Adding dry_run mode for setting data stream settings

modules/data-streams/src/main/java/org/elasticsearch/datastreams/action/TransportUpdateDataStreamSettingsAction.java

@@ -123,6 +123,7 @@ public void onFailure(Exception e) {
             updateSingleDataStream(
                 dataStreamName,
                 request.getSettings(),
+                request.isDryRun(),
                 request.masterNodeTimeout(),
                 request.ackTimeout(),
                 new ActionListener<>() {
@@ -154,6 +155,7 @@ public void onFailure(Exception e) {
     private void updateSingleDataStream(
         String dataStreamName,
         Settings settingsOverrides,
+        boolean dryRun,
         TimeValue masterNodeTimeout,
         TimeValue ackTimeout,
         ActionListener<UpdateDataStreamSettingsAction.DataStreamSettingsResponse> listener
@@ -198,11 +200,12 @@ private void updateSingleDataStream(
             ackTimeout,
             dataStreamName,
             settingsOverrides,
+            dryRun,
             new ActionListener<>() {
                 @Override
-                public void onResponse(AcknowledgedResponse acknowledgedResponse) {
-                    if (acknowledgedResponse.isAcknowledged()) {
-                        updateSettingsOnIndices(dataStreamName, settingsOverrides, masterNodeTimeout, ackTimeout, listener);
+                public void onResponse(DataStream dataStream) {
+                    if (dataStream != null) {
+                        updateSettingsOnIndices(dataStream, settingsOverrides, dryRun, masterNodeTimeout, ackTimeout, listener);
                     } else {
                         listener.onResponse(
                             new UpdateDataStreamSettingsAction.DataStreamSettingsResponse(
@@ -226,8 +229,9 @@ public void onFailure(Exception e) {
     }
 
     private void updateSettingsOnIndices(
-        String dataStreamName,
+        DataStream dataStream,
         Settings requestSettings,
+        boolean dryRun,
         TimeValue masterNodeTimeout,
         TimeValue ackTimeout,
         ActionListener<UpdateDataStreamSettingsAction.DataStreamSettingsResponse> listener
@@ -243,26 +247,16 @@ private void updateSettingsOnIndices(
                 appliedToDataStreamOnly.add(settingName);
             }
         }
-        final List<Index> concreteIndices = clusterService.state()
-            .projectState(projectResolver.getProjectId())
-            .metadata()
-            .dataStreams()
-            .get(dataStreamName)
-            .getIndices();
+        final List<Index> concreteIndices = dataStream.getIndices();
         final List<UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError> indexSettingErrors = new ArrayList<>();
 
         CountDownActionListener indexCountDownListener = new CountDownActionListener(concreteIndices.size() + 1, new ActionListener<>() {
             // Called when all indices for all settings are complete
             @Override
             public void onResponse(Void unused) {
-                DataStream dataStream = clusterService.state()
-                    .projectState(projectResolver.getProjectId())
-                    .metadata()
-                    .dataStreams()
-                    .get(dataStreamName);
                 listener.onResponse(
                     new UpdateDataStreamSettingsAction.DataStreamSettingsResponse(
-                        dataStreamName,
+                        dataStream.getName(),
                         true,
                         null,
                         settingsFilter.filter(dataStream.getSettings()),
@@ -286,7 +280,7 @@ public void onFailure(Exception e) {
         indexCountDownListener.onResponse(null); // handles the case where there were zero indices
         Settings applyToIndexSettings = builder().loadFromMap(settingsToApply).build();
         for (Index index : concreteIndices) {
-            updateSettingsOnSingleIndex(index, applyToIndexSettings, masterNodeTimeout, ackTimeout, new ActionListener<>() {
+            updateSettingsOnSingleIndex(index, applyToIndexSettings, dryRun, masterNodeTimeout, ackTimeout, new ActionListener<>() {
                 @Override
                 public void onResponse(UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError indexSettingError) {
                     if (indexSettingError != null) {
@@ -306,6 +300,7 @@ public void onFailure(Exception e) {
     private void updateSettingsOnSingleIndex(
         Index index,
         Settings requestSettings,
+        boolean dryRun,
         TimeValue masterNodeTimeout,
         TimeValue ackTimeout,
         ActionListener<UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError> listener
@@ -326,39 +321,50 @@ private void updateSettingsOnSingleIndex(
                 );
                 return;
             }
-            updateSettingsService.updateSettings(
-                new UpdateSettingsClusterStateUpdateRequest(
-                    projectResolver.getProjectId(),
-                    masterNodeTimeout,
-                    ackTimeout,
-                    requestSettings,
-                    UpdateSettingsClusterStateUpdateRequest.OnExisting.OVERWRITE,
-                    UpdateSettingsClusterStateUpdateRequest.OnStaticSetting.REOPEN_INDICES,
-                    index
-                ),
-                new ActionListener<>() {
-                    @Override
-                    public void onResponse(AcknowledgedResponse response) {
-                        UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError error;
-                        if (response.isAcknowledged() == false) {
-                            error = new UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError(
-                                index.getName(),
-                                "Updating settings not acknowledged for unknown reason"
-                            );
-                        } else {
-                            error = null;
+            if (dryRun) {
+                /*
+                 * This is as far as we go with dry run mode. We get the benefit of having checked that all the indices that will be touced
+                 * are not blocked, but there is no value in going behond this. So just respond to the listener and move on.
+                 */
+                listener.onResponse(null);
+            } else {
+                updateSettingsService.updateSettings(
+                    new UpdateSettingsClusterStateUpdateRequest(
+                        projectResolver.getProjectId(),
+                        masterNodeTimeout,
+                        ackTimeout,
+                        requestSettings,
+                        UpdateSettingsClusterStateUpdateRequest.OnExisting.OVERWRITE,
+                        UpdateSettingsClusterStateUpdateRequest.OnStaticSetting.REOPEN_INDICES,
+                        index
+                    ),
+                    new ActionListener<>() {
+                        @Override
+                        public void onResponse(AcknowledgedResponse response) {
+                            UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError error;
+                            if (response.isAcknowledged() == false) {
+                                error = new UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError(
+                                    index.getName(),
+                                    "Updating settings not acknowledged for unknown reason"
+                                );
+                            } else {
+                                error = null;
+                            }
+                            listener.onResponse(error);
                         }
-                        listener.onResponse(error);
-                    }
 
-                    @Override
-                    public void onFailure(Exception e) {
-                        listener.onResponse(
-                            new UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError(index.getName(), e.getMessage())
-                        );
+                        @Override
+                        public void onFailure(Exception e) {
+                            listener.onResponse(
+                                new UpdateDataStreamSettingsAction.DataStreamSettingsResponse.IndexSettingError(
+                                    index.getName(),
+                                    e.getMessage()
+                                )
+                            );
+                        }
                     }
-                }
-            );
+                );
+            }
         }
 
     }

modules/data-streams/src/main/java/org/elasticsearch/datastreams/rest/RestUpdateDataStreamSettingsAction.java

@@ -45,8 +45,10 @@ protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient cli
         try (XContentParser parser = request.contentParser()) {
             settings = Settings.fromXContent(parser);
         }
+        boolean dryRun = request.paramAsBoolean("dry_run", false);
         UpdateDataStreamSettingsAction.Request putDataStreamRequest = new UpdateDataStreamSettingsAction.Request(
             settings,
+            dryRun,
             RestUtils.getMasterNodeTimeout(request),
             RestUtils.getAckTimeout(request)
         ).indices(Strings.splitStringByCommaToArray(request.param("name")));

modules/data-streams/src/yamlRestTest/resources/rest-api-spec/test/data_stream/240_data_stream_settings.yml

@@ -192,3 +192,103 @@ setup:
   - match: { data_streams.0.name: my-data-stream-1 }
   - match: { data_streams.0.applied_to_data_stream: false }
   - match: { data_streams.0.error: "Cannot set the following settings on a data stream: [index.fake_setting]" }
+
+---
+"Test dry run":
+  - requires:
+      cluster_features: [ "logs_stream" ]
+      reason: requires setting 'logs_stream' to get or set data stream settings
+  - do:
+      allowed_warnings:
+        - "index template [my-template] has index patterns [my-data-stream-*] matching patterns from existing older templates [global] with patterns (global => [*]); this template [my-template] will take precedence during new index creation"
+      indices.put_index_template:
+        name: my-template
+        body:
+          index_patterns: [ my-data-stream-* ]
+          data_stream: { }
+          template:
+            settings:
+              number_of_replicas: 0
+              lifecycle.name: my-policy
+
+  - do:
+      indices.create_data_stream:
+        name: my-data-stream-1
+
+  - do:
+      cluster.health:
+        index: "my-data-stream-1"
+        wait_for_status: green
+
+  - do:
+      indices.get_data_stream_settings:
+        name: my-data-stream-1
+  - match: { data_streams.0.name: my-data-stream-1 }
+  - match: { data_streams.0.settings: {} }
+  - match: { data_streams.0.effective_settings.index.number_of_shards: null }
+  - match: { data_streams.0.effective_settings.index.number_of_replicas: "0" }
+  - match: { data_streams.0.effective_settings.index.lifecycle.name: "my-policy" }
+
+  - do:
+      indices.get_data_stream:
+        name: my-data-stream-1
+  - match: { data_streams.0.name: my-data-stream-1 }
+  - match: { data_streams.0.settings: {} }
+  - match: { data_streams.0.effective_settings: null }
+
+  - do:
+      indices.put_data_stream_settings:
+        name: my-data-stream-1
+        dry_run: true
+        body:
+          index:
+            number_of_shards: 2
+            lifecycle.name: my-new-policy
+  - match: { data_streams.0.name: my-data-stream-1 }
+  - match: { data_streams.0.applied_to_data_stream: true }
+  - match: { data_streams.0.index_settings_results.applied_to_data_stream_only: [index.number_of_shards]}
+  - match: { data_streams.0.index_settings_results.applied_to_data_stream_and_backing_indices: [index.lifecycle.name] }
+  - match: { data_streams.0.settings.index.number_of_shards: "2" }
+  - match: { data_streams.0.settings.index.lifecycle.name: "my-new-policy" }
+  - match: { data_streams.0.effective_settings.index.number_of_shards: "2" }
+  - match: { data_streams.0.effective_settings.index.number_of_replicas: "0" }
+  - match: { data_streams.0.effective_settings.index.lifecycle.name: "my-new-policy" }
+
+  - do:
+      indices.rollover:
+        alias: "my-data-stream-1"
+
+  - do:
+      cluster.health:
+        index: "my-data-stream-1"
+        wait_for_status: green
+
+  - do:
+      indices.get_data_stream_settings:
+        name: my-data-stream-1
+  - match: { data_streams.0.name: my-data-stream-1 }
+  - match: { data_streams.0.settings: {} }
+  - match: { data_streams.0.effective_settings.index.number_of_shards: null }
+  - match: { data_streams.0.effective_settings.index.number_of_replicas: "0" }
+  - match: { data_streams.0.effective_settings.index.lifecycle.name: "my-policy" }
+
+  - do:
+      indices.get_data_stream:
+        name: my-data-stream-1
+  - match: { data_streams.0.name: my-data-stream-1 }
+  - match: { data_streams.0.settings: {} }
+  - match: { data_streams.0.effective_settings: null }
+
+  - do:
+      indices.get_data_stream:
+        name: my-data-stream-1
+  - set: { data_streams.0.indices.0.index_name: idx0name }
+  - set: { data_streams.0.indices.1.index_name: idx1name }
+
+  - do:
+      indices.get_settings:
+        index: my-data-stream-1
+  - match: { .$idx0name.settings.index.number_of_shards: "1" }
+  - match: { .$idx0name.settings.index.lifecycle.name: "my-policy" }
+  - match: { .$idx1name.settings.index.number_of_shards: "1" }
+  - match: { .$idx1name.settings.index.lifecycle.name: "my-policy" }

rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_data_stream_settings.json

@@ -27,6 +27,11 @@
       ]
     },
     "params":{
+      "dry_run":{
+        "type":"boolean",
+        "description":"Perform a dry run but do not actually change any settings",
+        "default":false
+      },
       "timeout":{
         "type":"time",
         "description":"Specify timeout for acknowledging the cluster state update"

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -261,6 +261,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion ESQL_HASH_OPERATOR_STATUS_OUTPUT_TIME = def(9_077_0_00);
     public static final TransportVersion ML_INFERENCE_HUGGING_FACE_CHAT_COMPLETION_ADDED = def(9_078_0_00);
     public static final TransportVersion NODES_STATS_SUPPORTS_MULTI_PROJECT = def(9_079_0_00);
+    public static final TransportVersion SETTINGS_IN_DATA_STREAMS_DRY_RUN = def(9_080_0_00);
 
     /*
      * STOP! READ THIS FIRST! No, really,

server/src/main/java/org/elasticsearch/action/datastreams/UpdateDataStreamSettingsAction.java

@@ -9,6 +9,7 @@
 
 package org.elasticsearch.action.datastreams;
 
+import org.elasticsearch.TransportVersions;
 import org.elasticsearch.action.ActionResponse;
 import org.elasticsearch.action.ActionType;
 import org.elasticsearch.action.IndicesRequest;
@@ -47,10 +48,16 @@ public UpdateDataStreamSettingsAction() {
     public static class Request extends AcknowledgedRequest<Request> implements IndicesRequest.Replaceable {
         private final Settings settings;
         private String[] dataStreamNames = Strings.EMPTY_ARRAY;
+        private final boolean dryRun;
 
         public Request(Settings settings, TimeValue masterNodeTimeout, TimeValue ackTimeout) {
+            this(settings, false, masterNodeTimeout, ackTimeout);
+        }
+
+        public Request(Settings settings, boolean dryRun, TimeValue masterNodeTimeout, TimeValue ackTimeout) {
             super(masterNodeTimeout, ackTimeout);
             this.settings = settings;
+            this.dryRun = dryRun;
         }
 
         @Override
@@ -63,6 +70,10 @@ public Settings getSettings() {
             return settings;
         }
 
+        public boolean isDryRun() {
+            return dryRun;
+        }
+
         @Override
         public boolean includeDataStreams() {
             return true;
@@ -72,13 +83,21 @@ public Request(StreamInput in) throws IOException {
             super(in);
             this.dataStreamNames = in.readStringArray();
             this.settings = Settings.readSettingsFromStream(in);
+            if (in.getTransportVersion().onOrAfter(TransportVersions.SETTINGS_IN_DATA_STREAMS)) {
+                this.dryRun = in.readBoolean();
+            } else {
+                this.dryRun = false;
+            }
         }
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
             super.writeTo(out);
             out.writeStringArray(dataStreamNames);
             settings.writeTo(out);
+            if (out.getTransportVersion().onOrAfter(TransportVersions.SETTINGS_IN_DATA_STREAMS_DRY_RUN)) {
+                out.writeBoolean(dryRun);
+            }
         }
 
         @Override
@@ -103,13 +122,14 @@ public boolean equals(Object o) {
             Request request = (Request) o;
             return Arrays.equals(dataStreamNames, request.dataStreamNames)
                 && settings.equals(request.settings)
+                && dryRun == request.dryRun
                 && Objects.equals(masterNodeTimeout(), request.masterNodeTimeout())
                 && Objects.equals(ackTimeout(), request.ackTimeout());
         }
 
         @Override
         public int hashCode() {
-            return Objects.hash(Arrays.hashCode(dataStreamNames), settings, masterNodeTimeout(), ackTimeout());
+            return Objects.hash(Arrays.hashCode(dataStreamNames), settings, dryRun, masterNodeTimeout(), ackTimeout());
         }
 
     }