/*
* 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.repositories.blobstore;
import org.apache.lucene.codecs.CodecUtil;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.IndexFormatTooNewException;
import org.apache.lucene.index.IndexFormatTooOldException;
import org.apache.lucene.store.OutputStreamIndexOutput;
import org.elasticsearch.common.CheckedFunction;
import org.elasticsearch.common.blobstore.BlobContainer;
import org.elasticsearch.common.bytes.BytesArray;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.compress.CompressorFactory;
import org.elasticsearch.common.io.Streams;
import org.elasticsearch.common.io.stream.BytesStreamOutput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.lucene.store.ByteArrayIndexInput;
import org.elasticsearch.common.lucene.store.IndexOutputOutputStream;
import org.elasticsearch.common.xcontent.NamedXContentRegistry;
import org.elasticsearch.common.xcontent.ToXContent;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.gateway.CorruptStateException;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Locale;
/**
* Snapshot metadata file format used in v2.0 and above
*/
public class ChecksumBlobStoreFormat<T extends ToXContent> extends BlobStoreFormat<T> {
private static final String TEMP_FILE_PREFIX = "pending-";
private static final XContentType DEFAULT_X_CONTENT_TYPE = XContentType.SMILE;
// The format version
public static final int VERSION = 1;
private static final int BUFFER_SIZE = 4096;
protected final XContentType xContentType;
protected final boolean compress;
private final String codec;
/**
* @param codec codec name
* @param blobNameFormat format of the blobname in {@link String#format} format
* @param reader prototype object that can deserialize T from XContent
* @param compress true if the content should be compressed
* @param xContentType content type that should be used for write operations
*/
public ChecksumBlobStoreFormat(String codec, String blobNameFormat, CheckedFunction<XContentParser, T, IOException> reader,
NamedXContentRegistry namedXContentRegistry, boolean compress, XContentType xContentType) {
super(blobNameFormat, reader, namedXContentRegistry);
this.xContentType = xContentType;
this.compress = compress;
this.codec = codec;
}
/**
* @param codec codec name
* @param blobNameFormat format of the blobname in {@link String#format} format
* @param reader prototype object that can deserialize T from XContent
* @param compress true if the content should be compressed
*/
public ChecksumBlobStoreFormat(String codec, String blobNameFormat, CheckedFunction<XContentParser, T, IOException> reader,
NamedXContentRegistry namedXContentRegistry, boolean compress) {
this(codec, blobNameFormat, reader, namedXContentRegistry, compress, DEFAULT_X_CONTENT_TYPE);
}
/**
* Reads blob with specified name without resolving the blobName using using {@link #blobName} method.
*
* @param blobContainer blob container
* @param blobName blob name
*/
public T readBlob(BlobContainer blobContainer, String blobName) throws IOException {
try (InputStream inputStream = blobContainer.readBlob(blobName)) {
ByteArrayOutputStream out = new ByteArrayOutputStream();
Streams.copy(inputStream, out);
final byte[] bytes = out.toByteArray();
final String resourceDesc = "ChecksumBlobStoreFormat.readBlob(blob=\"" + blobName + "\")";
try (ByteArrayIndexInput indexInput = new ByteArrayIndexInput(resourceDesc, bytes)) {
CodecUtil.checksumEntireFile(indexInput);
CodecUtil.checkHeader(indexInput, codec, VERSION, VERSION);
long filePointer = indexInput.getFilePointer();
long contentSize = indexInput.length() - CodecUtil.footerLength() - filePointer;
BytesReference bytesReference = new BytesArray(bytes, (int) filePointer, (int) contentSize);
return read(bytesReference);
} catch (CorruptIndexException | IndexFormatTooOldException | IndexFormatTooNewException ex) {
// we trick this into a dedicated exception with the original stacktrace
throw new CorruptStateException(ex);
}
}
}
/**
* Writes blob in atomic manner with resolving the blob name using {@link #blobName} and {@link #tempBlobName} methods.
* <p>
* The blob will be compressed and checksum will be written if required.
*
* Atomic move might be very inefficient on some repositories. It also cannot override existing files.
*
* @param obj object to be serialized
* @param blobContainer blob container
* @param name blob name
*/
public void writeAtomic(T obj, BlobContainer blobContainer, String name) throws IOException {
String blobName = blobName(name);
String tempBlobName = tempBlobName(name);
writeBlob(obj, blobContainer, tempBlobName);
try {
blobContainer.move(tempBlobName, blobName);
} catch (IOException ex) {
// Move failed - try cleaning up
blobContainer.deleteBlob(tempBlobName);
throw ex;
}
}
/**
* Writes blob with resolving the blob name using {@link #blobName} method.
* <p>
* The blob will be compressed and checksum will be written if required.
*
* @param obj object to be serialized
* @param blobContainer blob container
* @param name blob name
*/
public void write(T obj, BlobContainer blobContainer, String name) throws IOException {
String blobName = blobName(name);
writeBlob(obj, blobContainer, blobName);
}
/**
* Writes blob in atomic manner without resolving the blobName using using {@link #blobName} method.
* <p>
* The blob will be compressed and checksum will be written if required.
*
* @param obj object to be serialized
* @param blobContainer blob container
* @param blobName blob name
*/
protected void writeBlob(T obj, BlobContainer blobContainer, String blobName) throws IOException {
BytesReference bytes = write(obj);
try (ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream()) {
final String resourceDesc = "ChecksumBlobStoreFormat.writeBlob(blob=\"" + blobName + "\")";
try (OutputStreamIndexOutput indexOutput = new OutputStreamIndexOutput(resourceDesc, blobName, byteArrayOutputStream, BUFFER_SIZE)) {
CodecUtil.writeHeader(indexOutput, codec, VERSION);
try (OutputStream indexOutputOutputStream = new IndexOutputOutputStream(indexOutput) {
@Override
public void close() throws IOException {
// this is important since some of the XContentBuilders write bytes on close.
// in order to write the footer we need to prevent closing the actual index input.
} }) {
bytes.writeTo(indexOutputOutputStream);
}
CodecUtil.writeFooter(indexOutput);
}
BytesArray bytesArray = new BytesArray(byteArrayOutputStream.toByteArray());
try (InputStream stream = bytesArray.streamInput()) {
blobContainer.writeBlob(blobName, stream, bytesArray.length());
}
}
}
/**
* Returns true if the blob is a leftover temporary blob.
*
* The temporary blobs might be left after failed atomic write operation.
*/
public boolean isTempBlobName(String blobName) {
return blobName.startsWith(ChecksumBlobStoreFormat.TEMP_FILE_PREFIX);
}
protected BytesReference write(T obj) throws IOException {
try (BytesStreamOutput bytesStreamOutput = new BytesStreamOutput()) {
if (compress) {
try (StreamOutput compressedStreamOutput = CompressorFactory.COMPRESSOR.streamOutput(bytesStreamOutput)) {
write(obj, compressedStreamOutput);
}
} else {
write(obj, bytesStreamOutput);
}
return bytesStreamOutput.bytes();
}
}
protected void write(T obj, StreamOutput streamOutput) throws IOException {
try (XContentBuilder builder = XContentFactory.contentBuilder(xContentType, streamOutput)) {
builder.startObject();
obj.toXContent(builder, SNAPSHOT_ONLY_FORMAT_PARAMS);
builder.endObject();
}
}
protected String tempBlobName(String name) {
return TEMP_FILE_PREFIX + String.format(Locale.ROOT, blobNameFormat, name);
}
}