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 */ 018 019 package org.apache.hadoop.yarn; 020 021 import java.io.File; 022 import java.io.Flushable; 023 import java.util.LinkedList; 024 import java.util.Queue; 025 026 import org.apache.hadoop.classification.InterfaceAudience.Public; 027 import org.apache.hadoop.classification.InterfaceStability.Unstable; 028 import org.apache.log4j.FileAppender; 029 import org.apache.log4j.spi.LoggingEvent; 030 031 /** 032 * A simple log4j-appender for container's logs. 033 * 034 */ 035 @Public 036 @Unstable 037 public class ContainerLogAppender extends FileAppender 038 implements Flushable 039 { 040 private String containerLogDir; 041 //so that log4j can configure it from the configuration(log4j.properties). 042 private int maxEvents; 043 private Queue<LoggingEvent> tail = null; 044 045 @Override 046 public void activateOptions() { 047 synchronized (this) { 048 if (maxEvents > 0) { 049 tail = new LinkedList<LoggingEvent>(); 050 } 051 setFile(new File(this.containerLogDir, "syslog").toString()); 052 setAppend(true); 053 super.activateOptions(); 054 } 055 } 056 057 @Override 058 public void append(LoggingEvent event) { 059 synchronized (this) { 060 if (tail == null) { 061 super.append(event); 062 } else { 063 if (tail.size() >= maxEvents) { 064 tail.remove(); 065 } 066 tail.add(event); 067 } 068 } 069 } 070 071 @Override 072 public void flush() { 073 if (qw != null) { 074 qw.flush(); 075 } 076 } 077 078 @Override 079 public synchronized void close() { 080 if (tail != null) { 081 for(LoggingEvent event: tail) { 082 super.append(event); 083 } 084 } 085 super.close(); 086 } 087 088 /** 089 * Getter/Setter methods for log4j. 090 */ 091 092 public String getContainerLogDir() { 093 return this.containerLogDir; 094 } 095 096 public void setContainerLogDir(String containerLogDir) { 097 this.containerLogDir = containerLogDir; 098 } 099 100 private static final int EVENT_SIZE = 100; 101 102 public long getTotalLogFileSize() { 103 return maxEvents * EVENT_SIZE; 104 } 105 106 public void setTotalLogFileSize(long logSize) { 107 maxEvents = (int) logSize / EVENT_SIZE; 108 } 109 }