[7.x] Add ComponentTemplate to MetaData (#53290)

server/src/main/java/org/elasticsearch/cluster/ClusterModule.java

@@ -22,6 +22,7 @@
 import org.elasticsearch.cluster.action.index.MappingUpdatedAction;
 import org.elasticsearch.cluster.action.index.NodeMappingRefreshAction;
 import org.elasticsearch.cluster.action.shard.ShardStateAction;
+import org.elasticsearch.cluster.metadata.ComponentTemplateMetadata;
 import org.elasticsearch.cluster.metadata.IndexGraveyard;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.metadata.MetaData;
@@ -130,6 +131,8 @@ public static List<Entry> getNamedWriteables() {
         registerMetaDataCustom(entries, IndexGraveyard.TYPE, IndexGraveyard::new, IndexGraveyard::readDiffFrom);
         registerMetaDataCustom(entries, PersistentTasksCustomMetaData.TYPE, PersistentTasksCustomMetaData::new,
             PersistentTasksCustomMetaData::readDiffFrom);
+        registerMetaDataCustom(entries, ComponentTemplateMetadata.TYPE, ComponentTemplateMetadata::new,
+            ComponentTemplateMetadata::readDiffFrom);
         // Task Status (not Diffable)
         entries.add(new Entry(Task.Status.class, PersistentTasksNodeService.Status.NAME, PersistentTasksNodeService.Status::new));
         return entries;
@@ -177,6 +180,8 @@ public static List<NamedXContentRegistry.Entry> getNamedXWriteables() {
             IndexGraveyard::fromXContent));
         entries.add(new NamedXContentRegistry.Entry(MetaData.Custom.class, new ParseField(PersistentTasksCustomMetaData.TYPE),
             PersistentTasksCustomMetaData::fromXContent));
+        entries.add(new NamedXContentRegistry.Entry(MetaData.Custom.class, new ParseField(ComponentTemplateMetadata.TYPE),
+            ComponentTemplateMetadata::fromXContent));
         return entries;
     }
 

server/src/main/java/org/elasticsearch/cluster/metadata/ComponentTemplate.java

@@ -0,0 +1,300 @@
+/*
+ * 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.cluster.AbstractDiffable;
+import org.elasticsearch.cluster.Diff;
+import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.compress.CompressedXContent;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.ConstructingObjectParser;
+import org.elasticsearch.common.xcontent.ToXContentObject;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * A component template is a re-usable template as well as metadata about the template. Each
+ * component template is expected to be valid on its own. For example, if a component template
+ * contains a field "foo", it's expected to contain all the necessary settings/mappings/etc for the
+ * "foo" field. These component templates make up the individual pieces composing an index template.
+ */
+public class ComponentTemplate extends AbstractDiffable<ComponentTemplate> implements ToXContentObject {
+    private static final ParseField TEMPLATE = new ParseField("template");
+    private static final ParseField VERSION = new ParseField("version");
+    private static final ParseField METADATA = new ParseField("_meta");
+
+    @SuppressWarnings("unchecked")
+    private static final ConstructingObjectParser<ComponentTemplate, Void> PARSER =
+        new ConstructingObjectParser<>("component_template", false,
+            a -> new ComponentTemplate((Template) a[0], (Long) a[1], (Map<String, Object>) a[2]));
+
+    static {
+        PARSER.declareObject(ConstructingObjectParser.constructorArg(), Template.PARSER, TEMPLATE);
+        PARSER.declareLong(ConstructingObjectParser.optionalConstructorArg(), VERSION);
+        PARSER.declareObject(ConstructingObjectParser.optionalConstructorArg(), (p, c) -> p.map(), METADATA);
+    }
+
+    private final Template template;
+    @Nullable
+    private final Long version;
+    @Nullable
+    private final Map<String, Object> metadata;
+
+    static Diff<ComponentTemplate> readComponentTemplateDiffFrom(StreamInput in) throws IOException {
+        return AbstractDiffable.readDiffFrom(ComponentTemplate::new, in);
+    }
+
+    public static ComponentTemplate parse(XContentParser parser) {
+        return PARSER.apply(parser, null);
+    }
+
+    public ComponentTemplate(Template template, @Nullable Long version, @Nullable Map<String, Object> metadata) {
+        this.template = template;
+        this.version = version;
+        this.metadata = metadata;
+    }
+
+    public ComponentTemplate(StreamInput in) throws IOException {
+        this.template = new Template(in);
+        this.version = in.readOptionalVLong();
+        if (in.readBoolean()) {
+            this.metadata = in.readMap();
+        } else {
+            this.metadata = null;
+        }
+    }
+
+    public Template template() {
+        return template;
+    }
+
+    @Nullable
+    public Long version() {
+        return version;
+    }
+
+    @Nullable
+    public Map<String, Object> metadata() {
+        return metadata;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        this.template.writeTo(out);
+        out.writeOptionalVLong(this.version);
+        if (this.metadata == null) {
+            out.writeBoolean(false);
+        } else {
+            out.writeBoolean(true);
+            out.writeMap(this.metadata);
+        }
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(template, version, metadata);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (obj.getClass() != getClass()) {
+            return false;
+        }
+        ComponentTemplate other = (ComponentTemplate) obj;
+        return Objects.equals(template, other.template) &&
+            Objects.equals(version, other.version) &&
+            Objects.equals(metadata, other.metadata);
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(this);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field(TEMPLATE.getPreferredName(), this.template);
+        if (this.version != null) {
+            builder.field(VERSION.getPreferredName(), this.version);
+        }
+        if (this.metadata != null) {
+            builder.field(METADATA.getPreferredName(), this.metadata);
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    static class Template extends AbstractDiffable<Template> implements ToXContentObject {
+        private static final ParseField SETTINGS = new ParseField("settings");
+        private static final ParseField MAPPINGS = new ParseField("mappings");
+        private static final ParseField ALIASES = new ParseField("aliases");
+
+        @SuppressWarnings("unchecked")
+        private static final ConstructingObjectParser<Template, Void> PARSER = new ConstructingObjectParser<>("template", false,
+            a -> new Template((Settings) a[0], (CompressedXContent) a[1], (Map<String, AliasMetaData>) a[2]));
+
+        static {
+            PARSER.declareObject(ConstructingObjectParser.optionalConstructorArg(), (p, c) -> Settings.fromXContent(p), SETTINGS);
+            PARSER.declareObject(ConstructingObjectParser.optionalConstructorArg(), (p, c) ->
+                new CompressedXContent(Strings.toString(XContentFactory.jsonBuilder().map(p.mapOrdered()))), MAPPINGS);
+            PARSER.declareObject(ConstructingObjectParser.optionalConstructorArg(), (p, c) -> {
+                Map<String, AliasMetaData> aliasMap = new HashMap<>();
+                while ((p.nextToken()) != XContentParser.Token.END_OBJECT) {
+                    AliasMetaData alias = AliasMetaData.Builder.fromXContent(p);
+                    aliasMap.put(alias.alias(), alias);
+                }
+                return aliasMap;
+            }, ALIASES);
+        }
+
+        @Nullable
+        private final Settings settings;
+        @Nullable
+        private final CompressedXContent mappings;
+        @Nullable
+        private final Map<String, AliasMetaData> aliases;
+
+        Template(@Nullable Settings settings, @Nullable CompressedXContent mappings, @Nullable Map<String, AliasMetaData> aliases) {
+            this.settings = settings;
+            this.mappings = mappings;
+            this.aliases = aliases;
+        }
+
+        Template(StreamInput in) throws IOException {
+            if (in.readBoolean()) {
+                this.settings = Settings.readSettingsFromStream(in);
+            } else {
+                this.settings = null;
+            }
+            if (in.readBoolean()) {
+                this.mappings = CompressedXContent.readCompressedString(in);
+            } else {
+                this.mappings = null;
+            }
+            if (in.readBoolean()) {
+                this.aliases = in.readMap(StreamInput::readString, AliasMetaData::new);
+            } else {
+                this.aliases = null;
+            }
+        }
+
+        public Settings settings() {
+            return settings;
+        }
+
+        public CompressedXContent mappings() {
+            return mappings;
+        }
+
+        public Map<String, AliasMetaData> aliases() {
+            return aliases;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            if (this.settings == null) {
+                out.writeBoolean(false);
+            } else {
+                out.writeBoolean(true);
+                Settings.writeSettingsToStream(this.settings, out);
+            }
+            if (this.mappings == null) {
+                out.writeBoolean(false);
+            } else {
+                out.writeBoolean(true);
+                this.mappings.writeTo(out);
+            }
+            if (this.aliases == null) {
+                out.writeBoolean(false);
+            } else {
+                out.writeBoolean(true);
+                out.writeMap(this.aliases, StreamOutput::writeString, (stream, aliasMetaData) -> aliasMetaData.writeTo(stream));
+            }
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(settings, mappings, aliases);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null) {
+                return false;
+            }
+            if (obj.getClass() != getClass()) {
+                return false;
+            }
+            Template other = (Template) obj;
+            return Objects.equals(settings, other.settings) &&
+                Objects.equals(mappings, other.mappings) &&
+                Objects.equals(aliases, other.aliases);
+        }
+
+        @Override
+        public String toString() {
+            return Strings.toString(this);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject();
+            if (this.settings != null) {
+                builder.startObject(SETTINGS.getPreferredName());
+                this.settings.toXContent(builder, params);
+                builder.endObject();
+            }
+            if (this.mappings != null) {
+                Map<String, Object> uncompressedMapping =
+                    XContentHelper.convertToMap(new BytesArray(this.mappings.uncompressed()), true, XContentType.JSON).v2();
+                if (uncompressedMapping.size() > 0) {
+                    builder.field(MAPPINGS.getPreferredName());
+                    builder.map(uncompressedMapping);
+                }
+            }
+            if (this.aliases != null) {
+                builder.startObject(ALIASES.getPreferredName());
+                for (AliasMetaData alias : this.aliases.values()) {
+                    AliasMetaData.Builder.toXContent(alias, builder, params);
+                }
+                builder.endObject();
+            }
+            builder.endObject();
+            return builder;
+        }
+    }
+}