Data stream settings API doesn't work for TSDS

[felixbarny]

Elasticsearch Version

9.2

Installed Plugins

No response

Java Version

bundled

OS Version

not relevant

Problem Description

When trying to use the data stream settings api on a time series data stream, it fails with the error message [index.mode=time_series] requires a non-empty [index.routing_path]

Steps to Reproduce

PUT _index_template/quickstart-tsds-template
{
  "index_patterns": ["quickstart-*"],
  "data_stream": { },
  "priority": 100, 
  "template": {
    "settings": {
      "index.mode": "time_series"
    },
    "mappings": {
      "properties": {
        "host.name": {
          "type": "keyword",
          "time_series_dimension": true
        }
      }
    }
  }
}


PUT _data_stream/quickstart-tsds
PUT _data_stream/quickstart-tsds/_settings
{
  "index.number_of_shards": 2
}

{
  "data_streams": [
    {
      "name": "quickstart-tsds",
      "applied_to_data_stream": false,
      "error": "[index.mode=time_series] requires a non-empty [index.routing_path]",
      "settings": {},
      "effective_settings": {},
      "index_settings_results": {
        "applied_to_data_stream_only": [],
        "applied_to_data_stream_and_write_indices": [],
        "applied_to_data_stream_and_backing_indices": []
      }
    }
  ]
}

Reproduce in tests:

---
Index: modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamSettingsIT.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamSettingsIT.java b/modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamSettingsIT.java
--- a/modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamSettingsIT.java	(revision 83120cd4a0e140b7ac3cdcd74beb5c2482614b3e)
+++ b/modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamSettingsIT.java	(date 1759913103316)
@@ -24,6 +24,7 @@
 import org.elasticsearch.cluster.metadata.ComposableIndexTemplate;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.cluster.metadata.Template;
+import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.core.Nullable;
@@ -154,6 +155,44 @@
         }
     }
 
+    public void testPutDataStreamSettingsTSDS() throws Exception {
+        String dataStreamName = randomAlphaOfLength(20).toLowerCase(Locale.ROOT);
+        putComposableIndexTemplate(
+            "my-template",
+            List.of(dataStreamName),
+            indexSettings(1, 0).put("index.mode", "time_series").build(),
+            CompressedXContent.fromJSON("""
+                {
+                  "properties": {
+                    "host.name": {
+                      "type": "keyword",
+                      "time_series_dimension": true
+                    }
+                  }
+                }
+                """)
+        );
+        final var createDataStreamRequest = new CreateDataStreamAction.Request(TEST_REQUEST_TIMEOUT, TEST_REQUEST_TIMEOUT, dataStreamName);
+        assertAcked(client().execute(CreateDataStreamAction.INSTANCE, createDataStreamRequest).actionGet());
+        final int numberOfShards = randomIntBetween(2, 7);
+        Settings dataStreamSettings = Settings.builder()
+            .put("index.number_of_shards", numberOfShards)
+            .build();
+        UpdateDataStreamSettingsAction.Response putSettingsResponse = client().execute(
+            UpdateDataStreamSettingsAction.INSTANCE,
+            new UpdateDataStreamSettingsAction.Request(dataStreamSettings, TimeValue.THIRTY_SECONDS, TimeValue.THIRTY_SECONDS).indices(
+                dataStreamName
+            )
+        ).actionGet();
+        List<UpdateDataStreamSettingsAction.DataStreamSettingsResponse> dataStreamSettingsResponses = putSettingsResponse
+            .getDataStreamSettingsResponses();
+        assertThat(dataStreamSettingsResponses.size(), equalTo(1));
+        UpdateDataStreamSettingsAction.DataStreamSettingsResponse dataStreamSettingsResponse = dataStreamSettingsResponses.get(0);
+        assertThat(dataStreamSettingsResponse.dataStreamName(), equalTo(dataStreamName));
+        assertThat(dataStreamSettingsResponse.dataStreamSucceeded(), equalTo(true));
+        assertThat(dataStreamSettingsResponse.settings().get("index.number_of_shards"), equalTo(Integer.toString(numberOfShards)));
+    }
+
     public void testPutMultipleDataStreamSettings() throws Exception {
         List<String> testDataStreamNames = new ArrayList<>();
         List<String> ignoredDataStreamNames = new ArrayList<>();
@@ -324,11 +363,20 @@
     }
 
     static void putComposableIndexTemplate(String id, List<String> patterns, @Nullable Settings settings) throws IOException {
+        putComposableIndexTemplate(id, patterns, settings, null);
+    }
+
+    static void putComposableIndexTemplate(
+        String id,
+        List<String> patterns,
+        @Nullable Settings settings,
+        @Nullable CompressedXContent mappings
+    ) throws IOException {
         TransportPutComposableIndexTemplateAction.Request request = new TransportPutComposableIndexTemplateAction.Request(id);
         request.indexTemplate(
             ComposableIndexTemplate.builder()
                 .indexPatterns(patterns)
-                .template(Template.builder().settings(settings))
+                .template(Template.builder().settings(settings).mappings(mappings))
                 .dataStreamTemplate(new ComposableIndexTemplate.DataStreamTemplate())
                 .build()
         );
Index: x-pack/plugin/otel-data/src/yamlRestTest/resources/rest-api-spec/test/20_metrics_tests.yml
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/x-pack/plugin/otel-data/src/yamlRestTest/resources/rest-api-spec/test/20_metrics_tests.yml b/x-pack/plugin/otel-data/src/yamlRestTest/resources/rest-api-spec/test/20_metrics_tests.yml
--- a/x-pack/plugin/otel-data/src/yamlRestTest/resources/rest-api-spec/test/20_metrics_tests.yml	(revision 83120cd4a0e140b7ac3cdcd74beb5c2482614b3e)
+++ b/x-pack/plugin/otel-data/src/yamlRestTest/resources/rest-api-spec/test/20_metrics_tests.yml	(date 1759911177211)
@@ -351,3 +351,28 @@
   - length: { hits.hits: 1 }
   - match: { hits.hits.0.fields.resource\.attributes\.host\.name: [ "localhost" ] }
   - match: { hits.hits.0.fields.host\.name: [ "localhost" ] }
+
+---
+data stream settings ilm:
+  - do:
+      bulk:
+        index: metrics-generic.otel-default
+        refresh: true
+        body:
+          - create: {"dynamic_templates":{"metrics.foo.bar":"counter_long"}}
+          - "@timestamp": 2024-07-18T14:00:00Z
+            resource:
+              attributes:
+                host.name: localhost
+            metrics:
+              foo.bar: 42
+  - is_false: errors
+  - do:
+      indices.put_data_stream_settings:
+        name: metrics-generic.otel-default
+        body:
+          index:
+            number_of_shards: 2
+  - match: { data_streams.0.name: metrics-generic.otel-default }
+  - match: { data_streams.0.applied_to_data_stream: true }
+

Logs (if relevant)

No response

[elasticsearchmachine]

Pinging @elastic/es-data-management (Team:Data Management)

[felixbarny]

I think the issue is that we're not invoking the IndexSettingProviders (in particular the DataStreamIndexSettingProvider) when validating the settings when invoking the data stream settings API.