org.elasticsearch.index.translog.TranslogStreams Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of org.apache.servicemix.bundles.elasticsearch
Show all versions of org.apache.servicemix.bundles.elasticsearch
This OSGi bundle wraps ${pkgArtifactId} ${pkgVersion} jar file.
/*
* 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.index.translog;
import org.apache.lucene.codecs.CodecUtil;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.store.InputStreamDataInput;
import org.elasticsearch.common.io.stream.InputStreamStreamInput;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
/**
* Encapsulating class used for operating on translog streams. Static methods
* on this class use the latest version of the stream.
*/
public class TranslogStreams {
/** V0, no header, no checksums */
public static TranslogStream LEGACY_TRANSLOG_STREAM = new LegacyTranslogStream();
/** V1, header, with per-op checksums */
public static TranslogStream CHECKSUMMED_TRANSLOG_STREAM = new ChecksummedTranslogStream();
public static TranslogStream LATEST = CHECKSUMMED_TRANSLOG_STREAM;
public static final String TRANSLOG_CODEC = "translog";
private static final byte LUCENE_CODEC_HEADER_BYTE = 0x3f;
private static final byte UNVERSIONED_TRANSLOG_HEADER_BYTE = 0x00;
/**
* Returns a new empty translog operation for the given {@link Translog.Operation.Type}
*/
static Translog.Operation newOperationFromType(Translog.Operation.Type type) throws IOException {
switch (type) {
case CREATE:
return new Translog.Create();
case DELETE:
return new Translog.Delete();
case DELETE_BY_QUERY:
return new Translog.DeleteByQuery();
case SAVE:
return new Translog.Index();
default:
throw new IOException("No type for [" + type + "]");
}
}
/**
* Read the next {@link Translog.Operation} from the stream using the
* latest translog version
*/
public static Translog.Operation readTranslogOperation(StreamInput in) throws IOException {
return LATEST.read(in);
}
/**
* Write the {@link Translog.Operation} to the output stream using the
* latest translog version
*/
public static void writeTranslogOperation(StreamOutput out, Translog.Operation op) throws IOException {
LATEST.write(out, op);
}
/**
* Given a file, return a VersionedTranslogStream based on an
* optionally-existing header in the file. If the file does not exist, or
* has zero length, returns the latest version. If the header does not
* exist, assumes Version 0 of the translog file format.
*
* The caller is responsible for closing the TranslogStream.
*
* @throws IOException
*/
public static TranslogStream translogStreamFor(File translogFile) throws IOException {
try (InputStreamStreamInput headerStream = new InputStreamStreamInput(new FileInputStream(translogFile));) {
if (translogFile.exists() == false || translogFile.length() == 0) {
// if it doesn't exist or has no data, use the latest version,
// there aren't any backwards compatibility issues
return CHECKSUMMED_TRANSLOG_STREAM;
}
// Lucene's CodecUtil writes a magic number of 0x3FD76C17 with the
// header, in binary this looks like:
//
// binary: 0011 1111 1101 0111 0110 1100 0001 0111
// hex : 3 f d 7 6 c 1 7
//
// With version 0 of the translog, the first byte is the
// Operation.Type, which will always be between 0-4, so we know if
// we grab the first byte, it can be:
// 0x3f => Lucene's magic number, so we can assume it's version 1 or later
// 0x00 => version 0 of the translog
//
// otherwise the first byte of the translog is corrupted and we
// should bail
byte b1 = headerStream.readByte();
if (b1 == LUCENE_CODEC_HEADER_BYTE) {
// Read 3 more bytes, meaning a whole integer has been read
byte b2 = headerStream.readByte();
byte b3 = headerStream.readByte();
byte b4 = headerStream.readByte();
// Convert the 4 bytes that were read into an integer
int header = ((b1 & 0xFF) << 24) + ((b2 & 0xFF) << 16) + ((b3 & 0xFF) << 8) + ((b4 & 0xFF) << 0);
// We confirm CodecUtil's CODEC_MAGIC number (0x3FD76C17)
// ourselves here, because it allows us to read the first
// byte separately
if (header != CodecUtil.CODEC_MAGIC) {
throw new TranslogCorruptedException("translog looks like version 1 or later, but has corrupted header");
}
// Confirm the rest of the header using CodecUtil, extracting
// the translog version
int version = CodecUtil.checkHeaderNoMagic(new InputStreamDataInput(headerStream), TRANSLOG_CODEC, 1, Integer.MAX_VALUE);
switch (version) {
case ChecksummedTranslogStream.VERSION:
return CHECKSUMMED_TRANSLOG_STREAM;
default:
throw new TranslogCorruptedException("No known translog stream version: " + version);
}
} else if (b1 == UNVERSIONED_TRANSLOG_HEADER_BYTE) {
return LEGACY_TRANSLOG_STREAM;
} else {
throw new TranslogCorruptedException("Invalid first byte in translog file, got: " + Long.toHexString(b1) + ", expected 0x00 or 0x3f");
}
} catch (CorruptIndexException e) {
throw new TranslogCorruptedException("Translog header corrupted", e);
}
}
}