Adding params for enabling and disabling mapping_stats and analysis_s…

server/src/internalClusterTest/java/org/opensearch/action/admin/cluster/stats/ClusterStatsIT.java

@@ -288,7 +288,12 @@ public void testClusterStatusWhenStateNotRecovered() throws Exception {
     public void testFieldTypes() {
         internalCluster().startNode();
         ensureGreen();
-        ClusterStatsResponse response = client().admin().cluster().prepareClusterStats().get();
+        ClusterStatsResponse response = client().admin()
+            .cluster()
+            .prepareClusterStats()
+            .includeAnalysisStats(true)
+            .includeMappingStats(true)
+            .get();
         assertThat(response.getStatus(), Matchers.equalTo(ClusterHealthStatus.GREEN));
         assertTrue(response.getIndicesStats().getMappings().getFieldTypeStats().isEmpty());
 
@@ -301,7 +306,7 @@ public void testFieldTypes() {
                     + "\"eggplant\":{\"type\":\"integer\"}}}}}"
             )
             .get();
-        response = client().admin().cluster().prepareClusterStats().get();
+        response = client().admin().cluster().prepareClusterStats().includeMappingStats(true).includeAnalysisStats(true).get();
         assertThat(response.getIndicesStats().getMappings().getFieldTypeStats().size(), equalTo(3));
         Set<IndexFeatureStats> stats = response.getIndicesStats().getMappings().getFieldTypeStats();
         for (IndexFeatureStats stat : stats) {

server/src/main/java/org/opensearch/action/ActionModule.java

@@ -808,7 +808,7 @@ public void initRestHandlers(Supplier<DiscoveryNodes> nodesInCluster) {
         registerHandler.accept(new RestNodesUsageAction());
         registerHandler.accept(new RestNodesHotThreadsAction());
         registerHandler.accept(new RestClusterAllocationExplainAction());
-        registerHandler.accept(new RestClusterStatsAction());
+        registerHandler.accept(new RestClusterStatsAction(settings, clusterSettings));
         registerHandler.accept(new RestClusterStateAction(settingsFilter));
         registerHandler.accept(new RestClusterHealthAction());
         registerHandler.accept(new RestClusterUpdateSettingsAction());

server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequest.java

@@ -47,10 +47,29 @@
 @PublicApi(since = "1.0.0")
 public class ClusterStatsRequest extends BaseNodesRequest<ClusterStatsRequest> {
 
+    private boolean includeMappingStats;
+    private boolean includeAnalysisStats;
+
     public ClusterStatsRequest(StreamInput in) throws IOException {
         super(in);
     }
 
+    public void setIncludeMappingStats(boolean bool) {
+        this.includeMappingStats = bool;
+    }
+
+    public boolean isIncludeMappingStats() {
+        return includeMappingStats;
+    }
+
+    public void setIncludeAnalysisStats(boolean bool) {
+        this.includeAnalysisStats = bool;
+    }
+
+    public boolean isIncludeAnalysisStats() {
+        return includeAnalysisStats;
+    }
+
     /**
      * Get stats from nodes based on the nodes ids specified. If none are passed, stats
      * based on all nodes will be returned.

server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsRequestBuilder.java

@@ -50,4 +50,14 @@ public class ClusterStatsRequestBuilder extends NodesOperationRequestBuilder<
     public ClusterStatsRequestBuilder(OpenSearchClient client, ClusterStatsAction action) {
         super(client, action, new ClusterStatsRequest());
     }
+
+    public ClusterStatsRequestBuilder includeMappingStats(boolean value) {
+        request.setIncludeMappingStats(value);
+        return this;
+    }
+
+    public ClusterStatsRequestBuilder includeAnalysisStats(boolean value) {
+        request.setIncludeAnalysisStats(value);
+        return this;
+    }
 }

server/src/main/java/org/opensearch/action/admin/cluster/stats/ClusterStatsResponse.java

@@ -105,6 +105,35 @@ public ClusterStatsResponse(
         this.status = status;
     }
 
+    public ClusterStatsResponse(
+        long timestamp,
+        String clusterUUID,
+        ClusterName clusterName,
+        List<ClusterStatsNodeResponse> nodes,
+        List<FailedNodeException> failures,
+        ClusterState state,
+        ClusterStatsRequest request
+    ) {
+        super(clusterName, nodes, failures);
+        this.clusterUUID = clusterUUID;
+        this.timestamp = timestamp;
+        nodesStats = new ClusterStatsNodes(nodes);
+        indicesStats = new ClusterStatsIndices(
+            nodes,
+            request.isIncludeMappingStats() ? MappingStats.of(state) : null,
+            request.isIncludeAnalysisStats() ? AnalysisStats.of(state) : null
+        );
+        ClusterHealthStatus status = null;
+        for (ClusterStatsNodeResponse response : nodes) {
+            // only the cluster-manager node populates the status
+            if (response.clusterStatus() != null) {
+                status = response.clusterStatus();
+                break;
+            }
+        }
+        this.status = status;
+    }
+
     public String getClusterUUID() {
         return this.clusterUUID;
     }

server/src/main/java/org/opensearch/action/admin/cluster/stats/TransportClusterStatsAction.java

@@ -129,7 +129,8 @@ protected ClusterStatsResponse newResponse(
             clusterService.getClusterName(),
             responses,
             failures,
-            state
+            state,
+            request
         );
     }
 

server/src/main/java/org/opensearch/common/settings/ClusterSettings.java

@@ -149,6 +149,7 @@
 import org.opensearch.ratelimitting.admissioncontrol.settings.IoBasedAdmissionControllerSettings;
 import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.action.admin.cluster.RestClusterStatsAction;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.SearchModule;
 import org.opensearch.search.SearchService;
@@ -749,7 +750,9 @@ public void apply(Settings value, Settings current, Settings previous) {
                 RemoteStoreSettings.CLUSTER_REMOTE_STORE_PATH_HASH_ALGORITHM_SETTING,
                 RemoteStoreSettings.CLUSTER_REMOTE_MAX_TRANSLOG_READERS,
                 RemoteStoreSettings.CLUSTER_REMOTE_STORE_TRANSLOG_METADATA,
-                SearchService.CLUSTER_ALLOW_DERIVED_FIELD_SETTING
+                SearchService.CLUSTER_ALLOW_DERIVED_FIELD_SETTING,
+
+                RestClusterStatsAction.CLUSTER_STATS_LEVEL_SETTING
             )
         )
     );

server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStatsAction.java

@@ -34,6 +34,9 @@
 
 import org.opensearch.action.admin.cluster.stats.ClusterStatsRequest;
 import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.Setting;
+import org.opensearch.common.settings.Settings;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.RestRequest;
 import org.opensearch.rest.action.RestActions.NodesResponseRestListener;
@@ -52,6 +55,40 @@
  */
 public class RestClusterStatsAction extends BaseRestHandler {
 
+    /**
+     * Setting up the response in the form of levels - for experimental testings -
+     *          level 1 excludes Mapping and Analysis Stats.
+     *
+     * This will determine the default behavior of the cluster stats call.
+     */
+    public static final String CLUSTER_STATS_RESPONSE_LEVEL = "opensearch.experimental.optimization.cluster_stats.response_level";
+
+    public static final Setting<Integer> CLUSTER_STATS_LEVEL_SETTING = Setting.intSetting(
+        CLUSTER_STATS_RESPONSE_LEVEL,
+        2,
+        1,
+        Setting.Property.NodeScope,
+        Setting.Property.Dynamic
+    );
+
+    public volatile boolean defaultMappingAndAnalysisStats;
+
+    public RestClusterStatsAction(Settings settings, ClusterSettings clusterSettings) {
+        updateMappingAndAnalysisStatsFromLevel(CLUSTER_STATS_LEVEL_SETTING.get(settings));
+        clusterSettings.addSettingsUpdateConsumer(CLUSTER_STATS_LEVEL_SETTING, this::updateMappingAndAnalysisStatsFromLevel);
+    }
+
+    private void updateMappingAndAnalysisStatsFromLevel(int level) {
+        switch (level) {
+            case 1:
+                this.defaultMappingAndAnalysisStats = false;
+                break;
+            case 2:
+                this.defaultMappingAndAnalysisStats = true;
+                break;
+        }
+    }
+
     @Override
     public List<Route> routes() {
         return unmodifiableList(asList(new Route(GET, "/_cluster/stats"), new Route(GET, "/_cluster/stats/nodes/{nodeId}")));
@@ -66,6 +103,10 @@ public String getName() {
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         ClusterStatsRequest clusterStatsRequest = new ClusterStatsRequest().nodesIds(request.paramAsStringArray("nodeId", null));
         clusterStatsRequest.timeout(request.param("timeout"));
+
+        clusterStatsRequest.setIncludeMappingStats(request.paramAsBoolean("include_mapping_stats", defaultMappingAndAnalysisStats));
+        clusterStatsRequest.setIncludeAnalysisStats(request.paramAsBoolean("include_analysis_stats", defaultMappingAndAnalysisStats));
+
         return channel -> client.admin().cluster().clusterStats(clusterStatsRequest, new NodesResponseRestListener<>(channel));
     }