[Feature/extensions] Adding support to register settings dynamically

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

@@ -121,8 +121,8 @@ protected AbstractScopedSettings(
  keySettings.putIfAbsent(setting.getKey(), setting);
  }
  }
- this.complexMatchers = Collections.unmodifiableMap(complexMatchers);
- this.keySettings = Collections.unmodifiableMap(keySettings);
+ this.complexMatchers = complexMatchers;
+ this.keySettings = keySettings;
  }
 
  protected void validateSettingKey(Setting<?> setting) {
@@ -144,6 +144,15 @@ protected AbstractScopedSettings(Settings nodeSettings, Settings scopeSettings,
  settingUpdaters.addAll(other.settingUpdaters);
  }
 
+ protected boolean registerSetting(Setting<?> setting) {
+ validateSettingKey(setting);
+ if (setting.hasComplexMatcher()) {
+ return setting != complexMatchers.putIfAbsent(setting.getKey(), setting);
+ } else {
+ return setting != keySettings.putIfAbsent(setting.getKey(), setting);
+ }
+ }
+
  /**
  * Returns <code>true</code> iff the given key is a valid settings key otherwise <code>false</code>
  */

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

@@ -162,6 +162,10 @@ public ClusterSettings(final Settings nodeSettings, final Set<Setting<?>> settin
  addSettingsUpdater(new LoggingSettingUpdater(nodeSettings));
  }
 
+ public boolean registerSetting(Setting<?> setting) {
+ return super.registerSetting(setting);
+ }
+
  private static final class LoggingSettingUpdater implements SettingUpdater<Settings> {
  final Predicate<String> loggerPredicate = Loggers.LOG_LEVEL_SETTING::match;
  private final Settings settings;

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

@@ -236,6 +236,11 @@ public IndexScopedSettings copy(Settings settings, IndexMetadata metadata) {
  return new IndexScopedSettings(settings, this, metadata);
  }
 
+ public boolean registerSetting(Setting<?> setting) {
+ validateSettingKey(setting);
+ return super.registerSetting(setting);
+ }
+
  @Override
  protected void validateSettingKey(Setting setting) {
  if (setting.getKey().startsWith("index.") == false) {

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

@@ -179,6 +179,29 @@ public void configure(Binder binder) {
  binder.bind(IndexScopedSettings.class).toInstance(indexScopedSettings);
  }
 
+ /**
+ * Dynamically registers a new Setting at Runtime. This method is mostly used by plugins/extensions
+ * to register new settings at runtime. Settings can be of Node Scope or Index Scope.
+ * @param setting which is being registered in the cluster.
+ * @return boolean value is set to true when successfully registered, else returns false
+ */
+ public boolean registerDynamicSetting(Setting<?> setting) {
+ try {
+ registerSetting(setting);
+ if (setting.hasNodeScope()) {
+ return clusterSettings.registerSetting(setting);
+ }
+ if (setting.hasIndexScope()) {
+ return indexScopedSettings.registerSetting(setting);
+ }
+ logger.info("Registered new Setting: " + setting.getKey() + " successfully ");
+ } catch (Exception e) {
+ logger.error("Could not register setting " + setting.getKey());
+ throw new SettingsException("Could not register setting:" + setting.getKey());
+ }
+ return false;
+ }
+
  /**
  * Registers a new setting. This method should be used by plugins in order to expose any custom settings the plugin defines.
  * Unless a setting is registered the setting is unusable. If a setting is never the less specified the node will reject

server/src/test/java/org/opensearch/common/settings/SettingsModuleTests.java

@@ -237,4 +237,46 @@ public void testOldMaxClauseCountSetting() {
  ex.getMessage()
  );
  }
+
+ public void testDynamicNodeSettingsRegistration() {
+ Settings settings = Settings.builder().put("some.custom.setting", "2.0").build();
+ SettingsModule module = new SettingsModule(settings, Setting.floatSetting("some.custom.setting", 1.0f, Property.NodeScope));
+ assertNotNull(module.getClusterSettings().get("some.custom.setting"));
+ // For unregistered setting the value is expected to be null
+ assertNull(module.getClusterSettings().get("some.custom.setting2"));
+ assertInstanceBinding(module, Settings.class, (s) -> s == settings);
+
+ assertTrue(module.registerDynamicSetting(Setting.floatSetting("some.custom.setting2", 1.0f, Property.NodeScope)));
+ assertNotNull(module.getClusterSettings().get("some.custom.setting2"));
+
+ // verify if some.custom.setting still exists
+ assertNotNull(module.getClusterSettings().get("some.custom.setting"));
+
+ // verify exception is thrown when setting registration fails
+ expectThrows(
+ SettingsException.class,
+ () -> module.registerDynamicSetting(Setting.floatSetting("some.custom.setting", 1.0f, Property.NodeScope))
+ );
+ }
+
+ public void testDynamicIndexSettingsRegistration() {
+ Settings settings = Settings.builder().put("some.custom.setting", "2.0").build();
+ SettingsModule module = new SettingsModule(settings, Setting.floatSetting("some.custom.setting", 1.0f, Property.NodeScope));
+ assertNotNull(module.getClusterSettings().get("some.custom.setting"));
+ // For unregistered setting the value is expected to be null
+ assertNull(module.getIndexScopedSettings().get("index.custom.setting2"));
+ assertInstanceBinding(module, Settings.class, (s) -> s == settings);
+
+ assertTrue(module.registerDynamicSetting(Setting.floatSetting("index.custom.setting2", 1.0f, Property.IndexScope)));
+ assertNotNull(module.getIndexScopedSettings().get("index.custom.setting2"));
+
+ // verify if some.custom.setting still exists
+ assertNotNull(module.getClusterSettings().get("some.custom.setting"));
+
+ // verify exception is thrown when setting registration fails
+ expectThrows(
+ SettingsException.class,
+ () -> module.registerDynamicSetting(Setting.floatSetting("index.custom.setting2", 1.0f, Property.IndexScope))
+ );
+ }
 }