Reduce number of ProjectMetadatas built during template validation (elastic#135214)

nielsbauman · web-flow · commit b8958b751007 · 2025-09-22T21:46:33.000+02:00
We're currently building `ProjectMetadata` instances with minor changes
a few times during the index/component template validation. On large
clusters with a large cluster state/project metadata, building a
`ProjectMetadata` becomes quite expensive. It turns out that we can do
the exact same validation without building all these intermediate
projects.

A follow-up PR will move some of the validation logic to the transport
action to reduce processing on the cluster state update thread.
diff --git a/server/src/main/java/org/elasticsearch/cluster/metadata/MetadataIndexTemplateService.java b/server/src/main/java/org/elasticsearch/cluster/metadata/MetadataIndexTemplateService.java
@@ -47,7 +47,6 @@
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.index.mapper.RoutingFieldMapper;
-import org.elasticsearch.index.shard.IndexLongFieldRange;
 import org.elasticsearch.indices.IndexTemplateMissingException;
 import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.indices.InvalidIndexTemplateException;
@@ -173,9 +172,12 @@ private abstract static class TemplateClusterStateUpdateTask implements ClusterS
         }
 
         public final ClusterState execute(ClusterState currentState) throws Exception {
-            ProjectMetadata metadata = currentState.metadata().getProject(projectId);
-            ProjectMetadata newMetadata = execute(metadata);
-            return metadata == newMetadata ? currentState : ClusterState.builder(currentState).putProjectMetadata(newMetadata).build();
+            ProjectMetadata currentProject = currentState.metadata().getProject(projectId);
+            ProjectMetadata newProject = execute(currentProject);
+            if (currentProject == newProject) {
+                return currentState;
+            }
+            return ClusterState.builder(currentState).metadata(currentState.metadata().withUpdatedProject(newProject)).build();
         }
 
         public abstract ProjectMetadata execute(ProjectMetadata currentProject) throws Exception;
@@ -384,19 +386,17 @@ public ProjectMetadata addComponentTemplate(
         }
 
         validateTemplate(finalSettings, wrappedMappings, indicesService);
-        validate(name, finalComponentTemplate);
+        validate(name, finalComponentTemplate.template(), List.of(), null);
 
+        ProjectMetadata projectWithComponentTemplateAdded = ProjectMetadata.builder(project).put(name, finalComponentTemplate).build();
         // Validate all composable index templates that use this component template
-        if (templatesUsingComponent.size() > 0) {
-            ProjectMetadata tempProjectWithComponentTemplateAdded = ProjectMetadata.builder(project)
-                .put(name, finalComponentTemplate)
-                .build();
+        if (templatesUsingComponent.isEmpty() == false) {
             Exception validationFailure = null;
             for (Map.Entry<String, ComposableIndexTemplate> entry : templatesUsingComponent.entrySet()) {
                 final String composableTemplateName = entry.getKey();
                 final ComposableIndexTemplate composableTemplate = entry.getValue();
                 try {
-                    validateIndexTemplateV2(tempProjectWithComponentTemplateAdded, composableTemplateName, composableTemplate);
+                    validateIndexTemplateV2(projectWithComponentTemplateAdded, composableTemplateName, composableTemplate);
                 } catch (Exception e) {
                     if (validationFailure == null) {
                         validationFailure = new IllegalArgumentException(
@@ -426,7 +426,7 @@ public ProjectMetadata addComponentTemplate(
         }
 
         logger.info("{} component template [{}]", existing == null ? "adding" : "updating", name);
-        return ProjectMetadata.builder(project).put(name, finalComponentTemplate).build();
+        return projectWithComponentTemplateAdded;
     }
 
     /**
@@ -784,8 +784,9 @@ void validateIndexTemplateV2(ProjectMetadata projectMetadata, String name, Compo
         var finalTemplate = indexTemplate.template();
         final var now = instantSource.instant();
 
-        final var combinedMappings = collectMappings(indexTemplate, projectMetadata.componentTemplates(), "tmp_idx");
-        final var combinedSettings = resolveSettings(indexTemplate, projectMetadata.componentTemplates());
+        final var componentTemplates = projectMetadata.componentTemplates();
+        final var combinedMappings = collectMappings(indexTemplate, componentTemplates, "tmp_idx");
+        final var combinedSettings = resolveSettings(indexTemplate, componentTemplates);
         var additionalSettingsBuilder = Settings.builder();
         ImmutableOpenMap.Builder<String, Map<String, String>> customMetadataBuilder = ImmutableOpenMap.builder();
         for (var provider : indexSettingProviders) {
@@ -820,11 +821,11 @@ void validateIndexTemplateV2(ProjectMetadata projectMetadata, String name, Compo
 
         validate(name, templateToValidate, additionalSettings);
         validateDataStreamsStillReferenced(projectMetadata, name, templateToValidate);
-        validateLifecycle(projectMetadata, name, templateToValidate, globalRetentionSettings.get(false));
-        validateDataStreamOptions(projectMetadata, name, templateToValidate, globalRetentionSettings.get(true));
+        validateLifecycle(componentTemplates, name, templateToValidate, globalRetentionSettings.get(false));
+        validateDataStreamOptions(componentTemplates, name, templateToValidate, globalRetentionSettings.get(true));
 
         if (templateToValidate.isDeprecated() == false) {
-            validateUseOfDeprecatedComponentTemplates(name, templateToValidate, projectMetadata.componentTemplates());
+            validateUseOfDeprecatedComponentTemplates(name, templateToValidate, componentTemplates);
             validateUseOfDeprecatedIngestPipelines(name, projectMetadata.custom(IngestMetadata.TYPE), combinedSettings);
             // TODO come up with a plan how to validate usage of deprecated ILM policies
             // we don't have access to the core/main plugin here so we can't use the IndexLifecycleMetadata type
@@ -900,12 +901,12 @@ private void emitWarningIfPipelineIsDeprecated(String name, Map<String, Pipeline
 
     // Visible for testing
     static void validateLifecycle(
-        ProjectMetadata project,
+        Map<String, ComponentTemplate> componentTemplates,
         String indexTemplateName,
         ComposableIndexTemplate template,
         @Nullable DataStreamGlobalRetention globalRetention
     ) {
-        DataStreamLifecycle.Builder builder = resolveLifecycle(template, project.componentTemplates());
+        DataStreamLifecycle.Builder builder = resolveLifecycle(template, componentTemplates);
         if (builder != null) {
             if (template.getDataStreamTemplate() == null) {
                 throw new IllegalArgumentException(
@@ -925,12 +926,12 @@ static void validateLifecycle(
 
     // Visible for testing
     static void validateDataStreamOptions(
-        ProjectMetadata projectMetadata,
+        Map<String, ComponentTemplate> componentTemplates,
         String indexTemplateName,
         ComposableIndexTemplate template,
         DataStreamGlobalRetention globalRetention
     ) {
-        DataStreamOptions.Builder dataStreamOptionsBuilder = resolveDataStreamOptions(template, projectMetadata.componentTemplates());
+        DataStreamOptions.Builder dataStreamOptionsBuilder = resolveDataStreamOptions(template, componentTemplates);
         if (dataStreamOptionsBuilder != null) {
             if (template.getDataStreamTemplate() == null) {
                 throw new IllegalArgumentException(
@@ -971,18 +972,18 @@ private static void validateDataStreamsStillReferenced(
             .map(Map.Entry::getKey)
             .collect(Collectors.toSet());
 
-        Function<ProjectMetadata, Set<String>> findUnreferencedDataStreams = meta -> {
+        Function<Map<String, ComposableIndexTemplate>, Set<String>> findUnreferencedDataStreams = composableTemplates -> {
             final Set<String> unreferenced = new HashSet<>();
             // For each data stream that we have, see whether it's covered by a different
             // template (which is great), or whether it's now uncovered by any template
             for (String dataStream : dataStreams) {
-                final String matchingTemplate = findV2Template(meta, dataStream, false);
+                final String matchingTemplate = findV2Template(project, composableTemplates.entrySet(), dataStream, false, false);
                 if (matchingTemplate == null) {
                     unreferenced.add(dataStream);
                 } else {
                     // We found a template that still matches, great! Buuuuttt... check whether it
                     // is a data stream template, as it's only useful if it has a data stream definition
-                    if (meta.templatesV2().get(matchingTemplate).getDataStreamTemplate() == null) {
+                    if (composableTemplates.get(matchingTemplate).getDataStreamTemplate() == null) {
                         unreferenced.add(dataStream);
                     }
                 }
@@ -991,12 +992,13 @@ private static void validateDataStreamsStillReferenced(
         };
 
         // Find data streams that are currently unreferenced
-        final Set<String> currentlyUnreferenced = findUnreferencedDataStreams.apply(project);
+        final Set<String> currentlyUnreferenced = findUnreferencedDataStreams.apply(project.templatesV2());
 
-        // Generate a metadata as if the new template were actually in the cluster state
-        final ProjectMetadata updatedMetadata = ProjectMetadata.builder(project).put(templateName, newTemplate).build();
+        // Generate a map as if the new template were actually in the cluster state
+        final var updatedTemplatesMap = new HashMap<>(project.templatesV2());
+        updatedTemplatesMap.put(templateName, newTemplate);
         // Find the data streams that would be unreferenced now that the template is updated/added
-        final Set<String> newlyUnreferenced = findUnreferencedDataStreams.apply(updatedMetadata);
+        final Set<String> newlyUnreferenced = findUnreferencedDataStreams.apply(updatedTemplatesMap);
 
         // If we found any data streams that used to be covered, but will no longer be covered by
         // changing this template, then blow up with as much helpful information as we can muster
@@ -1226,7 +1228,7 @@ static Set<String> dataStreamsExclusivelyUsingTemplates(final ProjectMetadata pr
                 return candidates.stream()
                     .noneMatch(
                         template -> templateNames.contains(template.v1()) == false
-                            && isGlobalAndHasIndexHiddenSetting(projectMetadata, template.v2(), template.v1()) == false
+                            && isGlobalAndHasIndexHiddenSetting(template.v2(), projectMetadata.componentTemplates()) == false
                     );
             })
             .map(DataStream::getName)
@@ -1514,7 +1516,7 @@ private static String findV2Template(
         // a restored index cluster state that modified a component template used by this global template such that it has this setting)
         // we will fail and the user will have to update the index template and remove this setting or update the corresponding component
         // template that contributes to the index template resolved settings
-        if (isGlobalAndHasIndexHiddenSetting(projectMetadata, winner, winnerName)) {
+        if (isGlobalAndHasIndexHiddenSetting(winner, projectMetadata.componentTemplates())) {
             throw new IllegalStateException(
                 "global index template ["
                     + winnerName
@@ -1586,12 +1588,11 @@ private static boolean areTemplatesSorted(Collection<Map.Entry<String, Composabl
     // Checks if a global template specifies the `index.hidden` setting. This check is important because a global
     // template shouldn't specify the `index.hidden` setting, we leave it up to the caller to handle this situation.
     private static boolean isGlobalAndHasIndexHiddenSetting(
-        ProjectMetadata projectMetadata,
         ComposableIndexTemplate template,
-        String templateName
+        Map<String, ComponentTemplate> componentTemplates
     ) {
         return anyMatch(template.indexPatterns(), Regex::isMatchAllPattern)
-            && IndexMetadata.INDEX_HIDDEN_SETTING.exists(resolveSettings(projectMetadata, templateName));
+            && IndexMetadata.INDEX_HIDDEN_SETTING.exists(resolveSettings(template, componentTemplates));
     }
 
     /**
@@ -1962,10 +1963,8 @@ private static void validateCompositeTemplate(
         final NamedXContentRegistry xContentRegistry,
         final SystemIndices systemIndices
     ) throws Exception {
-        final ProjectMetadata projectMetadataWithTemplate = ProjectMetadata.builder(project).put(templateName, template).build();
-
         final String temporaryIndexName = "validate-template-" + UUIDs.randomBase64UUID().toLowerCase(Locale.ROOT);
-        Settings resolvedSettings = resolveSettings(projectMetadataWithTemplate, templateName);
+        Settings resolvedSettings = resolveSettings(template, project.componentTemplates());
 
         // use the provided values, otherwise just pick valid dummy values
         int dummyPartitionSize = IndexMetadata.INDEX_ROUTING_PARTITION_SIZE_SETTING.get(resolvedSettings);
@@ -1985,23 +1984,17 @@ private static void validateCompositeTemplate(
             .build();
 
         // Validate index metadata (settings)
-        final ProjectMetadata projectMetadataWithIndex = ProjectMetadata.builder(projectMetadataWithTemplate)
-            .put(
-                IndexMetadata.builder(temporaryIndexName)
-                    // necessary to pass asserts in ClusterState constructor
-                    .eventIngestedRange(IndexLongFieldRange.UNKNOWN)
-                    .settings(finalResolvedSettings)
-                    .putCustom(customMetadata)
-            )
+        final IndexMetadata tmpIndexMetadata = IndexMetadata.builder(temporaryIndexName)
+            .settings(finalResolvedSettings)
+            .putCustom(customMetadata)
             .build();
-        final IndexMetadata tmpIndexMetadata = projectMetadataWithIndex.index(temporaryIndexName);
         indicesService.withTempIndexService(tmpIndexMetadata, tempIndexService -> {
             // Validate aliases
             MetadataCreateIndexService.resolveAndValidateAliases(
                 temporaryIndexName,
                 Collections.emptySet(),
-                MetadataIndexTemplateService.resolveAliases(projectMetadataWithIndex, templateName),
-                projectMetadataWithIndex,
+                MetadataIndexTemplateService.resolveAliases(project, template),
+                project,
                 // the context is only used for validation so it's fine to pass fake values for the
                 // shard id and the current timestamp
                 xContentRegistry,
@@ -2014,7 +2007,7 @@ private static void validateCompositeTemplate(
             String indexName = DataStream.BACKING_INDEX_PREFIX + temporaryIndexName;
             // Parse mappings to ensure they are valid after being composed
 
-            List<CompressedXContent> mappings = collectMappings(projectMetadataWithIndex, templateName, indexName);
+            List<CompressedXContent> mappings = collectMappings(template, project.componentTemplates(), indexName);
             try {
                 MapperService mapperService = tempIndexService.mapperService();
                 mapperService.merge(MapperService.SINGLE_MAPPING_NAME, mappings, MapperService.MergeReason.INDEX_TEMPLATE);
@@ -2061,10 +2054,6 @@ public static void validateTemplate(Settings validateSettings, CompressedXConten
         });
     }
 
-    public void validate(String name, ComponentTemplate template) {
-        validate(name, template.template(), Collections.emptyList(), null);
-    }
-
     private void validate(String name, ComposableIndexTemplate template, @Nullable Settings systemProvided) {
         validate(name, template.template(), template.indexPatterns(), systemProvided);
     }
diff --git a/server/src/test/java/org/elasticsearch/cluster/metadata/DataStreamLifecycleWithRetentionWarningsTests.java b/server/src/test/java/org/elasticsearch/cluster/metadata/DataStreamLifecycleWithRetentionWarningsTests.java
@@ -169,7 +169,7 @@ public void testValidateLifecycleIndexTemplateWithWarning() {
         HeaderWarning.setThreadContext(threadContext);
         TimeValue defaultRetention = randomTimeValue(2, 100, TimeUnit.DAYS);
         MetadataIndexTemplateService.validateLifecycle(
-            ProjectMetadata.builder(randomProjectIdOrDefault()).build(),
+            Map.of(),
             randomAlphaOfLength(10),
             ComposableIndexTemplate.builder()
                 .template(Template.builder().lifecycle(DataStreamLifecycle.Template.DATA_DEFAULT))
@@ -195,7 +195,7 @@ public void testValidateInternalDataStreamRetentionWithoutWarning() {
         HeaderWarning.setThreadContext(threadContext);
         TimeValue defaultRetention = randomTimeValue(2, 100, TimeUnit.DAYS);
         MetadataIndexTemplateService.validateLifecycle(
-            ProjectMetadata.builder(randomProjectIdOrDefault()).build(),
+            Map.of(),
             randomAlphaOfLength(10),
             ComposableIndexTemplate.builder()
                 .template(Template.builder().lifecycle(DataStreamLifecycle.Template.DATA_DEFAULT))
@@ -216,20 +216,16 @@ public void testValidateLifecycleComponentTemplateWithWarning() {
         HeaderWarning.setThreadContext(threadContext);
         TimeValue defaultRetention = randomTimeValue(2, 100, TimeUnit.DAYS);
         MetadataIndexTemplateService.validateLifecycle(
-            ProjectMetadata.builder(randomProjectIdOrDefault())
-                .componentTemplates(
-                    Map.of(
-                        "component-template",
-                        new ComponentTemplate(
-                            Template.builder()
-                                .lifecycle(DataStreamLifecycle.dataLifecycleBuilder().dataRetention(randomTimeValue(2, 100, TimeUnit.DAYS)))
-                                .build(),
-                            null,
-                            null
-                        )
-                    )
+            Map.of(
+                "component-template",
+                new ComponentTemplate(
+                    Template.builder()
+                        .lifecycle(DataStreamLifecycle.dataLifecycleBuilder().dataRetention(randomTimeValue(2, 100, TimeUnit.DAYS)))
+                        .build(),
+                    null,
+                    null
                 )
-                .build(),
+            ),
             randomAlphaOfLength(10),
             ComposableIndexTemplate.builder()
                 .template(Template.builder().lifecycle(DataStreamLifecycle.Template.DATA_DEFAULT))
