/**
* 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.hdfs.server.namenode;
import org.apache.commons.logging.*;
import java.io.*;
import java.net.*;
import java.security.DigestInputStream;
import java.security.DigestOutputStream;
import java.security.MessageDigest;
import java.util.Iterator;
import java.util.Map;
import java.lang.Math;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletRequest;
import org.apache.hadoop.hdfs.protocol.FSConstants;
import org.apache.hadoop.hdfs.util.DataTransferThrottler;
import org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode.ErrorSimulator;
import org.apache.hadoop.io.MD5Hash;
/**
* This class provides fetching a specified file from the NameNode.
*/
class TransferFsImage implements FSConstants {
public final static String CONTENT_LENGTH = "Content-Length";
public static final Log LOG = LogFactory.getLog(TransferFsImage.class.getName());
private boolean isGetImage;
private boolean isGetEdit;
private boolean isGetEditNew;
private boolean isPutImage;
private int remoteport;
private String machineName;
private CheckpointSignature token;
/**
* File downloader.
* @param pmap key=value[] map that is passed to the http servlet as
* url parameters
* @param request the object from which this servelet reads the url contents
* @param response the object into which this servelet writes the url contents
* @throws IOException
*/
public TransferFsImage(Map<String,String[]> pmap,
HttpServletRequest request,
HttpServletResponse response
) throws IOException {
isGetImage = isGetEdit = isPutImage = false;
remoteport = 0;
machineName = null;
token = null;
for (Iterator<String> it = pmap.keySet().iterator(); it.hasNext();) {
String key = it.next();
if (key.equals("getimage")) {
isGetImage = true;
} else if (key.equals("getedit")) {
isGetEdit = true;
} else if (key.equals("geteditnew")) {
isGetEditNew = true;
} else if (key.equals("putimage")) {
isPutImage = true;
} else if (key.equals("port")) {
remoteport = new Integer(pmap.get("port")[0]).intValue();
} else if (key.equals("machine")) {
machineName = pmap.get("machine")[0];
} else if (key.equals("token")) {
token = new CheckpointSignature(pmap.get("token")[0]);
}
}
int numGets = (isGetImage?1:0) + (isGetEdit?1:0) + (isGetEditNew?1:0);
if ((numGets > 1) || (numGets == 0) && !isPutImage) {
throw new IOException("Illegal parameters to TransferFsImage");
}
}
boolean getEdit() {
return isGetEdit;
}
boolean getEditNew() {
return isGetEditNew;
}
boolean getImage() {
return isGetImage;
}
boolean putImage() {
return isPutImage;
}
CheckpointSignature getToken() {
return token;
}
String getInfoServer() throws IOException{
if (machineName == null || remoteport == 0) {
throw new IOException ("MachineName and port undefined");
}
return machineName + ":" + remoteport;
}
/**
* A server-side method to respond to a getfile http request
* Copies the contents of the local file into the output stream.
*/
static void getFileServer(OutputStream outstream, File localfile, DataTransferThrottler throttler)
throws IOException {
byte buf[] = new byte[BUFFER_SIZE];
FileInputStream infile = null;
long totalReads = 0, totalSends = 0;
try {
infile = new FileInputStream(localfile);
if (ErrorSimulator.getErrorSimulation(2)
&& localfile.getAbsolutePath().contains("secondary")) {
// throw exception only when the secondary sends its image
throw new IOException("If this exception is not caught by the " +
"name-node fs image will be truncated.");
}
if (ErrorSimulator.getErrorSimulation(3)
&& localfile.getAbsolutePath().contains("fsimage")) {
// Test sending image shorter than localfile
long len = localfile.length();
buf = new byte[(int)Math.min(len/2, BUFFER_SIZE)];
// This will read at most half of the image
// and the rest of the image will be sent over the wire
infile.read(buf);
}
int num = 1;
while (num > 0) {
long startRead = System.currentTimeMillis();
num = infile.read(buf);
if (num <= 0) {
break;
}
outstream.write(buf, 0, num);
if (throttler != null) {
throttler.throttle(num);
}
}
} finally {
if (infile != null) {
infile.close();
}
}
}
/**
* Client-side Method to fetch file from a server
* Copies the response from the URL to a list of local files.
*
* @Return a digest of the received file if getChecksum is true
*/
static MD5Hash getFileClient(String fsName, String id, File[] localPath,
boolean getChecksum)
throws IOException {
byte[] buf = new byte[BUFFER_SIZE];
StringBuffer str = new StringBuffer("http://"+fsName+"/getimage?");
str.append(id);
//
// open connection to remote server
//
URL url = new URL(str.toString());
URLConnection connection = url.openConnection();
if (localPath == null) {
// Putting the image back
connection.setReadTimeout(2 * 60 * 60 * 1000); // 2 hours to upload
} else {
connection.setReadTimeout(10 * 60 * 1000); // 10 minute read timeout
}
long advertisedSize;
String contentLength = connection.getHeaderField(CONTENT_LENGTH);
if (contentLength != null) {
advertisedSize = Long.parseLong(contentLength);
} else {
throw new IOException(CONTENT_LENGTH + " header is not provided " +
"by the namenode when trying to fetch " + str);
}
long received = 0;
InputStream stream = connection.getInputStream();
MessageDigest digester = null;
if (getChecksum) {
digester = MD5Hash.getDigester();
stream = new DigestInputStream(stream, digester);
}
FileOutputStream[] output = null;
try {
if (localPath != null) {
output = new FileOutputStream[localPath.length];
for (int i = 0; i < output.length; i++) {
output[i] = new FileOutputStream(localPath[i]);
}
}
int num = 1;
while (num > 0) {
num = stream.read(buf);
if (num > 0 && localPath != null) {
received += num;
for (int i = 0; i < output.length; i++) {
output[i].write(buf, 0, num);
}
}
}
} finally {
stream.close();
if (output != null) {
for (int i = 0; i < output.length; i++) {
if (output[i] != null) {
output[i].close();
}
}
}
if (received != advertisedSize) {
throw new IOException("File " + str + " received length " + received +
" is not of the advertised size " +
advertisedSize);
}
}
return digester==null ? null : new MD5Hash(digester.digest());
}
}