Configure returnLocalAll on FieldCapabilitiesRequest (#134284)

Author: idegtiarenko

server/src/internalClusterTest/java/org/elasticsearch/search/fieldcaps/CCSFieldCapabilitiesIT.java

@@ -27,9 +27,12 @@
 import static org.hamcrest.Matchers.arrayContaining;
 import static org.hamcrest.Matchers.arrayContainingInAnyOrder;
 import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.emptyArray;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasItems;
 import static org.hamcrest.Matchers.hasKey;
 import static org.hamcrest.Matchers.hasSize;
+import static org.hamcrest.Matchers.not;
 
 public class CCSFieldCapabilitiesIT extends AbstractMultiClustersTestCase {
 
@@ -162,7 +165,6 @@ public void testIncludeIndices() {
         // mapping conflict, therefore indices is always present for `field3`
         assertThat(response.getField("field3").get("long").indices(), arrayContaining(remoteIndex));
         assertThat(response.getField("field3").get("keyword").indices(), arrayContaining(localIndex));
-
     }
 
     public void testRandomIncludeIndices() {
@@ -241,4 +243,27 @@ public void testIncludeIndicesSwapped() {
         assertThat(response.getField("field3").get("long").indices(), arrayContaining(localIndex));
         assertThat(response.getField("field3").get("keyword").indices(), arrayContaining(remoteIndex));
     }
+
+    public void testReturnAllLocal() {
+        assertAcked(
+            client().admin()
+                .indices()
+                .prepareCreate("index")
+                .setMapping("@timestamp", "type=date", "field1", "type=keyword", "field2", "type=long")
+        );
+        for (var pattern : List.of("fake-remote*:index", "fake-remote*:*")) {
+            {
+                // returnLocalAll = true by default
+                var response = client().prepareFieldCaps(pattern).setFields("*").get();
+                assertThat(response.getIndices(), arrayContaining("index"));
+                assertThat(response.get().keySet(), hasItems("@timestamp", "field1", "field2"));
+            }
+            {
+                // user can opt out by explicitly setting returnLocalAll=false
+                var response = client().prepareFieldCaps(pattern).setFields("*").setReturnLocalAll(false).get();
+                assertThat(response.getIndices(), emptyArray());
+                assertThat(response.get().keySet(), not(hasItems("@timestamp", "field1", "field2")));
+            }
+        }
+    }
 }

server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesRequest.java

@@ -54,6 +54,14 @@ public final class FieldCapabilitiesRequest extends LegacyActionRequest implemen
      * in the response if required.
      */
     private transient boolean includeIndices = false;
+
+    /**
+     * Controls whether all local indices should be returned if no remotes matched
+     * See {@link org.elasticsearch.transport.RemoteClusterService#groupIndices} returnLocalAll argument.
+     * This flag is only used locally on the coordinating node for index grouping and does not need to be serialized.
+     */
+    private transient boolean returnLocalAll = true;
+
     // pkg private API mainly for cross cluster search to signal that we do multiple reductions ie. the results should not be merged
     private boolean mergeResults = true;
     private QueryBuilder indexFilter;
@@ -214,6 +222,11 @@ public FieldCapabilitiesRequest includeIndices(boolean includeIndices) {
         return this;
     }
 
+    public FieldCapabilitiesRequest returnLocalAll(boolean returnLocalAll) {
+        this.returnLocalAll = returnLocalAll;
+        return this;
+    }
+
     @Override
     public String[] indices() {
         return indices;
@@ -242,6 +255,10 @@ public boolean includeIndices() {
         return includeIndices;
     }
 
+    public boolean returnLocalAll() {
+        return returnLocalAll;
+    }
+
     public boolean includeEmptyFields() {
         return includeEmptyFields;
     }

server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesRequestBuilder.java

@@ -58,4 +58,9 @@ public FieldCapabilitiesRequestBuilder setIncludeIndices(boolean includeIndices)
         request().includeIndices(includeIndices);
         return this;
     }
+
+    public FieldCapabilitiesRequestBuilder setReturnLocalAll(boolean returnLocalAll) {
+        request().returnLocalAll(returnLocalAll);
+        return this;
+    }
 }

server/src/main/java/org/elasticsearch/action/fieldcaps/TransportFieldCapabilitiesAction.java

@@ -169,7 +169,7 @@ private void doExecuteForked(
         long nowInMillis = request.nowInMillis() == null ? System.currentTimeMillis() : request.nowInMillis();
         final ProjectState projectState = projectResolver.getProjectState(clusterService.state());
         final Map<String, OriginalIndices> remoteClusterIndices = transportService.getRemoteClusterService()
-            .groupIndices(request.indicesOptions(), request.indices());
+            .groupIndices(request.indicesOptions(), request.indices(), request.returnLocalAll());
         final OriginalIndices localIndices = remoteClusterIndices.remove(RemoteClusterAware.LOCAL_CLUSTER_GROUP_KEY);
         final String[] concreteIndices;
         if (localIndices == null) {