/*

  * 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.giraph.utils;

 import org.apache.giraph.conf.DefaultImmutableClassesGiraphConfigurable;

 import org.apache.giraph.conf.GiraphConstants;

 import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration;

 import org.apache.giraph.master.MasterObserver;

 import org.apache.giraph.metrics.AggregatedMetrics;

 import org.apache.giraph.partition.PartitionStats;

 import org.apache.giraph.worker.WorkerObserver;

 import org.apache.log4j.Logger;

 import java.util.List;

 /**

  * An observer for both worker and master that periodically checks if available

  * memory on heap is below certain threshold, and if found to be the case

  * dumps jmap -histo for the process

  */

 public class ReactiveJMapHistoDumper extends

   DefaultImmutableClassesGiraphConfigurable implements

   MasterObserver, WorkerObserver {

   /** Logger */

   private static final Logger LOG = Logger.getLogger(

       ReactiveJMapHistoDumper.class);

   /** Size of mb */

   private static final int MB = 1024 * 1024;

   /** How many msec to sleep between calls */

   private int sleepMillis;

   /** How many lines of output to print */

   private int linesToPrint;

   /** How much free memory is expected */

   private int minFreeMemory;

   /** The jmap printing thread */

   private Thread thread;

   /** Halt jmap thread */

   private volatile boolean stop = false;

   /** Path to jmap*/

   private String jmapPath;

   @Override

   public void preLoad() {

     // This is called by both WorkerObserver and MasterObserver

     startSupervisorThread();

   }

   @Override

   public void postSave() {

     // This is called by both WorkerObserver and MasterObserver

     joinSupervisorThread();

   }

   @Override

   public void preApplication() {

   }

   @Override

   public void postApplication() {

   }

   /**

    * Join the supervisor thread

    */

   private void joinSupervisorThread() {

     stop = true;

     try {

       thread.join(sleepMillis + 5000);

     } catch (InterruptedException e) {

       LOG.error("Failed to join jmap thread");

     }

   }

   /**

    * Start the supervisor thread

    */

   public void startSupervisorThread() {

     stop = false;

     final Runtime runtime = Runtime.getRuntime();

     thread = ThreadUtils.startThread(new Runnable() {

       @Override

       public void run() {

         while (!stop) {

           long potentialMemory = (runtime.maxMemory() -

               runtime.totalMemory()) + runtime.freeMemory();

           if (potentialMemory / MB < minFreeMemory) {

             JMap.heapHistogramDump(linesToPrint, jmapPath);

           }

           ThreadUtils.trySleep(sleepMillis);

         }

       }

     }, "ReactiveJMapHistoDumperSupervisorThread");

   }

   @Override

   public void preSuperstep(long superstep) { }

   @Override

   public void postSuperstep(long superstep) { }

   @Override

   public void superstepMetricsUpdate(long superstep,

       AggregatedMetrics aggregatedMetrics,

       List<PartitionStats> partitionStatsList) { }

   @Override

   public void applicationFailed(Exception e) { }

   @Override

   public void setConf(ImmutableClassesGiraphConfiguration configuration) {

     sleepMillis = GiraphConstants.JMAP_SLEEP_MILLIS.get(configuration);

     linesToPrint = GiraphConstants.JMAP_PRINT_LINES.get(configuration);

     minFreeMemory = GiraphConstants.MIN_FREE_MBS_ON_HEAP.get(configuration);

     jmapPath = GiraphConstants.JMAP_PATH.get(configuration);

   }

 }