/*
* 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.elasticsearch.cluster.metadata.MetaData;
import org.elasticsearch.common.CheckedFunction;
import org.elasticsearch.common.blobstore.BlobContainer;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.xcontent.NamedXContentRegistry;
import org.elasticsearch.common.xcontent.ToXContent;
import org.elasticsearch.common.xcontent.XContentHelper;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.snapshots.SnapshotInfo;
import java.io.IOException;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
/**
* Base class that handles serialization of various data structures during snapshot/restore operations.
*/
public abstract class BlobStoreFormat<T extends ToXContent> {
protected final String blobNameFormat;
protected final CheckedFunction<XContentParser, T, IOException> reader;
protected final NamedXContentRegistry namedXContentRegistry;
// Serialization parameters to specify correct context for metadata serialization
protected static final ToXContent.Params SNAPSHOT_ONLY_FORMAT_PARAMS;
static {
Map<String, String> snapshotOnlyParams = new HashMap<>();
// when metadata is serialized certain elements of the metadata shouldn't be included into snapshot
// exclusion of these elements is done by setting MetaData.CONTEXT_MODE_PARAM to MetaData.CONTEXT_MODE_SNAPSHOT
snapshotOnlyParams.put(MetaData.CONTEXT_MODE_PARAM, MetaData.CONTEXT_MODE_SNAPSHOT);
// serialize SnapshotInfo using the SNAPSHOT mode
snapshotOnlyParams.put(SnapshotInfo.CONTEXT_MODE_PARAM, SnapshotInfo.CONTEXT_MODE_SNAPSHOT);
SNAPSHOT_ONLY_FORMAT_PARAMS = new ToXContent.MapParams(snapshotOnlyParams);
}
/**
* @param blobNameFormat format of the blobname in {@link String#format(Locale, String, Object...)} format
* @param reader the prototype object that can deserialize objects with type T
*/
protected BlobStoreFormat(String blobNameFormat, CheckedFunction<XContentParser, T, IOException> reader,
NamedXContentRegistry namedXContentRegistry) {
this.reader = reader;
this.blobNameFormat = blobNameFormat;
this.namedXContentRegistry = namedXContentRegistry;
}
/**
* Reads and parses the blob with given blob name.
*
* @param blobContainer blob container
* @param blobName blob name
* @return parsed blob object
*/
public abstract T readBlob(BlobContainer blobContainer, String blobName) throws IOException;
/**
* Reads and parses the blob with given name, applying name translation using the {link #blobName} method
*
* @param blobContainer blob container
* @param name name to be translated into
* @return parsed blob object
*/
public T read(BlobContainer blobContainer, String name) throws IOException {
String blobName = blobName(name);
return readBlob(blobContainer, blobName);
}
/**
* Deletes obj in the blob container
*/
public void delete(BlobContainer blobContainer, String name) throws IOException {
blobContainer.deleteBlob(blobName(name));
}
/**
* Checks obj in the blob container
*/
public boolean exists(BlobContainer blobContainer, String name) throws IOException {
return blobContainer.blobExists(blobName(name));
}
protected String blobName(String name) {
return String.format(Locale.ROOT, blobNameFormat, name);
}
protected T read(BytesReference bytes) throws IOException {
try (XContentParser parser = XContentHelper.createParser(namedXContentRegistry, bytes)) {
T obj = reader.apply(parser);
return obj;
}
}
}