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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.blobstore.fs;
import org.apache.lucene.util.IOUtils;
import org.elasticsearch.common.blobstore.BlobMetaData;
import org.elasticsearch.common.blobstore.BlobPath;
import org.elasticsearch.common.blobstore.support.AbstractBlobContainer;
import org.elasticsearch.common.blobstore.support.PlainBlobMetaData;
import org.elasticsearch.common.io.Streams;
import java.io.BufferedInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.DirectoryStream;
import java.nio.file.FileAlreadyExistsException;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.StandardCopyOption;
import java.nio.file.StandardOpenOption;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.HashMap;
import java.util.Map;
import static java.util.Collections.unmodifiableMap;
/**
* A file system based implementation of {@link org.elasticsearch.common.blobstore.BlobContainer}.
* All blobs in the container are stored on a file system, the location of which is specified by the {@link BlobPath}.
*
* Note that the methods in this implementation of {@link org.elasticsearch.common.blobstore.BlobContainer} may
* additionally throw a {@link java.lang.SecurityException} if the configured {@link java.lang.SecurityManager}
* does not permit read and/or write access to the underlying files.
*/
public class FsBlobContainer extends AbstractBlobContainer {
protected final FsBlobStore blobStore;
protected final Path path;
public FsBlobContainer(FsBlobStore blobStore, BlobPath blobPath, Path path) {
super(blobPath);
this.blobStore = blobStore;
this.path = path;
}
@Override
public Map<String, BlobMetaData> listBlobs() throws IOException {
return listBlobsByPrefix(null);
}
@Override
public Map<String, BlobMetaData> listBlobsByPrefix(String blobNamePrefix) throws IOException {
// If we get duplicate files we should just take the last entry
Map<String, BlobMetaData> builder = new HashMap<>();
blobNamePrefix = blobNamePrefix == null ? "" : blobNamePrefix;
try (DirectoryStream<Path> stream = Files.newDirectoryStream(path, blobNamePrefix + "*")) {
for (Path file : stream) {
final BasicFileAttributes attrs = Files.readAttributes(file, BasicFileAttributes.class);
if (attrs.isRegularFile()) {
builder.put(file.getFileName().toString(), new PlainBlobMetaData(file.getFileName().toString(), attrs.size()));
}
}
}
return unmodifiableMap(builder);
}
@Override
public void deleteBlob(String blobName) throws IOException {
Path blobPath = path.resolve(blobName);
if (Files.isDirectory(blobPath)) {
// delete directory recursively as long as it is empty (only contains empty directories),
// which is the reason we aren't deleting any files, only the directories on the post-visit
Files.walkFileTree(blobPath, new SimpleFileVisitor<Path>() {
@Override
public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
Files.delete(dir);
return FileVisitResult.CONTINUE;
}
});
} else {
Files.delete(blobPath);
}
}
@Override
public boolean blobExists(String blobName) {
return Files.exists(path.resolve(blobName));
}
@Override
public InputStream readBlob(String name) throws IOException {
final Path resolvedPath = path.resolve(name);
try {
return new BufferedInputStream(Files.newInputStream(resolvedPath), blobStore.bufferSizeInBytes());
} catch (FileNotFoundException fnfe) {
throw new NoSuchFileException("[" + name + "] blob not found");
}
}
@Override
public void writeBlob(String blobName, InputStream inputStream, long blobSize) throws IOException {
if (blobExists(blobName)) {
throw new FileAlreadyExistsException("blob [" + blobName + "] already exists, cannot overwrite");
}
final Path file = path.resolve(blobName);
try (OutputStream outputStream = Files.newOutputStream(file, StandardOpenOption.CREATE_NEW)) {
Streams.copy(inputStream, outputStream, new byte[blobStore.bufferSizeInBytes()]);
}
IOUtils.fsync(file, false);
IOUtils.fsync(path, true);
}
@Override
public void move(String source, String target) throws IOException {
Path sourcePath = path.resolve(source);
Path targetPath = path.resolve(target);
// If the target file exists then Files.move() behaviour is implementation specific
// the existing file might be replaced or this method fails by throwing an IOException.
assert !Files.exists(targetPath);
Files.move(sourcePath, targetPath, StandardCopyOption.ATOMIC_MOVE);
IOUtils.fsync(path, true);
}
}