- /**
- * 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.mapred;
- import java.util.LinkedList;
- import java.util.Queue;
- import org.apache.log4j.FileAppender;
- import org.apache.log4j.spi.LoggingEvent;
- /**
- * A simple log4j-appender for the task child's
- * map-reduce system logs.
- *
- */
- public class TaskLogAppender extends FileAppender {
- private String taskId; //taskId should be managed as String rather than TaskID object
- //so that log4j can configure it from the configuration(log4j.properties).
- private int maxEvents;
- private Queue<LoggingEvent> tail = null;
- @Override
- public void activateOptions() {
- synchronized (this) {
- if (maxEvents > 0) {
- tail = new LinkedList<LoggingEvent>();
- }
- setFile(TaskLog.getTaskLogFile(TaskAttemptID.forName(taskId),
- TaskLog.LogName.SYSLOG).toString());
- setAppend(true);
- super.activateOptions();
- }
- }
- @Override
- public void append(LoggingEvent event) {
- synchronized (this) {
- if (tail == null) {
- super.append(event);
- } else {
- if (tail.size() >= maxEvents) {
- tail.remove();
- }
- tail.add(event);
- }
- }
- }
- public void flush() {
- qw.flush();
- }
- @Override
- public synchronized void close() {
- if (tail != null) {
- for(LoggingEvent event: tail) {
- super.append(event);
- }
- }
- super.close();
- }
- /**
- * Getter/Setter methods for log4j.
- */
- public String getTaskId() {
- return taskId;
- }
- public void setTaskId(String taskId) {
- this.taskId = taskId;
- }
- private static final int EVENT_SIZE = 100;
- public long getTotalLogFileSize() {
- return maxEvents * EVENT_SIZE;
- }
- public void setTotalLogFileSize(long logSize) {
- maxEvents = (int) logSize / EVENT_SIZE;
- }
- }