/**
* 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.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.hadoop.util.StringUtils;
/**
* A servlet that is run by the TaskTrackers to provide the task logs via http.
*/
public class TaskLogServlet extends HttpServlet {
private static final long serialVersionUID = -6615764817774487321L;
private boolean haveTaskLog(TaskAttemptID taskId, TaskLog.LogName type) {
File f = TaskLog.getTaskLogFile(taskId, type);
return f.canRead();
}
/**
* Construct the taskLogUrl
* @param taskTrackerHostName
* @param httpPort
* @param taskAttemptID
* @return the taskLogUrl
*/
public static String getTaskLogUrl(String taskTrackerHostName,
String httpPort, String taskAttemptID) {
return ("http://" + taskTrackerHostName + ":" + httpPort
+ "/tasklog?taskid=" + taskAttemptID);
}
/**
* Find the next quotable character in the given array.
* @param data the bytes to look in
* @param offset the first index to look in
* @param end the index after the last one to look in
* @return the index of the quotable character or end if none was found
*/
private static int findFirstQuotable(byte[] data, int offset, int end) {
while (offset < end) {
switch (data[offset]) {
case '<':
case '>':
case '&':
return offset;
default:
offset += 1;
}
}
return offset;
}
private static void quotedWrite(OutputStream out, byte[] data, int offset,
int length) throws IOException {
int end = offset + length;
while (offset < end) {
int next = findFirstQuotable(data, offset, end);
out.write(data, offset, next - offset);
offset = next;
if (offset < end) {
switch (data[offset]) {
case '<':
out.write("<".getBytes());
break;
case '>':
out.write(">".getBytes());
break;
case '&':
out.write("&".getBytes());
break;
default:
out.write(data[offset]);
break;
}
offset += 1;
}
}
}
private void printTaskLog(HttpServletResponse response,
OutputStream out, TaskAttemptID taskId,
long start, long end, boolean plainText,
TaskLog.LogName filter, boolean isCleanup)
throws IOException {
if (!plainText) {
out.write(("<br><b><u>" + filter + " logs</u></b><br>\n" +
"<pre>\n").getBytes());
}
try {
InputStream taskLogReader =
new TaskLog.Reader(taskId, filter, start, end, isCleanup);
byte[] b = new byte[65536];
int result;
while (true) {
result = taskLogReader.read(b);
if (result > 0) {
if (plainText) {
out.write(b, 0, result);
} else {
quotedWrite(out, b, 0, result);
}
} else {
break;
}
}
taskLogReader.close();
if( !plainText ) {
out.write("</pre></td></tr></table><hr><br>\n".getBytes());
}
} catch (IOException ioe) {
if (filter == TaskLog.LogName.DEBUGOUT) {
if (!plainText) {
out.write("</pre><hr><br>\n".getBytes());
}
// do nothing
}
else {
response.sendError(HttpServletResponse.SC_GONE,
"Failed to retrieve " + filter + " log for task: " +
taskId);
out.write(("TaskLogServlet exception:\n" +
StringUtils.stringifyException(ioe) + "\n").getBytes());
}
}
}
/**
* Get the logs via http.
*/
@Override
public void doGet(HttpServletRequest request,
HttpServletResponse response
) throws ServletException, IOException {
long start = 0;
long end = -1;
boolean plainText = false;
TaskLog.LogName filter = null;
boolean isCleanup = false;
String taskIdStr = request.getParameter("taskid");
if (taskIdStr == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST,
"Argument taskid is required");
return;
}
TaskAttemptID taskId = TaskAttemptID.forName(taskIdStr);
String logFilter = request.getParameter("filter");
if (logFilter != null) {
try {
filter = TaskLog.LogName.valueOf(TaskLog.LogName.class,
logFilter.toUpperCase());
} catch (IllegalArgumentException iae) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST,
"Illegal value for filter: " + logFilter);
return;
}
}
String sLogOff = request.getParameter("start");
if (sLogOff != null) {
start = Long.valueOf(sLogOff).longValue();
}
String sLogEnd = request.getParameter("end");
if (sLogEnd != null) {
end = Long.valueOf(sLogEnd).longValue();
}
String sPlainText = request.getParameter("plaintext");
if (sPlainText != null) {
plainText = Boolean.valueOf(sPlainText);
}
String sCleanup = request.getParameter("cleanup");
if (sCleanup != null) {
isCleanup = Boolean.valueOf(sCleanup);
}
OutputStream out = response.getOutputStream();
if( !plainText ) {
out.write(("<html>\n" +
"<title>Task Logs: '" + taskId + "'</title>\n" +
"<body>\n" +
"<h1>Task Logs: '" + taskId + "'</h1><br>\n").getBytes());
if (filter == null) {
printTaskLog(response, out, taskId, start, end, plainText,
TaskLog.LogName.STDOUT, isCleanup);
printTaskLog(response, out, taskId, start, end, plainText,
TaskLog.LogName.STDERR, isCleanup);
printTaskLog(response, out, taskId, start, end, plainText,
TaskLog.LogName.SYSLOG, isCleanup);
if (haveTaskLog(taskId, TaskLog.LogName.DEBUGOUT)) {
printTaskLog(response, out, taskId, start, end, plainText,
TaskLog.LogName.DEBUGOUT, isCleanup);
}
if (haveTaskLog(taskId, TaskLog.LogName.PROFILE)) {
printTaskLog(response, out, taskId, start, end, plainText,
TaskLog.LogName.PROFILE, isCleanup);
}
} else {
printTaskLog(response, out, taskId, start, end, plainText, filter,
isCleanup);
}
out.write("</body></html>\n".getBytes());
out.close();
} else if (filter == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST,
"You must supply a value for `filter' (STDOUT, STDERR, or SYSLOG) if you set plainText = true");
} else {
printTaskLog(response, out, taskId, start, end, plainText, filter,
isCleanup);
}
}
}