org.apache.hadoop.hdfs.BlockReaderFactory Maven / Gradle / Ivy
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* 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;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.InetSocketAddress;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.net.Peer;
import org.apache.hadoop.hdfs.protocol.DatanodeID;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.protocol.HdfsProtoUtil;
import org.apache.hadoop.hdfs.protocol.datatransfer.Sender;
import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.BlockOpResponseProto;
import org.apache.hadoop.hdfs.security.token.block.BlockTokenIdentifier;
import org.apache.hadoop.hdfs.security.token.block.InvalidBlockTokenException;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.ipc.RemoteException;
import org.apache.hadoop.net.unix.DomainSocket;
import org.apache.hadoop.security.AccessControlException;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.security.token.SecretManager.InvalidToken;
import org.apache.hadoop.security.token.Token;
/**
* Utility class to create BlockReader implementations.
*/
@InterfaceAudience.Private
public class BlockReaderFactory {
/**
* Create a new BlockReader specifically to satisfy a read.
* This method also sends the OP_READ_BLOCK request.
*
* @param conf the DFSClient configuration
* @param file File location
* @param block The block object
* @param blockToken The block token for security
* @param startOffset The read offset, relative to block head
* @param len The number of bytes to read, or -1 to read as many as
* possible.
* @param bufferSize The IO buffer size (not the client buffer size)
* Ignored except on the legacy BlockReader.
* @param verifyChecksum Whether to verify checksum
* @param clientName Client name. Used for log messages.
* @param peer The peer
* @param datanodeID The datanode that the Peer is connected to
* @param domainSocketFactory The DomainSocketFactory to notify if the Peer
* is a DomainPeer which turns out to be faulty.
* If null, no factory will be notified in this
* case.
* @param allowShortCircuitLocalReads True if short-circuit local reads
* should be allowed.
* @return New BlockReader instance
*/
@SuppressWarnings("deprecation")
public static BlockReader newBlockReader(
Configuration conf,
String file,
ExtendedBlock block,
Token blockToken,
long startOffset, long len,
boolean verifyChecksum,
String clientName,
Peer peer,
DatanodeID datanodeID,
DomainSocketFactory domSockFactory,
PeerCache peerCache,
FileInputStreamCache fisCache,
boolean allowShortCircuitLocalReads)
throws IOException {
peer.setReadTimeout(conf.getInt(DFSConfigKeys.DFS_CLIENT_SOCKET_TIMEOUT_KEY,
HdfsServerConstants.READ_TIMEOUT));
peer.setWriteTimeout(HdfsServerConstants.WRITE_TIMEOUT);
if (peer.getDomainSocket() != null) {
if (allowShortCircuitLocalReads &&
(!conf.getBoolean(DFSConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADERLOCAL,
DFSConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADERLOCAL_DEFAULT))) {
// If this is a domain socket, and short-circuit local reads are
// enabled, try to set up a BlockReaderLocal.
BlockReader reader = newShortCircuitBlockReader(conf, file,
block, blockToken, startOffset, len, peer, datanodeID,
domSockFactory, verifyChecksum, fisCache);
if (reader != null) {
// One we've constructed the short-circuit block reader, we don't
// need the socket any more. So let's return it to the cache.
if (peerCache != null) {
peerCache.put(datanodeID, peer);
} else {
IOUtils.cleanup(null, peer);
}
return reader;
}
}
// If this is a domain socket and we couldn't (or didn't want to) set
// up a BlockReaderLocal, check that we are allowed to pass data traffic
// over the socket before proceeding.
if (!conf.getBoolean(DFSConfigKeys.DFS_CLIENT_DOMAIN_SOCKET_DATA_TRAFFIC,
DFSConfigKeys.DFS_CLIENT_DOMAIN_SOCKET_DATA_TRAFFIC_DEFAULT)) {
throw new IOException("Because we can't do short-circuit access, " +
"and data traffic over domain sockets is disabled, " +
"we cannot use this socket to talk to " + datanodeID);
}
}
if (conf.getBoolean(DFSConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADER,
DFSConfigKeys.DFS_CLIENT_USE_LEGACY_BLOCKREADER_DEFAULT)) {
return RemoteBlockReader.newBlockReader(file,
block, blockToken, startOffset, len,
conf.getInt(DFSConfigKeys.IO_FILE_BUFFER_SIZE_KEY,
DFSConfigKeys.IO_FILE_BUFFER_SIZE_DEFAULT),
verifyChecksum, clientName, peer, datanodeID, peerCache);
} else {
return RemoteBlockReader2.newBlockReader(
file, block, blockToken, startOffset, len,
verifyChecksum, clientName, peer, datanodeID, peerCache);
}
}
/**
* Create a new short-circuit BlockReader.
*
* Here, we ask the DataNode to pass us file descriptors over our
* DomainSocket. If the DataNode declines to do so, we'll return null here;
* otherwise, we'll return the BlockReaderLocal. If the DataNode declines,
* this function will inform the DomainSocketFactory that short-circuit local
* reads are disabled for this DataNode, so that we don't ask again.
*
* @param conf the configuration.
* @param file the file name. Used in log messages.
* @param block The block object.
* @param blockToken The block token for security.
* @param startOffset The read offset, relative to block head.
* @param len The number of bytes to read, or -1 to read
* as many as possible.
* @param peer The peer to use.
* @param datanodeID The datanode that the Peer is connected to.
* @param domSockFactory The DomainSocketFactory to notify if the Peer
* is a DomainPeer which turns out to be faulty.
* If null, no factory will be notified in this
* case.
* @param verifyChecksum True if we should verify the checksums.
* Note: even if this is true, when
* DFS_CLIENT_READ_CHECKSUM_SKIP_CHECKSUM_KEY is
* set, we will skip checksums.
*
* @return The BlockReaderLocal, or null if the
* DataNode declined to provide short-circuit
* access.
* @throws IOException If there was a communication error.
*/
private static BlockReaderLocal newShortCircuitBlockReader(
Configuration conf, String file, ExtendedBlock block,
Token blockToken, long startOffset,
long len, Peer peer, DatanodeID datanodeID,
DomainSocketFactory domSockFactory, boolean verifyChecksum,
FileInputStreamCache fisCache) throws IOException {
final DataOutputStream out =
new DataOutputStream(new BufferedOutputStream(
peer.getOutputStream()));
new Sender(out).requestShortCircuitFds(block, blockToken, 1);
DataInputStream in =
new DataInputStream(peer.getInputStream());
BlockOpResponseProto resp = BlockOpResponseProto.parseFrom(
HdfsProtoUtil.vintPrefixed(in));
DomainSocket sock = peer.getDomainSocket();
switch (resp.getStatus()) {
case SUCCESS:
BlockReaderLocal reader = null;
byte buf[] = new byte[1];
FileInputStream fis[] = new FileInputStream[2];
sock.recvFileInputStreams(fis, buf, 0, buf.length);
try {
reader = new BlockReaderLocal(conf, file, block,
startOffset, len, fis[0], fis[1], datanodeID, verifyChecksum,
fisCache);
} finally {
if (reader == null) {
IOUtils.cleanup(DFSClient.LOG, fis[0], fis[1]);
}
}
return reader;
case ERROR_UNSUPPORTED:
if (!resp.hasShortCircuitAccessVersion()) {
DFSClient.LOG.warn("short-circuit read access is disabled for " +
"DataNode " + datanodeID + ". reason: " + resp.getMessage());
domSockFactory.disableShortCircuitForPath(sock.getPath());
} else {
DFSClient.LOG.warn("short-circuit read access for the file " +
file + " is disabled for DataNode " + datanodeID +
". reason: " + resp.getMessage());
}
return null;
case ERROR_ACCESS_TOKEN:
String msg = "access control error while " +
"attempting to set up short-circuit access to " +
file + resp.getMessage();
DFSClient.LOG.debug(msg);
throw new InvalidBlockTokenException(msg);
default:
DFSClient.LOG.warn("error while attempting to set up short-circuit " +
"access to " + file + ": " + resp.getMessage());
domSockFactory.disableShortCircuitForPath(sock.getPath());
return null;
}
}
/**
* File name to print when accessing a block directly (from servlets)
* @param s Address of the block location
* @param poolId Block pool ID of the block
* @param blockId Block ID of the block
* @return string that has a file name for debug purposes
*/
public static String getFileName(final InetSocketAddress s,
final String poolId, final long blockId) {
return s.toString() + ":" + poolId + ":" + blockId;
}
/**
* Get {@link BlockReaderLocalLegacy} for short circuited local reads.
* This block reader implements the path-based style of local reads
* first introduced in HDFS-2246.
*/
static BlockReader getLegacyBlockReaderLocal(UserGroupInformation ugi,
Configuration conf, String src, ExtendedBlock blk,
Token accessToken, DatanodeInfo chosenNode,
int socketTimeout, long offsetIntoBlock,
boolean connectToDnViaHostname) throws InvalidToken, IOException {
try {
return BlockReaderLocalLegacy.newBlockReader(ugi, conf, src, blk, accessToken,
chosenNode, socketTimeout, offsetIntoBlock, blk.getNumBytes()
- offsetIntoBlock, connectToDnViaHostname);
} catch (RemoteException re) {
throw re.unwrapRemoteException(InvalidToken.class,
AccessControlException.class);
}
}
}
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