/**
* 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 java.io.*;
import java.net.*;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.List;
import java.lang.Math;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.http.HttpConfig;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.hadoop.util.Time;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.server.common.StorageErrorReporter;
import org.apache.hadoop.hdfs.server.common.Storage;
import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
import org.apache.hadoop.hdfs.server.namenode.NNStorage.NameNodeDirType;
import org.apache.hadoop.hdfs.server.protocol.RemoteEditLog;
import org.apache.hadoop.hdfs.util.DataTransferThrottler;
import org.apache.hadoop.io.MD5Hash;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Lists;
/**
* This class provides fetching a specified file from the NameNode.
*/
@InterfaceAudience.Private
public class TransferFsImage {
public final static String CONTENT_LENGTH = "Content-Length";
public final static String MD5_HEADER = "X-MD5-Digest";
@VisibleForTesting
static int timeout = 0;
private static final Log LOG = LogFactory.getLog(TransferFsImage.class);
public static void downloadMostRecentImageToDirectory(String fsName,
File dir) throws IOException {
String fileId = GetImageServlet.getParamStringForMostRecentImage();
getFileClient(fsName, fileId, Lists.newArrayList(dir),
null, false);
}
public static MD5Hash downloadImageToStorage(
String fsName, long imageTxId, Storage dstStorage, boolean needDigest)
throws IOException {
String fileid = GetImageServlet.getParamStringForImage(
imageTxId, dstStorage);
String fileName = NNStorage.getCheckpointImageFileName(imageTxId);
List<File> dstFiles = dstStorage.getFiles(
NameNodeDirType.IMAGE, fileName);
if (dstFiles.isEmpty()) {
throw new IOException("No targets in destination storage!");
}
MD5Hash hash = getFileClient(fsName, fileid, dstFiles, dstStorage, needDigest);
LOG.info("Downloaded file " + dstFiles.get(0).getName() + " size " +
dstFiles.get(0).length() + " bytes.");
return hash;
}
static void downloadEditsToStorage(String fsName, RemoteEditLog log,
NNStorage dstStorage) throws IOException {
assert log.getStartTxId() > 0 && log.getEndTxId() > 0 :
"bad log: " + log;
String fileid = GetImageServlet.getParamStringForLog(
log, dstStorage);
String finalFileName = NNStorage.getFinalizedEditsFileName(
log.getStartTxId(), log.getEndTxId());
List<File> finalFiles = dstStorage.getFiles(NameNodeDirType.EDITS,
finalFileName);
assert !finalFiles.isEmpty() : "No checkpoint targets.";
for (File f : finalFiles) {
if (f.exists() && FileUtil.canRead(f)) {
LOG.info("Skipping download of remote edit log " +
log + " since it already is stored locally at " + f);
return;
} else if (LOG.isDebugEnabled()) {
LOG.debug("Dest file: " + f);
}
}
final long milliTime = System.currentTimeMillis();
String tmpFileName = NNStorage.getTemporaryEditsFileName(
log.getStartTxId(), log.getEndTxId(), milliTime);
List<File> tmpFiles = dstStorage.getFiles(NameNodeDirType.EDITS,
tmpFileName);
getFileClient(fsName, fileid, tmpFiles, dstStorage, false);
LOG.info("Downloaded file " + tmpFiles.get(0).getName() + " size " +
finalFiles.get(0).length() + " bytes.");
CheckpointFaultInjector.getInstance().beforeEditsRename();
for (StorageDirectory sd : dstStorage.dirIterable(NameNodeDirType.EDITS)) {
File tmpFile = NNStorage.getTemporaryEditsFile(sd,
log.getStartTxId(), log.getEndTxId(), milliTime);
File finalizedFile = NNStorage.getFinalizedEditsFile(sd,
log.getStartTxId(), log.getEndTxId());
if (LOG.isDebugEnabled()) {
LOG.debug("Renaming " + tmpFile + " to " + finalizedFile);
}
boolean success = tmpFile.renameTo(finalizedFile);
if (!success) {
LOG.warn("Unable to rename edits file from " + tmpFile
+ " to " + finalizedFile);
}
}
}
/**
* Requests that the NameNode download an image from this node.
*
* @param fsName the http address for the remote NN
* @param imageListenAddress the host/port where the local node is running an
* HTTPServer hosting GetImageServlet
* @param storage the storage directory to transfer the image from
* @param txid the transaction ID of the image to be uploaded
*/
public static void uploadImageFromStorage(String fsName,
InetSocketAddress imageListenAddress,
Storage storage, long txid) throws IOException {
String fileid = GetImageServlet.getParamStringToPutImage(
txid, imageListenAddress, storage);
// this doesn't directly upload an image, but rather asks the NN
// to connect back to the 2NN to download the specified image.
try {
TransferFsImage.getFileClient(fsName, fileid, null, null, false);
} catch (HttpGetFailedException e) {
if (e.getResponseCode() == HttpServletResponse.SC_CONFLICT) {
// this is OK - this means that a previous attempt to upload
// this checkpoint succeeded even though we thought it failed.
LOG.info("Image upload with txid " + txid +
" conflicted with a previous image upload to the " +
"same NameNode. Continuing...", e);
return;
} else {
throw e;
}
}
LOG.info("Uploaded image with txid " + txid + " to namenode at " +
fsName);
}
/**
* A server-side method to respond to a getfile http request
* Copies the contents of the local file into the output stream.
*/
public static void getFileServer(ServletResponse response, File localfile,
FileInputStream infile,
DataTransferThrottler throttler)
throws IOException {
byte buf[] = new byte[HdfsConstants.IO_FILE_BUFFER_SIZE];
ServletOutputStream out = null;
try {
CheckpointFaultInjector.getInstance()
.aboutToSendFile(localfile);
out = response.getOutputStream();
if (CheckpointFaultInjector.getInstance().
shouldSendShortFile(localfile)) {
// Test sending image shorter than localfile
long len = localfile.length();
buf = new byte[(int)Math.min(len/2, HdfsConstants.IO_FILE_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) {
num = infile.read(buf);
if (num <= 0) {
break;
}
if (CheckpointFaultInjector.getInstance()
.shouldCorruptAByte(localfile)) {
// Simulate a corrupted byte on the wire
LOG.warn("SIMULATING A CORRUPT BYTE IN IMAGE TRANSFER!");
buf[0]++;
}
out.write(buf, 0, num);
if (throttler != null) {
throttler.throttle(num);
}
}
} finally {
if (out != null) {
out.close();
}
}
}
/**
* Client-side Method to fetch file from a server
* Copies the response from the URL to a list of local files.
* @param dstStorage if an error occurs writing to one of the files,
* this storage object will be notified.
* @Return a digest of the received file if getChecksum is true
*/
static MD5Hash getFileClient(String nnHostPort,
String queryString, List<File> localPaths,
Storage dstStorage, boolean getChecksum) throws IOException {
String str = HttpConfig.getSchemePrefix() + nnHostPort + "/getimage?" +
queryString;
LOG.info("Opening connection to " + str);
//
// open connection to remote server
//
URL url = new URL(str);
return doGetUrl(url, localPaths, dstStorage, getChecksum);
}
public static MD5Hash doGetUrl(URL url, List<File> localPaths,
Storage dstStorage, boolean getChecksum) throws IOException {
long startTime = Time.monotonicNow();
HttpURLConnection connection = (HttpURLConnection)
SecurityUtil.openSecureHttpConnection(url);
if (timeout <= 0) {
Configuration conf = new HdfsConfiguration();
timeout = conf.getInt(DFSConfigKeys.DFS_IMAGE_TRANSFER_TIMEOUT_KEY,
DFSConfigKeys.DFS_IMAGE_TRANSFER_TIMEOUT_DEFAULT);
}
if (timeout > 0) {
connection.setConnectTimeout(timeout);
connection.setReadTimeout(timeout);
}
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
throw new HttpGetFailedException(
"Image transfer servlet at " + url +
" failed with status code " + connection.getResponseCode() +
"\nResponse message:\n" + connection.getResponseMessage(),
connection);
}
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 " + url);
}
if (localPaths != null) {
String fsImageName = connection.getHeaderField(
GetImageServlet.HADOOP_IMAGE_EDITS_HEADER);
// If the local paths refer to directories, use the server-provided header
// as the filename within that directory
List<File> newLocalPaths = new ArrayList<File>();
for (File localPath : localPaths) {
if (localPath.isDirectory()) {
if (fsImageName == null) {
throw new IOException("No filename header provided by server");
}
newLocalPaths.add(new File(localPath, fsImageName));
} else {
newLocalPaths.add(localPath);
}
}
localPaths = newLocalPaths;
}
MD5Hash advertisedDigest = parseMD5Header(connection);
long received = 0;
InputStream stream = connection.getInputStream();
MessageDigest digester = null;
if (getChecksum) {
digester = MD5Hash.getDigester();
stream = new DigestInputStream(stream, digester);
}
boolean finishedReceiving = false;
List<FileOutputStream> outputStreams = Lists.newArrayList();
try {
if (localPaths != null) {
for (File f : localPaths) {
try {
if (f.exists()) {
LOG.warn("Overwriting existing file " + f
+ " with file downloaded from " + url);
}
outputStreams.add(new FileOutputStream(f));
} catch (IOException ioe) {
LOG.warn("Unable to download file " + f, ioe);
// This will be null if we're downloading the fsimage to a file
// outside of an NNStorage directory.
if (dstStorage != null &&
(dstStorage instanceof StorageErrorReporter)) {
((StorageErrorReporter)dstStorage).reportErrorOnFile(f);
}
}
}
if (outputStreams.isEmpty()) {
throw new IOException(
"Unable to download to any storage directory");
}
}
int num = 1;
byte[] buf = new byte[HdfsConstants.IO_FILE_BUFFER_SIZE];
while (num > 0) {
num = stream.read(buf);
if (num > 0) {
received += num;
for (FileOutputStream fos : outputStreams) {
fos.write(buf, 0, num);
}
}
}
finishedReceiving = true;
} finally {
stream.close();
for (FileOutputStream fos : outputStreams) {
fos.getChannel().force(true);
fos.close();
}
if (finishedReceiving && received != advertisedSize) {
// only throw this exception if we think we read all of it on our end
// -- otherwise a client-side IOException would be masked by this
// exception that makes it look like a server-side problem!
throw new IOException("File " + url + " received length " + received +
" is not of the advertised size " +
advertisedSize);
}
}
double xferSec = Math.max(
((float)(Time.monotonicNow() - startTime)) / 1000.0, 0.001);
long xferKb = received / 1024;
LOG.info(String.format("Transfer took %.2fs at %.2f KB/s",
xferSec, xferKb / xferSec));
if (digester != null) {
MD5Hash computedDigest = new MD5Hash(digester.digest());
if (advertisedDigest != null &&
!computedDigest.equals(advertisedDigest)) {
throw new IOException("File " + url + " computed digest " +
computedDigest + " does not match advertised digest " +
advertisedDigest);
}
return computedDigest;
} else {
return null;
}
}
private static MD5Hash parseMD5Header(HttpURLConnection connection) {
String header = connection.getHeaderField(MD5_HEADER);
return (header != null) ? new MD5Hash(header) : null;
}
public static class HttpGetFailedException extends IOException {
private static final long serialVersionUID = 1L;
private final int responseCode;
HttpGetFailedException(String msg, HttpURLConnection connection) throws IOException {
super(msg);
this.responseCode = connection.getResponseCode();
}
public int getResponseCode() {
return responseCode;
}
}
}