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Elasticsearch subproject :server
/*
* 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.cluster.metadata;
import org.elasticsearch.common.ParseField;
import org.elasticsearch.common.xcontent.ConstructingObjectParser;
import org.elasticsearch.common.xcontent.ObjectParser;
import org.elasticsearch.common.xcontent.ToXContent;
import org.elasticsearch.common.xcontent.ToXContentFragment;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.gateway.MetaDataStateFormat;
import org.elasticsearch.index.Index;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.stream.Collectors;
/**
* This class represents the manifest file, which is the entry point for reading meta data from disk.
* Metadata consists of global metadata and index metadata.
* When new version of metadata is written it's assigned some generation long value.
* Global metadata generation could be obtained by calling {@link #getGlobalGeneration()}.
* Index metadata generation could be obtained by calling {@link #getIndexGenerations()}.
*/
public class Manifest implements ToXContentFragment {
//TODO revisit missing and unknown constants once Zen2 BWC is ready
private static final long MISSING_GLOBAL_GENERATION = -1L;
private static final long MISSING_CURRENT_TERM = 0L;
private static final long UNKNOWN_CURRENT_TERM = MISSING_CURRENT_TERM;
private static final long MISSING_CLUSTER_STATE_VERSION = 0L;
private static final long UNKNOWN_CLUSTER_STATE_VERSION = MISSING_CLUSTER_STATE_VERSION;
private final long globalGeneration;
private final Map indexGenerations;
private final long currentTerm;
private final long clusterStateVersion;
public Manifest(long currentTerm, long clusterStateVersion, long globalGeneration, Map indexGenerations) {
this.currentTerm = currentTerm;
this.clusterStateVersion = clusterStateVersion;
this.globalGeneration = globalGeneration;
this.indexGenerations = indexGenerations;
}
public static Manifest unknownCurrentTermAndVersion(long globalGeneration, Map indexGenerations) {
return new Manifest(UNKNOWN_CURRENT_TERM, UNKNOWN_CLUSTER_STATE_VERSION, globalGeneration, indexGenerations);
}
/**
* Returns global metadata generation.
*/
public long getGlobalGeneration() {
return globalGeneration;
}
/**
* Returns map from {@link Index} to index metadata generation.
*/
public Map getIndexGenerations() {
return indexGenerations;
}
public long getCurrentTerm() {
return currentTerm;
}
public long getClusterStateVersion() {
return clusterStateVersion;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Manifest manifest = (Manifest) o;
return currentTerm == manifest.currentTerm &&
clusterStateVersion == manifest.clusterStateVersion &&
globalGeneration == manifest.globalGeneration &&
Objects.equals(indexGenerations, manifest.indexGenerations);
}
@Override
public int hashCode() {
return Objects.hash(currentTerm, clusterStateVersion, globalGeneration, indexGenerations);
}
@Override
public String toString() {
return "Manifest{" +
"currentTerm=" + currentTerm +
", clusterStateVersion=" + clusterStateVersion +
", globalGeneration=" + globalGeneration +
", indexGenerations=" + indexGenerations +
'}';
}
private static final String MANIFEST_FILE_PREFIX = "manifest-";
private static final ToXContent.Params MANIFEST_FORMAT_PARAMS = new ToXContent.MapParams(Collections.singletonMap("binary", "true"));
public static final MetaDataStateFormat FORMAT = new MetaDataStateFormat(MANIFEST_FILE_PREFIX) {
@Override
public void toXContent(XContentBuilder builder, Manifest state) throws IOException {
state.toXContent(builder, MANIFEST_FORMAT_PARAMS);
}
@Override
public Manifest fromXContent(XContentParser parser) throws IOException {
return Manifest.fromXContent(parser);
}
};
/*
* Code below this comment is for XContent parsing/generation
*/
private static final ParseField CURRENT_TERM_PARSE_FIELD = new ParseField("current_term");
private static final ParseField CLUSTER_STATE_VERSION_PARSE_FIELD = new ParseField("cluster_state_version");
private static final ParseField GENERATION_PARSE_FIELD = new ParseField("generation");
private static final ParseField INDEX_GENERATIONS_PARSE_FIELD = new ParseField("index_generations");
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.field(CURRENT_TERM_PARSE_FIELD.getPreferredName(), currentTerm);
builder.field(CLUSTER_STATE_VERSION_PARSE_FIELD.getPreferredName(), clusterStateVersion);
builder.field(GENERATION_PARSE_FIELD.getPreferredName(), globalGeneration);
builder.array(INDEX_GENERATIONS_PARSE_FIELD.getPreferredName(), indexEntryList().toArray());
return builder;
}
private static long requireNonNullElseDefault(Long value, long defaultValue) {
return value != null ? value : defaultValue;
}
private List indexEntryList() {
return indexGenerations.entrySet().stream().
map(entry -> new IndexEntry(entry.getKey(), entry.getValue())).
collect(Collectors.toList());
}
private static long currentTerm(Object[] manifestFields) {
return requireNonNullElseDefault((Long) manifestFields[0], MISSING_CURRENT_TERM);
}
private static long clusterStateVersion(Object[] manifestFields) {
return requireNonNullElseDefault((Long) manifestFields[1], MISSING_CLUSTER_STATE_VERSION);
}
private static long generation(Object[] manifestFields) {
return requireNonNullElseDefault((Long) manifestFields[2], MISSING_GLOBAL_GENERATION);
}
@SuppressWarnings("unchecked")
private static Map indices(Object[] manifestFields) {
List listOfIndices = (List) manifestFields[3];
return listOfIndices.stream().collect(Collectors.toMap(IndexEntry::getIndex, IndexEntry::getGeneration));
}
private static final ConstructingObjectParser PARSER = new ConstructingObjectParser<>(
"manifest",
manifestFields ->
new Manifest(currentTerm(manifestFields), clusterStateVersion(manifestFields), generation(manifestFields),
indices(manifestFields)));
static {
PARSER.declareLong(ConstructingObjectParser.constructorArg(), CURRENT_TERM_PARSE_FIELD);
PARSER.declareLong(ConstructingObjectParser.constructorArg(), CLUSTER_STATE_VERSION_PARSE_FIELD);
PARSER.declareLong(ConstructingObjectParser.constructorArg(), GENERATION_PARSE_FIELD);
PARSER.declareObjectArray(ConstructingObjectParser.constructorArg(), IndexEntry.INDEX_ENTRY_PARSER, INDEX_GENERATIONS_PARSE_FIELD);
}
public static Manifest fromXContent(XContentParser parser) throws IOException {
return PARSER.parse(parser, null);
}
public boolean isEmpty() {
return currentTerm == MISSING_CURRENT_TERM && clusterStateVersion == MISSING_CLUSTER_STATE_VERSION
&& globalGeneration == MISSING_GLOBAL_GENERATION && indexGenerations.isEmpty();
}
public static Manifest empty() {
return new Manifest(MISSING_CURRENT_TERM, MISSING_CLUSTER_STATE_VERSION, MISSING_GLOBAL_GENERATION, Collections.emptyMap());
}
public boolean isGlobalGenerationMissing() {
return globalGeneration == MISSING_GLOBAL_GENERATION;
}
private static final class IndexEntry implements ToXContentFragment {
private static final ParseField INDEX_GENERATION_PARSE_FIELD = new ParseField("generation");
private static final ParseField INDEX_PARSE_FIELD = new ParseField("index");
static final ConstructingObjectParser INDEX_ENTRY_PARSER = new ConstructingObjectParser<>(
"indexEntry",
indexAndGeneration -> new IndexEntry((Index) indexAndGeneration[0], (long) indexAndGeneration[1]));
static {
INDEX_ENTRY_PARSER.declareField(ConstructingObjectParser.constructorArg(),
Index::fromXContent, INDEX_PARSE_FIELD, ObjectParser.ValueType.OBJECT);
INDEX_ENTRY_PARSER.declareLong(ConstructingObjectParser.constructorArg(), INDEX_GENERATION_PARSE_FIELD);
}
private final long generation;
private final Index index;
IndexEntry(Index index, long generation) {
this.index = index;
this.generation = generation;
}
public long getGeneration() {
return generation;
}
public Index getIndex() {
return index;
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject();
builder.field(INDEX_PARSE_FIELD.getPreferredName(), index);
builder.field(GENERATION_PARSE_FIELD.getPreferredName(), generation);
builder.endObject();
return builder;
}
}
}