org.apache.flink.runtime.blob.BlobUtils Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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,
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.runtime.blob;
import org.apache.flink.api.common.JobID;
import org.apache.flink.configuration.BlobServerOptions;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.ConfigurationUtils;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.core.fs.Path;
import org.apache.flink.runtime.highavailability.HighAvailabilityServicesUtils;
import org.apache.flink.runtime.jobmanager.HighAvailabilityMode;
import org.apache.flink.util.InstantiationUtil;
import org.apache.flink.util.StringUtils;
import org.slf4j.Logger;
import javax.annotation.Nullable;
import java.io.EOFException;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.nio.file.FileAlreadyExistsException;
import java.nio.file.Files;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Random;
import java.util.UUID;
/**
* Utility class to work with blob data.
*/
public class BlobUtils {
/**
* Algorithm to be used for calculating the BLOB keys.
*/
private static final String HASHING_ALGORITHM = "SHA-1";
/**
* The prefix of all BLOB files stored by the BLOB server.
*/
private static final String BLOB_FILE_PREFIX = "blob_";
/**
* The prefix of all job-specific directories created by the BLOB server.
*/
static final String JOB_DIR_PREFIX = "job_";
/**
* The prefix of all job-unrelated directories created by the BLOB server.
*/
static final String NO_JOB_DIR_PREFIX = "no_job";
private static final Random RANDOM = new Random();
/**
* Creates a BlobStore based on the parameters set in the configuration.
*
* @param config
* configuration to use
*
* @return a (distributed) blob store for high availability
*
* @throws IOException
* thrown if the (distributed) file storage cannot be created
*/
public static BlobStoreService createBlobStoreFromConfig(Configuration config) throws IOException {
if (HighAvailabilityMode.isHighAvailabilityModeActivated(config)) {
return createFileSystemBlobStore(config);
} else {
return new VoidBlobStore();
}
}
private static BlobStoreService createFileSystemBlobStore(Configuration configuration) throws IOException {
final Path clusterStoragePath = HighAvailabilityServicesUtils.getClusterHighAvailableStoragePath(configuration);
final FileSystem fileSystem;
try {
fileSystem = clusterStoragePath.getFileSystem();
} catch (Exception e) {
throw new IOException(
String.format("Could not create FileSystem for highly available storage path (%s)", clusterStoragePath),
e);
}
return new FileSystemBlobStore(fileSystem, clusterStoragePath.toUri().toString());
}
/**
* Creates a local storage directory for a blob service under the configuration parameter given
* by {@link BlobServerOptions#STORAGE_DIRECTORY}. If this is null or empty, we will
* fall back to Flink's temp directories (given by
* {@link org.apache.flink.configuration.CoreOptions#TMP_DIRS}) and choose one among them at
* random.
*
* @param config
* Flink configuration
*
* @return a new local storage directory
*
* @throws IOException
* thrown if the local file storage cannot be created or is not usable
*/
static File initLocalStorageDirectory(Configuration config) throws IOException {
String basePath = config.getString(BlobServerOptions.STORAGE_DIRECTORY);
File baseDir;
if (StringUtils.isNullOrWhitespaceOnly(basePath)) {
final String[] tmpDirPaths = ConfigurationUtils.parseTempDirectories(config);
baseDir = new File(tmpDirPaths[RANDOM.nextInt(tmpDirPaths.length)]);
}
else {
baseDir = new File(basePath);
}
File storageDir;
// NOTE: although we will be using UUIDs, there may be collisions
int maxAttempts = 10;
for (int attempt = 0; attempt < maxAttempts; attempt++) {
storageDir = new File(baseDir, String.format(
"blobStore-%s", UUID.randomUUID().toString()));
// Create the storage dir if it doesn't exist. Only return it when the operation was
// successful.
if (storageDir.mkdirs()) {
return storageDir;
}
}
// max attempts exceeded to find a storage directory
throw new IOException("Could not create storage directory for BLOB store in '" + baseDir + "'.");
}
/**
* Returns the BLOB service's directory for incoming (job-unrelated) files. The directory is
* created if it does not exist yet.
*
* @param storageDir
* storage directory used be the BLOB service
*
* @return the BLOB service's directory for incoming files
*
* @throws IOException
* if creating the directory fails
*/
static File getIncomingDirectory(File storageDir) throws IOException {
final File incomingDir = new File(storageDir, "incoming");
Files.createDirectories(incomingDir.toPath());
return incomingDir;
}
/**
* Returns the (designated) physical storage location of the BLOB with the given key.
*
* @param storageDir
* storage directory used be the BLOB service
* @param key
* the key identifying the BLOB
* @param jobId
* ID of the job for the incoming files (or null if job-unrelated)
*
* @return the (designated) physical storage location of the BLOB
*
* @throws IOException
* if creating the directory fails
*/
static File getStorageLocation(
File storageDir, @Nullable JobID jobId, BlobKey key) throws IOException {
File file = new File(getStorageLocationPath(storageDir.getAbsolutePath(), jobId, key));
Files.createDirectories(file.getParentFile().toPath());
return file;
}
/**
* Returns the BLOB server's storage directory for BLOBs belonging to the job with the given ID
* without creating the directory.
*
* @param storageDir
* storage directory used be the BLOB service
* @param jobId
* the ID of the job to return the storage directory for
*
* @return the storage directory for BLOBs belonging to the job with the given ID
*/
static String getStorageLocationPath(String storageDir, @Nullable JobID jobId) {
if (jobId == null) {
// format: $base/no_job
return String.format("%s/%s", storageDir, NO_JOB_DIR_PREFIX);
} else {
// format: $base/job_$jobId
return String.format("%s/%s%s", storageDir, JOB_DIR_PREFIX, jobId.toString());
}
}
/**
* Returns the path for the given blob key.
*
* The returned path can be used with the (local or HA) BLOB store file system back-end for
* recovery purposes and follows the same scheme as {@link #getStorageLocation(File, JobID,
* BlobKey)}.
*
* @param storageDir
* storage directory used be the BLOB service
* @param key
* the key identifying the BLOB
* @param jobId
* ID of the job for the incoming files
*
* @return the path to the given BLOB
*/
static String getStorageLocationPath(
String storageDir, @Nullable JobID jobId, BlobKey key) {
if (jobId == null) {
// format: $base/no_job/blob_$key
return String.format("%s/%s/%s%s",
storageDir, NO_JOB_DIR_PREFIX, BLOB_FILE_PREFIX, key.toString());
} else {
// format: $base/job_$jobId/blob_$key
return String.format("%s/%s%s/%s%s",
storageDir, JOB_DIR_PREFIX, jobId.toString(), BLOB_FILE_PREFIX, key.toString());
}
}
/**
* Creates a new instance of the message digest to use for the BLOB key computation.
*
* @return a new instance of the message digest to use for the BLOB key computation
*/
static MessageDigest createMessageDigest() {
try {
return MessageDigest.getInstance(HASHING_ALGORITHM);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Cannot instantiate the message digest algorithm " + HASHING_ALGORITHM, e);
}
}
/**
* Auxiliary method to write the length of an upcoming data chunk to an
* output stream.
*
* @param length
* the length of the upcoming data chunk in bytes
* @param outputStream
* the output stream to write the length to
* @throws IOException
* thrown if an I/O error occurs while writing to the output
* stream
*/
static void writeLength(int length, OutputStream outputStream) throws IOException {
byte[] buf = new byte[4];
buf[0] = (byte) (length & 0xff);
buf[1] = (byte) ((length >> 8) & 0xff);
buf[2] = (byte) ((length >> 16) & 0xff);
buf[3] = (byte) ((length >> 24) & 0xff);
outputStream.write(buf, 0, 4);
}
/**
* Auxiliary method to read the length of an upcoming data chunk from an
* input stream.
*
* @param inputStream
* the input stream to read the length from
* @return the length of the upcoming data chunk in bytes
* @throws IOException
* thrown if an I/O error occurs while reading from the input
* stream
*/
static int readLength(InputStream inputStream) throws IOException {
byte[] buf = new byte[4];
int bytesRead = 0;
while (bytesRead < 4) {
final int read = inputStream.read(buf, bytesRead, 4 - bytesRead);
if (read < 0) {
throw new EOFException("Read an incomplete length");
}
bytesRead += read;
}
bytesRead = buf[0] & 0xff;
bytesRead |= (buf[1] & 0xff) << 8;
bytesRead |= (buf[2] & 0xff) << 16;
bytesRead |= (buf[3] & 0xff) << 24;
return bytesRead;
}
/**
* Reads exception from given {@link InputStream}.
*
* @param in the input stream to read from
* @return exception that was read
* @throws IOException thrown if an I/O error occurs while reading from the input
* stream
*/
static Throwable readExceptionFromStream(InputStream in) throws IOException {
int len = readLength(in);
byte[] bytes = new byte[len];
readFully(in, bytes, 0, len, "Error message");
try {
return (Throwable) InstantiationUtil.deserializeObject(bytes, ClassLoader.getSystemClassLoader());
}
catch (ClassNotFoundException e) {
// should never occur
throw new IOException("Could not transfer error message", e);
}
}
/**
* Auxiliary method to read a particular number of bytes from an input stream. This method blocks until the
* requested number of bytes have been read from the stream. If the stream cannot offer enough data, an
* {@link EOFException} is thrown.
*
* @param inputStream The input stream to read the data from.
* @param buf The buffer to store the read data.
* @param off The offset inside the buffer.
* @param len The number of bytes to read from the stream.
* @param type The name of the type, to throw a good error message in case of not enough data.
* @throws IOException
* Thrown if I/O error occurs while reading from the stream or the stream cannot offer enough data.
*/
static void readFully(InputStream inputStream, byte[] buf, int off, int len, String type) throws IOException {
int bytesRead = 0;
while (bytesRead < len) {
final int read = inputStream.read(buf, off + bytesRead, len
- bytesRead);
if (read < 0) {
throw new EOFException("Received an incomplete " + type);
}
bytesRead += read;
}
}
static void closeSilently(Socket socket, Logger log) {
if (socket != null) {
try {
socket.close();
} catch (Throwable t) {
log.debug("Exception while closing BLOB server connection socket.", t);
}
}
}
/**
* Private constructor to prevent instantiation.
*/
private BlobUtils() {
throw new RuntimeException();
}
/**
* Moves the temporary incomingFile to its permanent location where it is available for
* use (not thread-safe!).
*
* @param incomingFile
* temporary file created during transfer
* @param jobId
* ID of the job this blob belongs to or null if job-unrelated
* @param blobKey
* BLOB key identifying the file
* @param storageFile
* (local) file where the blob is/should be stored
* @param log
* logger for debug information
* @param blobStore
* HA store (or null if unavailable)
*
* @throws IOException
* thrown if an I/O error occurs while moving the file or uploading it to the HA store
*/
static void moveTempFileToStore(
File incomingFile, @Nullable JobID jobId, BlobKey blobKey, File storageFile,
Logger log, @Nullable BlobStore blobStore) throws IOException {
try {
// first check whether the file already exists
if (!storageFile.exists()) {
try {
// only move the file if it does not yet exist
Files.move(incomingFile.toPath(), storageFile.toPath());
incomingFile = null;
} catch (FileAlreadyExistsException ignored) {
log.warn("Detected concurrent file modifications. This should only happen if multiple" +
"BlobServer use the same storage directory.");
// we cannot be sure at this point whether the file has already been uploaded to the blob
// store or not. Even if the blobStore might shortly be in an inconsistent state, we have
// to persist the blob. Otherwise we might not be able to recover the job.
}
if (blobStore != null) {
// only the one moving the incoming file to its final destination is allowed to upload the
// file to the blob store
blobStore.put(storageFile, jobId, blobKey);
}
} else {
log.warn("File upload for an existing file with key {} for job {}. This may indicate a duplicate upload or a hash collision. Ignoring newest upload.", blobKey, jobId);
}
storageFile = null;
} finally {
// we failed to either create the local storage file or to upload it --> try to delete the local file
// while still having the write lock
if (storageFile != null && !storageFile.delete() && storageFile.exists()) {
log.warn("Could not delete the storage file {}.", storageFile);
}
if (incomingFile != null && !incomingFile.delete() && incomingFile.exists()) {
log.warn("Could not delete the staging file {} for blob key {} and job {}.", incomingFile, blobKey, jobId);
}
}
}
}