |
| |
| private static final Log LOG = LogFactory.getLog(AbstractLivelinessMonitor.class); |
| |
| //thread which runs periodically to see the last time since a heartbeat is |
| //received. |
| private Thread checkerThread; |
| private volatile boolean stopped; |
| public static final int DEFAULT_EXPIRE = 5*60*1000;//5 mins |
| private long expireInterval = DEFAULT_EXPIRE; |
| private long monitorInterval = expireInterval / 3; |
| private volatile boolean resetTimerOnStart = true; |
| |
| private final Clock clock; |
| |
| private Map<O, Long> running = new HashMap<O, Long>(); |
| |
| public AbstractLivelinessMonitor(String name, Clock clock) { |
| super(name); |
| this.clock = clock; |
| } |
| |
| public AbstractLivelinessMonitor(String name) { |
| this(name, new MonotonicClock()); |
| } |
| |
| @Override |
| protected void serviceStart() throws Exception { |
| assert !stopped : "starting when already stopped"; |
| resetTimer(); |
| checkerThread = new Thread(new PingChecker()); |
| checkerThread.setName("Ping Checker"); |
| checkerThread.start(); |
| super.serviceStart(); |
| } |
| |
| @Override |
| protected void serviceStop() throws Exception { |
| stopped = true; |
| if (checkerThread != null) { |
| checkerThread.interrupt(); |
| } |
| super.serviceStop(); |
| } |
| |
| protected abstract void expire(O ob); |
| |
| protected void setExpireInterval(int expireInterval) { |
| this.expireInterval = expireInterval; |
| } |
| |
| protected long getExpireInterval(O o) { |
| // by-default return for all the registered object interval. |
| return this.expireInterval; |
| } |
| |
| protected void setMonitorInterval(long monitorInterval) { |
| this.monitorInterval = monitorInterval; |
| } |
| |
| public synchronized void receivedPing(O ob) { |
| //only put for the registered objects |
| if (running.containsKey(ob)) { |
| running.put(ob, clock.getTime()); |
| } |
| } |
| |
| public synchronized void register(O ob) { |
| register(ob, clock.getTime()); |
| } |
| |
| public synchronized void register(O ob, long expireTime) { |
| running.put(ob, expireTime); |
| } |
| |
| public synchronized void unregister(O ob) { |
| running.remove(ob); |
| } |
| |
| public synchronized void resetTimer() { |
| if (resetTimerOnStart) { |
| long time = clock.getTime(); |
| for (O ob : running.keySet()) { |
| running.put(ob, time); |
| } |
| } |
| } |
| |
| protected void setResetTimeOnStart(boolean resetTimeOnStart) { |
| this.resetTimerOnStart = resetTimeOnStart; |
| } |
| |
| private class PingChecker implements Runnable { |
| |
| @Override |
| public void run() { |
| while (!stopped && !Thread.currentThread().isInterrupted()) { |
| synchronized (AbstractLivelinessMonitor.this) { |
| Iterator<Map.Entry<O, Long>> iterator = running.entrySet().iterator(); |
| |
| // avoid calculating current time everytime in loop |
| long currentTime = clock.getTime(); |
| |
| while (iterator.hasNext()) { |
| Map.Entry<O, Long> entry = iterator.next(); |
| O key = entry.getKey(); |
| long interval = getExpireInterval(key); |
| if (currentTime > entry.getValue() + interval) { |
| iterator.remove(); |
| expire(key); |
| LOG.info("Expired:" + entry.getKey().toString() |
| + " Timed out after " + interval / 1000 + " secs"); |
| } |
| } |
| } |
| try { |
| Thread.sleep(monitorInterval); |
| } catch (InterruptedException e) { |
| LOG.info(getName() + " thread interrupted"); |
| break; |
| } |
| } |
| } |
| } |
| |
| } |