Apply settings filter to get cluster settings API

server/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestClusterGetSettingsAction.java

@@ -87,13 +87,19 @@ public boolean canTripCircuitBreaker() {
 
     private XContentBuilder renderResponse(ClusterState state, boolean renderDefaults, XContentBuilder builder, ToXContent.Params params)
             throws IOException {
-        return
-            new ClusterGetSettingsResponse(
-                state.metaData().persistentSettings(),
-                state.metaData().transientSettings(),
-                renderDefaults ?
-                    settingsFilter.filter(clusterSettings.diff(state.metaData().settings(), this.settings)) :
-                    Settings.EMPTY
-            ).toXContent(builder, params);
+        return response(state, renderDefaults, settingsFilter, clusterSettings, settings).toXContent(builder, params);
     }
+
+    static ClusterGetSettingsResponse response(
+            final ClusterState state,
+            final boolean renderDefaults,
+            final SettingsFilter settingsFilter,
+            final ClusterSettings clusterSettings,
+            final Settings settings) {
+        return new ClusterGetSettingsResponse(
+                settingsFilter.filter(state.metaData().persistentSettings()),
+                settingsFilter.filter(state.metaData().transientSettings()),
+                renderDefaults ? settingsFilter.filter(clusterSettings.diff(state.metaData().settings(), settings)) : Settings.EMPTY);
+    }
+
 }

server/src/test/java/org/elasticsearch/rest/action/admin/cluster/RestClusterGetSettingsActionTests.java

@@ -0,0 +1,70 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.rest.action.admin.cluster;
+
+import org.elasticsearch.action.admin.cluster.settings.ClusterGetSettingsResponse;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.metadata.MetaData;
+import org.elasticsearch.common.settings.ClusterSettings;
+import org.elasticsearch.common.settings.Setting;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.settings.SettingsFilter;
+import org.elasticsearch.test.ESTestCase;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+
+public class RestClusterGetSettingsActionTests extends ESTestCase {
+
+    public void testFilterPersistentSettings() {
+        runTestFilterSettingsTest(MetaData.Builder::persistentSettings, ClusterGetSettingsResponse::getPersistentSettings);
+    }
+
+    public void testFilterTransientSettings() {
+        runTestFilterSettingsTest(MetaData.Builder::transientSettings, ClusterGetSettingsResponse::getTransientSettings);
+    }
+
+    private void runTestFilterSettingsTest(
+            final BiConsumer<MetaData.Builder, Settings> md, final Function<ClusterGetSettingsResponse, Settings> s) {
+        final MetaData.Builder mdBuilder = new MetaData.Builder();
+        final Settings settings = Settings.builder().put("foo.filtered", "bar").put("foo.non_filtered", "baz").build();
+        md.accept(mdBuilder, settings);
+        final ClusterState.Builder builder = new ClusterState.Builder(ClusterState.EMPTY_STATE).metaData(mdBuilder);
+        final SettingsFilter filter = new SettingsFilter(Settings.EMPTY, Collections.singleton("foo.filtered"));
+        final Setting.Property[] properties = {Setting.Property.Dynamic, Setting.Property.Filtered, Setting.Property.NodeScope};
+        final Set<Setting<?>> settingsSet = Stream.concat(
+                ClusterSettings.BUILT_IN_CLUSTER_SETTINGS.stream(),
+                Stream.concat(
+                        Stream.of(Setting.simpleString("foo.filtered", properties)),
+                        Stream.of(Setting.simpleString("foo.non_filtered", properties))))
+                .collect(Collectors.toSet());
+        final ClusterSettings clusterSettings = new ClusterSettings(Settings.EMPTY, settingsSet);
+        final ClusterGetSettingsResponse response =
+                RestClusterGetSettingsAction.response(builder.build(), randomBoolean(), filter, clusterSettings, Settings.EMPTY);
+        assertFalse(s.apply(response).hasValue("foo.filtered"));
+        assertTrue(s.apply(response).hasValue("foo.non_filtered"));
+    }
+
+}