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.yarn;
020
021import java.io.File;
022import java.io.Flushable;
023import java.util.LinkedList;
024import java.util.Queue;
025
026import org.apache.hadoop.classification.InterfaceAudience.Public;
027import org.apache.hadoop.classification.InterfaceStability.Unstable;
028import org.apache.log4j.FileAppender;
029import org.apache.log4j.spi.LoggingEvent;
030
031/**
032 * A simple log4j-appender for container's logs.
033 * 
034 */
035@Public
036@Unstable
037public class ContainerLogAppender extends FileAppender
038  implements Flushable
039{
040  private String containerLogDir;
041  private String containerLogFile;
042  //so that log4j can configure it from the configuration(log4j.properties). 
043  private int maxEvents;
044  private Queue<LoggingEvent> tail = null;
045  private boolean closing = false;
046
047  @Override
048  public void activateOptions() {
049    synchronized (this) {
050      if (maxEvents > 0) {
051        tail = new LinkedList<LoggingEvent>();
052      }
053      setFile(new File(this.containerLogDir, containerLogFile).toString());
054      setAppend(true);
055      super.activateOptions();
056    }
057  }
058  
059  @Override
060  public void append(LoggingEvent event) {
061    synchronized (this) {
062      if (closing) { // When closing drop any new/transitive CLA appending
063        return;
064      }
065      if (tail == null) {
066        super.append(event);
067      } else {
068        if (tail.size() >= maxEvents) {
069          tail.remove();
070        }
071        tail.add(event);
072      }
073    }
074  }
075  
076  @Override
077  public void flush() {
078    if (qw != null) {
079      qw.flush();
080    }
081  }
082
083  @Override
084  public synchronized void close() {
085    closing = true;
086    if (tail != null) {
087      for (LoggingEvent event : tail) {
088        super.append(event);
089      }
090    }
091    super.close();
092  }
093
094  /**
095   * Getter/Setter methods for log4j.
096   */
097  
098  public String getContainerLogDir() {
099    return this.containerLogDir;
100  }
101
102  public void setContainerLogDir(String containerLogDir) {
103    this.containerLogDir = containerLogDir;
104  }
105
106  public String getContainerLogFile() {
107    return containerLogFile;
108  }
109
110  public void setContainerLogFile(String containerLogFile) {
111    this.containerLogFile = containerLogFile;
112  }
113
114  private static final int EVENT_SIZE = 100;
115  
116  public long getTotalLogFileSize() {
117    return maxEvents * EVENT_SIZE;
118  }
119
120  public void setTotalLogFileSize(long logSize) {
121    maxEvents = (int) logSize / EVENT_SIZE;
122  }
123}