Feed the settings from non-overruling providers to overruling ones.

server/src/main/java/org/elasticsearch/action/admin/indices/template/post/TransportSimulateIndexTemplateAction.java

@@ -285,7 +285,7 @@ public static Template resolveTemplate(
             MetadataCreateIndexService.validateAdditionalSettings(provider, result, additionalSettings);
             dummySettings.put(result);
             additionalSettings.put(result);
-            if (provider.overrulesTemplateAndRequestSettings()) {
+            if (provider.overrulesSettings()) {
                 overrulingSettings.addAll(result.keySet());
             }
         }

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

@@ -980,34 +980,55 @@ static Settings aggregateIndexSettings(
 
         final Settings.Builder indexSettingsBuilder = Settings.builder();
         if (sourceMetadata == null) {
-            final Settings templateAndRequestSettings = Settings.builder().put(combinedTemplateSettings).put(request.settings()).build();
+            final Settings.Builder settingsBuilder = Settings.builder().put(combinedTemplateSettings).put(request.settings());
+            final Settings templateAndRequestSettings = settingsBuilder.build();
 
             final IndexMode templateIndexMode = Optional.of(request)
                 .filter(r -> r.isFailureIndex() == false)
                 .map(CreateIndexClusterStateUpdateRequest::matchingTemplate)
                 .map(metadata::retrieveIndexModeFromTemplate)
                 .orElse(null);
 
-            // Loop through all the explicit index setting providers, adding them to the
+            // Loop through non-overruling setting providers, adding them to the
             // additionalIndexSettings map
             final Settings.Builder additionalIndexSettings = Settings.builder();
             final var resolvedAt = Instant.ofEpochMilli(request.getNameResolvedAt());
-            Set<String> overrulingSettings = new HashSet<>();
             for (IndexSettingProvider provider : indexSettingProviders) {
+                if (provider.overrulesSettings()) {
+                    continue;
+                }
                 var newAdditionalSettings = provider.getAdditionalIndexSettings(
                     request.index(),
                     request.dataStreamName(),
                     templateIndexMode,
-                    currentState.getMetadata(),
+                    metadata,
                     resolvedAt,
                     templateAndRequestSettings,
                     combinedTemplateMappings
                 );
                 validateAdditionalSettings(provider, newAdditionalSettings, additionalIndexSettings);
                 additionalIndexSettings.put(newAdditionalSettings);
-                if (provider.overrulesTemplateAndRequestSettings()) {
-                    overrulingSettings.addAll(newAdditionalSettings.keySet());
+            }
+
+            // Feed the settings generated by non-overruling to overruling setting providers,
+            // along with template and request settings.
+            final Settings templateAndRequestAndProviderSettings = settingsBuilder.put(additionalIndexSettings.build()).build();
+            Set<String> overrulingSettings = new HashSet<>();
+            for (IndexSettingProvider provider : indexSettingProviders) {
+                if (provider.overrulesSettings() == false) {
+                    continue;
                 }
+                var newAdditionalSettings = provider.getAdditionalIndexSettings(
+                    request.index(),
+                    request.dataStreamName(),
+                    templateIndexMode,
+                    metadata,
+                    resolvedAt,
+                    templateAndRequestAndProviderSettings,
+                    combinedTemplateMappings
+                );
+                additionalIndexSettings.put(newAdditionalSettings);
+                overrulingSettings.addAll(newAdditionalSettings.keySet());
             }
 
             for (String explicitSetting : additionalIndexSettings.keys()) {

server/src/main/java/org/elasticsearch/index/IndexSettingProvider.java

@@ -37,8 +37,9 @@ public interface IndexSettingProvider {
      *                                              otherwise <code>null</code> is returned.
      * @param metadata                              The current metadata instance that doesn't yet contain the index to be created
      * @param resolvedAt                            The time the request to create this new index was accepted.
-     * @param indexTemplateAndCreateRequestSettings All the settings resolved from the template that matches and any settings
-     *                                              defined on the create index request
+     * @param incomingSettings                      All the settings resolved from the templates that match, the create index request,
+     *                                              and from non-overruling providers if this is an overruling one
+     *                                              per {@link #overrulesSettings()}
      * @param combinedTemplateMappings              All the mappings resolved from the template that matches
      */
     Settings getAdditionalIndexSettings(
@@ -47,7 +48,7 @@ Settings getAdditionalIndexSettings(
         @Nullable IndexMode templateIndexMode,
         Metadata metadata,
         Instant resolvedAt,
-        Settings indexTemplateAndCreateRequestSettings,
+        Settings incomingSettings,
         List<CompressedXContent> combinedTemplateMappings
     );
 
@@ -59,13 +60,16 @@ record Parameters(CheckedFunction<IndexMetadata, MapperService, IOException> map
     }
 
     /**
-     * Indicates whether the additional settings that this provider returns can overrule the settings defined in matching template
-     * or in create index request.
+     * Indicates whether the additional settings that this provider returns can overrule the settings defined in
+     * matching templates, create index request, and settings returned by non-overruling providers. All these
+     * settings are included as input to
+     * {@link #getAdditionalIndexSettings(String, String, IndexMode, Metadata, Instant, Settings, List)}
+     * and can therefore be used to decide what settings to provide/overwrite.
      *
      * Note that this is not used during index template validation, to avoid overruling template settings that may apply to
      * different contexts (e.g. the provider is not used, or it returns different setting values).
      */
-    default boolean overrulesTemplateAndRequestSettings() {
+    default boolean overrulesSettings() {
         return false;
     }
 }

server/src/test/java/org/elasticsearch/action/admin/indices/template/post/TransportSimulateIndexTemplateActionTests.java

@@ -95,7 +95,7 @@ public Settings getAdditionalIndexSettings(
             }
 
             @Override
-            public boolean overrulesTemplateAndRequestSettings() {
+            public boolean overrulesSettings() {
                 return true;
             }
         });

server/src/test/java/org/elasticsearch/cluster/metadata/MetadataCreateIndexServiceTests.java

@@ -726,7 +726,7 @@ public Settings getAdditionalIndexSettings(
                 }
 
                 @Override
-                public boolean overrulesTemplateAndRequestSettings() {
+                public boolean overrulesSettings() {
                     return true;
                 }
             })
@@ -769,7 +769,7 @@ public Settings getAdditionalIndexSettings(
                 }
 
                 @Override
-                public boolean overrulesTemplateAndRequestSettings() {
+                public boolean overrulesSettings() {
                     return true;
                 }
             })
@@ -812,7 +812,7 @@ public Settings getAdditionalIndexSettings(
                 }
 
                 @Override
-                public boolean overrulesTemplateAndRequestSettings() {
+                public boolean overrulesSettings() {
                     return true;
                 }
             })
@@ -855,7 +855,7 @@ public Settings getAdditionalIndexSettings(
                 }
 
                 @Override
-                public boolean overrulesTemplateAndRequestSettings() {
+                public boolean overrulesSettings() {
                     return true;
                 }
             })
@@ -866,6 +866,66 @@ public boolean overrulesTemplateAndRequestSettings() {
         assertThat(aggregatedIndexSettings.get("other_setting"), equalTo("other_value"));
     }
 
+    public void testAggregateSettingsProviderUsesSettingsFromProvider() {
+        IndexTemplateMetadata templateMetadata = addMatchingTemplate(builder -> {
+            builder.settings(Settings.builder().put("template_setting", "value1"));
+        });
+        Metadata metadata = new Metadata.Builder().templates(Map.of("template_1", templateMetadata)).build();
+        ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT).metadata(metadata).build();
+        request.settings(Settings.builder().put("request_setting", "value2").build());
+
+        Settings aggregatedIndexSettings = aggregateIndexSettings(
+            clusterState,
+            request,
+            templateMetadata.settings(),
+            null,
+            null,
+            Settings.EMPTY,
+            IndexScopedSettings.DEFAULT_SCOPED_SETTINGS,
+            randomShardLimitService(),
+            Set.of(new IndexSettingProvider() {
+                @Override
+                public Settings getAdditionalIndexSettings(
+                    String indexName,
+                    String dataStreamName,
+                    IndexMode templateIndexMode,
+                    Metadata metadata,
+                    Instant resolvedAt,
+                    Settings incomingSettings,
+                    List<CompressedXContent> combinedTemplateMappings
+                ) {
+                    return Settings.builder().put("provided_setting_1", "value_3").put("provided_setting_2", "value_4").build();
+                }
+            }, new IndexSettingProvider() {
+                @Override
+                public Settings getAdditionalIndexSettings(
+                    String indexName,
+                    String dataStreamName,
+                    IndexMode templateIndexMode,
+                    Metadata metadata,
+                    Instant resolvedAt,
+                    Settings incomingSettings,
+                    List<CompressedXContent> combinedTemplateMappings
+                ) {
+                    if (incomingSettings.hasValue("provided_setting_1")) {
+                        return Settings.builder().put("provided_setting_2", "value_6").put("request_setting", "value_5").build();
+                    }
+                    return Settings.builder().put("request_setting", "value_5").build();
+                }
+
+                @Override
+                public boolean overrulesSettings() {
+                    return true;
+                }
+            })
+        );
+
+        assertThat(aggregatedIndexSettings.get("template_setting"), equalTo("value1"));
+        assertThat(aggregatedIndexSettings.get("request_setting"), equalTo("value_5"));
+        assertThat(aggregatedIndexSettings.get("provided_setting_1"), equalTo("value_3"));
+        assertThat(aggregatedIndexSettings.get("provided_setting_2"), equalTo("value_6"));
+    }
+
     public void testInvalidAliasName() {
         final String[] invalidAliasNames = new String[] { "-alias1", "+alias2", "_alias3", "a#lias", "al:ias", ".", ".." };
         String aliasName = randomFrom(invalidAliasNames);

server/src/test/java/org/elasticsearch/index/IndexSettingProviderTests.java

@@ -33,13 +33,14 @@ public void testIndexCreation() throws Exception {
         assertTrue(indexService.getIndexSettings().getSettings().hasValue("index.refresh_interval"));
         assertEquals("10", indexService.getIndexSettings().getSettings().get("index.mapping.depth.limit"));
 
-        INDEX_SETTING_OVERRULING.set(true);
+        INDEX_SETTING_PROVIDER2_ENABLED.set(true);
         indexService = createIndex("my-index3", settings);
         assertTrue(indexService.getIndexSettings().getSettings().hasValue("index.refresh_interval"));
         assertEquals("100", indexService.getIndexSettings().getSettings().get("index.mapping.depth.limit"));
 
         INDEX_SETTING_DEPTH_ENABLED.set(false);
-        INDEX_SETTING_PROVIDER2_ENABLED.set(true);
+        INDEX_SETTING_PROVIDER2_ENABLED.set(false);
+        INDEX_SETTING_PROVIDER3_ENABLED.set(true);
         var e = expectThrows(IllegalArgumentException.class, () -> createIndex("my-index4", settings));
         assertEquals(
             "additional index setting [index.refresh_interval] added by [TestIndexSettingsProvider] is already present",
@@ -49,39 +50,48 @@ public void testIndexCreation() throws Exception {
 
     @Override
     protected Collection<Class<? extends Plugin>> getPlugins() {
-        return List.of(Plugin1.class, Plugin2.class);
+        return List.of(Plugin1.class, Plugin2.class, Plugin3.class);
     }
 
     public static class Plugin1 extends Plugin {
 
         @Override
         public Collection<IndexSettingProvider> getAdditionalIndexSettingProviders(IndexSettingProvider.Parameters parameters) {
-            return List.of(new TestIndexSettingsProvider("-1", INDEX_SETTING_PROVIDER1_ENABLED));
+            return List.of(new TestIndexSettingsProvider("1s", INDEX_SETTING_PROVIDER1_ENABLED, false));
         }
-
     }
 
     public static class Plugin2 extends Plugin {
 
         @Override
         public Collection<IndexSettingProvider> getAdditionalIndexSettingProviders(IndexSettingProvider.Parameters parameters) {
-            return List.of(new TestIndexSettingsProvider("100s", INDEX_SETTING_PROVIDER2_ENABLED));
+            return List.of(new TestIndexSettingsProvider("1s", INDEX_SETTING_PROVIDER2_ENABLED, true));
+        }
+    }
+
+    public static class Plugin3 extends Plugin {
+
+        @Override
+        public Collection<IndexSettingProvider> getAdditionalIndexSettingProviders(IndexSettingProvider.Parameters parameters) {
+            return List.of(new TestIndexSettingsProvider("100s", INDEX_SETTING_PROVIDER3_ENABLED, false));
         }
     }
 
     private static final AtomicBoolean INDEX_SETTING_PROVIDER1_ENABLED = new AtomicBoolean(false);
     private static final AtomicBoolean INDEX_SETTING_PROVIDER2_ENABLED = new AtomicBoolean(false);
+    private static final AtomicBoolean INDEX_SETTING_PROVIDER3_ENABLED = new AtomicBoolean(false);
     private static final AtomicBoolean INDEX_SETTING_DEPTH_ENABLED = new AtomicBoolean(true);
-    private static final AtomicBoolean INDEX_SETTING_OVERRULING = new AtomicBoolean(false);
 
     static class TestIndexSettingsProvider implements IndexSettingProvider {
 
         private final String intervalValue;
         private final AtomicBoolean enabled;
+        private final boolean overruling;
 
-        TestIndexSettingsProvider(String intervalValue, AtomicBoolean enabled) {
+        TestIndexSettingsProvider(String intervalValue, AtomicBoolean enabled, boolean overruling) {
             this.intervalValue = intervalValue;
             this.enabled = enabled;
+            this.overruling = overruling;
         }
 
         @Override
@@ -91,13 +101,14 @@ public Settings getAdditionalIndexSettings(
             IndexMode templateIndexMode,
             Metadata metadata,
             Instant resolvedAt,
-            Settings indexTemplateAndCreateRequestSettings,
+            Settings incomingSettings,
             List<CompressedXContent> combinedTemplateMappings
         ) {
             if (enabled.get()) {
                 var builder = Settings.builder().put("index.refresh_interval", intervalValue);
                 if (INDEX_SETTING_DEPTH_ENABLED.get()) {
-                    builder.put("index.mapping.depth.limit", 100);
+                    // Verify that the value can be passed from non-overruling to overruling instance.
+                    builder.put("index.mapping.depth.limit", incomingSettings.hasValue("index.refresh_interval") ? 100 : 1);
                 }
                 return builder.build();
             } else {
@@ -106,8 +117,8 @@ public Settings getAdditionalIndexSettings(
         }
 
         @Override
-        public boolean overrulesTemplateAndRequestSettings() {
-            return INDEX_SETTING_OVERRULING.get();
+        public boolean overrulesSettings() {
+            return overruling;
         }
     }
 }

x-pack/plugin/logsdb/qa/with-basic/src/javaRestTest/java/org/elasticsearch/xpack/logsdb/LogsdbWithBasicRestIT.java

@@ -8,6 +8,7 @@
 package org.elasticsearch.xpack.logsdb;
 
 import org.elasticsearch.client.Request;
+import org.elasticsearch.cluster.metadata.DataStream;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.mapper.SourceFieldMapper;
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
@@ -171,4 +172,35 @@ public void testLogsdbOverrideNullInTemplate() throws IOException {
         assertEquals("logsdb", settings.get("index.mode"));
         assertEquals(SourceFieldMapper.Mode.STORED.toString(), settings.get("index.mapping.source.mode"));
     }
+
+    public void testLogsdbOverrideDefaultModeForLogsIndex() throws IOException {
+        Request request = new Request("PUT", "/_cluster/settings");
+        request.setJsonEntity("{ \"transient\": { \"cluster.logsdb.enabled\": true } }");
+        assertOK(client().performRequest(request));
+
+        request = new Request("POST", "/_index_template/1");
+        request.setJsonEntity("""
+            {
+                "index_patterns": ["logs-test-*"],
+                "data_stream": {
+                }
+            }
+            """);
+        assertOK(client().performRequest(request));
+
+        request = new Request("POST", "/logs-test-foo/_doc");
+        request.setJsonEntity("""
+            {
+                "@timestamp": "2020-01-01T00:00:00.000Z",
+                "host.name": "foo",
+                "message": "bar"
+            }
+            """);
+        assertOK(client().performRequest(request));
+
+        String index = DataStream.getDefaultBackingIndexName("logs-test-foo", 1);
+        var settings = (Map<?, ?>) ((Map<?, ?>) getIndexSettings(index).get(index)).get("settings");
+        assertEquals("logsdb", settings.get("index.mode"));
+        assertEquals(SourceFieldMapper.Mode.STORED.toString(), settings.get("index.mapping.source.mode"));
+    }
 }