/*
* The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
* (the "License"). You may not use this work except in compliance with the License, which is
* available at www.apache.org/licenses/LICENSE-2.0
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied, as more fully set forth in the License.
*
* See the NOTICE file distributed with this work for information regarding copyright ownership.
*/
package alluxio.web;
import alluxio.Configuration;
import alluxio.Constants;
import alluxio.PropertyKey;
import java.io.File;
import java.io.FileInputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.annotation.concurrent.ThreadSafe;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet that provides data for browsing log files.
*/
@ThreadSafe
public final class WebInterfaceBrowseLogsServlet extends HttpServlet {
private static final long serialVersionUID = 6589358568781503724L;
private final String mBrowseJsp;
private final String mViewJsp;
private static final FilenameFilter LOG_FILE_FILTER = new FilenameFilter() {
@Override
public boolean accept(File dir, String name) {
return name.toLowerCase().endsWith(".log");
}
};
/**
* Creates a new instance of {@link WebInterfaceBrowseLogsServlet}.
*
* @param isMasterServlet whether this is a master servlet
*/
public WebInterfaceBrowseLogsServlet(boolean isMasterServlet) {
String prefix = isMasterServlet ? "/" : "/worker/";
mBrowseJsp = prefix + "browse.jsp";
mViewJsp = prefix + "viewFile.jsp";
}
/**
* This function displays 5KB of a file from a specific offset if it is in ASCII format.
*
* @param file the local file to display
* @param request the {@link HttpServletRequest} object
* @param offset where the file starts to display
*/
private void displayLocalFile(File file, HttpServletRequest request, long offset)
throws IOException {
String fileData;
try (InputStream is = new FileInputStream(file)) {
long fileSize = file.length();
int len = (int) Math.min(5 * Constants.KB, fileSize - offset);
byte[] data = new byte[len];
long skipped = is.skip(offset);
if (skipped < 0) {
// Nothing was skipped.
fileData = "Unable to traverse to offset; is file empty?";
} else if (skipped < offset) {
// Couldn't skip all the way to offset.
fileData = "Unable to traverse to offset; is offset larger than the file?";
} else {
// Read may not read up to len, so only convert what was read.
int read = is.read(data, 0, len);
if (read < 0) {
// Stream couldn't read anything, skip went to EOF?
fileData = "Unable to read file";
} else {
fileData = WebUtils.convertByteArrayToStringWithoutEscape(data, 0, read);
}
}
}
request.setAttribute("fileData", fileData);
}
/**
* Populates attribute fields with data from the MasterInfo associated with this servlet. Errors
* will be displayed in an error field. Debugging can be enabled to display additional data. Will
* eventually redirect the request to a jsp.
*
* @param request the {@link HttpServletRequest} object
* @param response the {@link HttpServletResponse} object
* @throws ServletException if the target resource throws this exception
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setAttribute("debug", Configuration.getBoolean(PropertyKey.DEBUG));
request.setAttribute("invalidPathError", "");
request.setAttribute("viewingOffset", 0);
request.setAttribute("downloadLogFile", 1);
request.setAttribute("baseUrl", "./browseLogs");
request.setAttribute("currentPath", "");
request.setAttribute("showPermissions", false);
String logsPath = Configuration.get(PropertyKey.LOGS_DIR);
File logsDir = new File(logsPath);
String requestFile = request.getParameter("path");
if (requestFile == null || requestFile.isEmpty()) {
// List all log files in the log/ directory.
List<UIFileInfo> fileInfos = new ArrayList<>();
File[] logFiles = logsDir.listFiles(LOG_FILE_FILTER);
if (logFiles != null) {
for (File logFile : logFiles) {
String logFileName = logFile.getName();
fileInfos.add(new UIFileInfo(new UIFileInfo.LocalFileInfo(logFileName, logFileName,
logFile.length(), UIFileInfo.LocalFileInfo.EMPTY_CREATION_TIME,
logFile.lastModified(), logFile.isDirectory())));
}
}
Collections.sort(fileInfos, UIFileInfo.PATH_STRING_COMPARE);
request.setAttribute("nTotalFile", fileInfos.size());
// URL can not determine offset and limit, let javascript in jsp determine and redirect.
if (request.getParameter("offset") == null && request.getParameter("limit") == null) {
getServletContext().getRequestDispatcher(mBrowseJsp).forward(request, response);
return;
}
try {
int offset = Integer.parseInt(request.getParameter("offset"));
int limit = Integer.parseInt(request.getParameter("limit"));
List<UIFileInfo> sub = fileInfos.subList(offset, offset + limit);
request.setAttribute("fileInfos", sub);
} catch (NumberFormatException e) {
request.setAttribute("fatalError",
"Error: offset or limit parse error, " + e.getLocalizedMessage());
getServletContext().getRequestDispatcher(mBrowseJsp).forward(request, response);
return;
} catch (IndexOutOfBoundsException e) {
request.setAttribute("fatalError",
"Error: offset or offset + limit is out of bound, " + e.getLocalizedMessage());
getServletContext().getRequestDispatcher(mBrowseJsp).forward(request, response);
return;
} catch (IllegalArgumentException e) {
request.setAttribute("fatalError", e.getLocalizedMessage());
getServletContext().getRequestDispatcher(mBrowseJsp).forward(request, response);
return;
}
getServletContext().getRequestDispatcher(mBrowseJsp).forward(request, response);
} else {
// Request a specific log file.
// Only allow filenames as the path, to avoid arbitrary local path lookups.
requestFile = new File(requestFile).getName();
request.setAttribute("currentPath", requestFile);
File logFile = new File(logsDir, requestFile);
try {
long fileSize = logFile.length();
String offsetParam = request.getParameter("offset");
long relativeOffset = 0;
long offset;
try {
if (offsetParam != null) {
relativeOffset = Long.parseLong(offsetParam);
}
} catch (NumberFormatException e) {
relativeOffset = 0;
}
String endParam = request.getParameter("end");
// If no param "end" presents, the offset is relative to the beginning; otherwise, it is
// relative to the end of the file.
if (endParam == null) {
offset = relativeOffset;
} else {
offset = fileSize - relativeOffset;
}
if (offset < 0) {
offset = 0;
} else if (offset > fileSize) {
offset = fileSize;
}
displayLocalFile(logFile, request, offset);
request.setAttribute("viewingOffset", offset);
getServletContext().getRequestDispatcher(mViewJsp).forward(request, response);
} catch (IOException e) {
request.setAttribute("invalidPathError", "Error: File " + logFile + " is not available "
+ e.getMessage());
getServletContext().getRequestDispatcher(mViewJsp).forward(request, response);
}
}
}
}