Add template builder (#113444) (#113512)

Since we are enriching the component templates with more entries such as
the data stream lifecycle and in the future the data stream options, we
add a template builder to help with the code, especially tests.

To highlight the value and prepare for the PRs that will add the data
stream options to the template we replace calls to the constructor with
all arguments by the builder: - when there are aguements with null
values, or - when we copy another template and change only a few fields.

This prepares the ground, so when we add data stream options, we will
not need to edit all these places.

(cherry picked from commit 3d7904b)

Author: gmarouli

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamAutoshardingIT.java

@@ -502,7 +502,7 @@ static void putComposableIndexTemplate(String id, List<String> patterns, @Nullab
         request.indexTemplate(
             ComposableIndexTemplate.builder()
                 .indexPatterns(patterns)
-                .template(new Template(settings, null, null, null))
+                .template(Template.builder().settings(settings))
                 .dataStreamTemplate(new ComposableIndexTemplate.DataStreamTemplate())
                 .build()
         );

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamIT.java

@@ -2441,7 +2441,13 @@ static void putComposableIndexTemplate(
         request.indexTemplate(
             ComposableIndexTemplate.builder()
                 .indexPatterns(patterns)
-                .template(new Template(settings, mappings == null ? null : CompressedXContent.fromJSON(mappings), aliases, lifecycle))
+                .template(
+                    Template.builder()
+                        .settings(settings)
+                        .mappings(mappings == null ? null : CompressedXContent.fromJSON(mappings))
+                        .aliases(aliases)
+                        .lifecycle(lifecycle)
+                )
                 .metadata(metadata)
                 .dataStreamTemplate(new ComposableIndexTemplate.DataStreamTemplate(false, false, withFailureStore))
                 .build()

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/ResolveClusterDataStreamIT.java

@@ -453,7 +453,7 @@ void putComposableIndexTemplate(Client client, String id, List<String> patterns,
         request.indexTemplate(
             ComposableIndexTemplate.builder()
                 .indexPatterns(patterns)
-                .template(new Template(null, null, aliases, null))
+                .template(Template.builder().aliases(aliases))
                 .dataStreamTemplate(new ComposableIndexTemplate.DataStreamTemplate())
                 .build()
         );

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/lifecycle/CrudSystemDataStreamLifecycleIT.java

@@ -201,12 +201,10 @@ public Collection<SystemDataStreamDescriptor> getSystemDataStreamDescriptors() {
                         ComposableIndexTemplate.builder()
                             .indexPatterns(List.of(".test-data-stream"))
                             .template(
-                                new Template(
-                                    Settings.EMPTY,
-                                    mappings,
-                                    null,
-                                    DataStreamLifecycle.newBuilder().dataRetention(randomMillisUpToYear9999()).build()
-                                )
+                                Template.builder()
+                                    .settings(Settings.EMPTY)
+                                    .mappings(mappings)
+                                    .lifecycle(DataStreamLifecycle.newBuilder().dataRetention(randomMillisUpToYear9999()).build())
                             )
                             .dataStreamTemplate(new DataStreamTemplate())
                             .build(),

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/lifecycle/DataStreamLifecycleServiceIT.java

@@ -345,7 +345,7 @@ public void testOriginationDate() throws Exception {
         request.indexTemplate(
             ComposableIndexTemplate.builder()
                 .indexPatterns(List.of("index_*"))
-                .template(new Template(null, CompressedXContent.fromJSON(mapping), null, null))
+                .template(Template.builder().mappings(CompressedXContent.fromJSON(mapping)))
                 .build()
         );
         client().execute(TransportPutComposableIndexTemplateAction.TYPE, request).actionGet();
@@ -1221,7 +1221,12 @@ static void putComposableIndexTemplate(
         request.indexTemplate(
             ComposableIndexTemplate.builder()
                 .indexPatterns(patterns)
-                .template(new Template(settings, mappings == null ? null : CompressedXContent.fromJSON(mappings), null, lifecycle))
+                .template(
+                    Template.builder()
+                        .settings(settings)
+                        .mappings(mappings == null ? null : CompressedXContent.fromJSON(mappings))
+                        .lifecycle(lifecycle)
+                )
                 .metadata(metadata)
                 .dataStreamTemplate(new ComposableIndexTemplate.DataStreamTemplate(false, false, withFailureStore))
                 .build()
@@ -1268,14 +1273,12 @@ public Collection<SystemDataStreamDescriptor> getSystemDataStreamDescriptors() {
                         .dataStreamTemplate(new ComposableIndexTemplate.DataStreamTemplate())
                         .indexPatterns(List.of(DataStream.BACKING_INDEX_PREFIX + SYSTEM_DATA_STREAM_NAME + "*"))
                         .template(
-                            new Template(
-                                Settings.EMPTY,
-                                null,
-                                null,
-                                DataStreamLifecycle.newBuilder()
-                                    .dataRetention(TimeValue.timeValueDays(SYSTEM_DATA_STREAM_RETENTION_DAYS))
-                                    .build()
-                            )
+                            Template.builder()
+                                .settings(Settings.EMPTY)
+                                .lifecycle(
+                                    DataStreamLifecycle.newBuilder()
+                                        .dataRetention(TimeValue.timeValueDays(SYSTEM_DATA_STREAM_RETENTION_DAYS))
+                                )
                         )
                         .build(),
                     Map.of(),

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/lifecycle/ExplainDataStreamLifecycleIT.java

@@ -445,7 +445,12 @@ static void putComposableIndexTemplate(
         request.indexTemplate(
             ComposableIndexTemplate.builder()
                 .indexPatterns(patterns)
-                .template(new Template(settings, mappings == null ? null : CompressedXContent.fromJSON(mappings), null, lifecycle))
+                .template(
+                    Template.builder()
+                        .settings(settings)
+                        .mappings(mappings == null ? null : CompressedXContent.fromJSON(mappings))
+                        .lifecycle(lifecycle)
+                )
                 .metadata(metadata)
                 .dataStreamTemplate(new ComposableIndexTemplate.DataStreamTemplate())
                 .build()

modules/data-streams/src/test/java/org/elasticsearch/datastreams/lifecycle/DataStreamLifecycleFixtures.java

@@ -114,7 +114,12 @@ static void putComposableIndexTemplate(
         request.indexTemplate(
             ComposableIndexTemplate.builder()
                 .indexPatterns(patterns)
-                .template(new Template(settings, mappings == null ? null : CompressedXContent.fromJSON(mappings), null, lifecycle))
+                .template(
+                    Template.builder()
+                        .settings(settings)
+                        .mappings(mappings == null ? null : CompressedXContent.fromJSON(mappings))
+                        .lifecycle(lifecycle)
+                )
                 .metadata(metadata)
                 .dataStreamTemplate(new ComposableIndexTemplate.DataStreamTemplate())
                 .build()

server/src/main/java/org/elasticsearch/action/admin/indices/template/put/TransportPutComponentTemplateAction.java

@@ -78,7 +78,7 @@ public static ComponentTemplate normalizeComponentTemplate(
             Settings.Builder builder = Settings.builder().put(template.settings()).normalizePrefix(IndexMetadata.INDEX_SETTING_PREFIX);
             Settings settings = builder.build();
             indexScopedSettings.validate(settings, true);
-            template = new Template(settings, template.mappings(), template.aliases(), template.lifecycle());
+            template = Template.builder(template).settings(settings).build();
             componentTemplate = new ComponentTemplate(
                 template,
                 componentTemplate.version(),

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

@@ -537,6 +537,11 @@ public Builder template(Template template) {
             return this;
         }
 
+        public Builder template(Template.Builder template) {
+            this.template = template.build();
+            return this;
+        }
+
         public Builder componentTemplates(List<String> componentTemplates) {
             this.componentTemplates = componentTemplates;
             return this;

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

@@ -693,7 +693,7 @@ public static Map<String, List<String>> v2TemplateOverlaps(
     private void validateIndexTemplateV2(String name, ComposableIndexTemplate indexTemplate, ClusterState currentState) {
         // Workaround for the fact that start_time and end_time are injected by the MetadataCreateDataStreamService upon creation,
         // but when validating templates that create data streams the MetadataCreateDataStreamService isn't used.
-        var finalTemplate = Optional.ofNullable(indexTemplate.template());
+        var finalTemplate = indexTemplate.template();
         var finalSettings = Settings.builder();
         final var now = Instant.now();
         final var metadata = currentState.getMetadata();
@@ -717,18 +717,11 @@ private void validateIndexTemplateV2(String name, ComposableIndexTemplate indexT
         // Then apply setting from component templates:
         finalSettings.put(combinedSettings);
         // Then finally apply settings resolved from index template:
-        finalSettings.put(finalTemplate.map(Template::settings).orElse(Settings.EMPTY));
-
-        var templateToValidate = indexTemplate.toBuilder()
-            .template(
-                new Template(
-                    finalSettings.build(),
-                    finalTemplate.map(Template::mappings).orElse(null),
-                    finalTemplate.map(Template::aliases).orElse(null),
-                    finalTemplate.map(Template::lifecycle).orElse(null)
-                )
-            )
-            .build();
+        if (finalTemplate != null && finalTemplate.settings() != null) {
+            finalSettings.put(finalTemplate.settings());
+        }
+
+        var templateToValidate = indexTemplate.toBuilder().template(Template.builder(finalTemplate).settings(finalSettings)).build();
 
         validate(name, templateToValidate);
         validateDataStreamsStillReferenced(currentState, name, templateToValidate);