Add getSettings support for AD

src/main/java/org/opensearch/sdk/Extension.java

@@ -10,8 +10,11 @@
 import java.io.File;
 import java.io.IOException;
 import java.net.URL;
+import java.util.Collections;
 import java.util.List;
 
+import org.opensearch.common.settings.Setting;
+
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
 
@@ -36,6 +39,15 @@ public interface Extension {
      */
     List<ExtensionRestHandler> getExtensionRestHandlers();
 
+    /**
+     * Gets an optional list of custom {@link Setting} for the extension to register with OpenSearch.
+     *
+     * @return a list of custom settings this extension uses.
+     */
+    default List<Setting<?>> getSettings() {
+        return Collections.emptyList();
+    }
+
     /**
      * Helper method to read extension settings from a YAML file.
      *

src/main/java/org/opensearch/sdk/ExtensionRestHandler.java

@@ -23,6 +23,8 @@ public interface ExtensionRestHandler {
 
     /**
      * The list of {@link Route}s that this ExtensionRestHandler is responsible for handling.
+     *
+     * @return The routes this handler will handle.
      */
     List<Route> routes();
 

src/main/java/org/opensearch/sdk/ExtensionsRunner.java

@@ -22,8 +22,10 @@
 import org.opensearch.extensions.rest.RegisterRestActionsRequest;
 import org.opensearch.extensions.rest.RestExecuteOnExtensionRequest;
 import org.opensearch.extensions.rest.RestExecuteOnExtensionResponse;
+import org.opensearch.extensions.settings.RegisterCustomSettingsRequest;
 import org.opensearch.common.network.NetworkModule;
 import org.opensearch.common.network.NetworkService;
+import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.extensions.ExtensionBooleanResponse;
@@ -45,7 +47,7 @@
 import org.opensearch.sdk.handlers.ClusterSettingsResponseHandler;
 import org.opensearch.sdk.handlers.ClusterStateResponseHandler;
 import org.opensearch.sdk.handlers.LocalNodeResponseHandler;
-import org.opensearch.sdk.handlers.RegisterRestActionsResponseHandler;
+import org.opensearch.sdk.handlers.ExtensionStringResponseHandler;
 import org.opensearch.search.SearchModule;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ClusterConnectionManager;
@@ -80,8 +82,11 @@ public class ExtensionsRunner {
     private String uniqueId;
     private DiscoveryNode opensearchNode;
     private TransportService extensionTransportService = null;
-    private ExtensionRestPathRegistry extensionRestPathRegistry = new ExtensionRestPathRegistry();
-
+    // The routes and classes which handle the REST requests
+    private final ExtensionRestPathRegistry extensionRestPathRegistry = new ExtensionRestPathRegistry();
+    // Custom settings from the extension's getSettings
+    private final List<Setting<?>> customSettings;
+    // Node name, host, and port
     private final Settings settings;
     private final TransportInterceptor NOOP_TRANSPORT_INTERCEPTOR = new TransportInterceptor() {
     };
@@ -104,6 +109,7 @@ public ExtensionsRunner() throws IOException {
             .put(TransportSettings.BIND_HOST.getKey(), extensionSettings.getHostAddress())
             .put(TransportSettings.PORT.getKey(), extensionSettings.getHostPort())
             .build();
+        this.customSettings = Collections.emptyList();
     }
 
     /**
@@ -119,12 +125,14 @@ private ExtensionsRunner(Extension extension) throws IOException {
             .put(TransportSettings.BIND_HOST.getKey(), extensionSettings.getHostAddress())
             .put(TransportSettings.PORT.getKey(), extensionSettings.getHostPort())
             .build();
-        // store rest handlers in the map
+        // store REST handlers in the registry
         for (ExtensionRestHandler extensionRestHandler : extension.getExtensionRestHandlers()) {
             for (Route route : extensionRestHandler.routes()) {
                 extensionRestPathRegistry.registerHandler(route.getMethod(), route.getPath(), extensionRestHandler);
             }
         }
+        // save custom settings
+        this.customSettings = extension.getSettings();
         // initialize the transport service
         this.initializeExtensionTransportService(this.getSettings());
         // start listening on configured port and wait for connection from OpenSearch
@@ -171,10 +179,11 @@ InitializeExtensionsResponse handleExtensionInitRequest(InitializeExtensionsRequ
         try {
             return new InitializeExtensionsResponse(settings.get(NODE_NAME_SETTING));
         } finally {
-            // After sending successful response to initialization, send the REST API
+            // After sending successful response to initialization, send the REST API and Settings
             setOpensearchNode(opensearchNode);
             extensionTransportService.connectToNode(opensearchNode);
             sendRegisterRestActionsRequest(extensionTransportService);
+            sendRegisterCustomSettingsRequest(extensionTransportService);
             transportActions.sendRegisterTransportActionsRequest(extensionTransportService, opensearchNode);
         }
     }
@@ -403,7 +412,7 @@ public void startTransportService(TransportService transportService) {
     public void sendRegisterRestActionsRequest(TransportService transportService) {
         List<String> extensionRestPaths = extensionRestPathRegistry.getRegisteredPaths();
         logger.info("Sending Register REST Actions request to OpenSearch for " + extensionRestPaths);
-        RegisterRestActionsResponseHandler registerActionsResponseHandler = new RegisterRestActionsResponseHandler();
+        ExtensionStringResponseHandler registerActionsResponseHandler = new ExtensionStringResponseHandler();
         try {
             transportService.sendRequest(
                 opensearchNode,
@@ -416,6 +425,26 @@ public void sendRegisterRestActionsRequest(TransportService transportService) {
         }
     }
 
+    /**
+     * Requests that OpenSearch register the custom settings for this extension.
+     *
+     * @param transportService  The TransportService defining the connection to OpenSearch.
+     */
+    public void sendRegisterCustomSettingsRequest(TransportService transportService) {
+        logger.info("Sending Settings request to OpenSearch");
+        ExtensionStringResponseHandler registerCustomSettingsResponseHandler = new ExtensionStringResponseHandler();
+        try {
+            transportService.sendRequest(
+                opensearchNode,
+                ExtensionsOrchestrator.REQUEST_EXTENSION_REGISTER_CUSTOM_SETTINGS,
+                new RegisterCustomSettingsRequest(getUniqueId(), customSettings),
+                registerCustomSettingsResponseHandler
+            );
+        } catch (Exception e) {
+            logger.info("Failed to send Register Settings request to OpenSearch", e);
+        }
+    }
+
     /**
      * Requests the cluster state from OpenSearch.  The result will be handled by a {@link ClusterStateResponseHandler}.
      *
@@ -509,7 +538,7 @@ private Settings getSettings() {
      *
      * @param timeout  The timeout for the listener in milliseconds. A timeout of 0 means no timeout.
      */
-    public static void startActionListener(int timeout) {
+    public void startActionListener(int timeout) {
         final ActionListener actionListener = new ActionListener();
         actionListener.runActionListener(true, timeout);
     }

src/main/java/org/opensearch/sdk/SDKClient.java

@@ -52,6 +52,7 @@ public OpenSearchClient initializeClient(String hostAddress, int port) throws IO
     }
 
     /**
+     * Close this client.
      *
      * @throws IOException if closing the restClient fails
      */

src/main/java/org/opensearch/sdk/TransportActions.java

@@ -15,7 +15,7 @@
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.extensions.ExtensionsOrchestrator;
 import org.opensearch.extensions.RegisterTransportActionsRequest;
-import org.opensearch.sdk.handlers.ExtensionResponseHandler;
+import org.opensearch.sdk.handlers.ExtensionBooleanResponseHandler;
 import org.opensearch.transport.TransportService;
 
 import java.util.HashMap;
@@ -30,6 +30,9 @@ public class TransportActions {
 
     /**
      * Constructor for TransportActions. Creates a map of transportActions for this extension.
+     *
+     * @param <Request> the TransportAction request
+     * @param <Response> the TransportAction response
      * @param transportActions is the list of actions the extension would like to register with OpenSearch.
      */
     public <Request extends ActionRequest, Response extends ActionResponse> TransportActions(
@@ -46,7 +49,7 @@ public <Request extends ActionRequest, Response extends ActionResponse> Transpor
      */
     public void sendRegisterTransportActionsRequest(TransportService transportService, DiscoveryNode opensearchNode) {
         logger.info("Sending Register Transport Actions request to OpenSearch");
-        ExtensionResponseHandler registerTransportActionsResponseHandler = new ExtensionResponseHandler();
+        ExtensionBooleanResponseHandler registerTransportActionsResponseHandler = new ExtensionBooleanResponseHandler();
         try {
             transportService.sendRequest(
                 opensearchNode,

src/main/java/org/opensearch/sdk/handlers/ExtensionResponseHandler.java → src/main/java/org/opensearch/sdk/handlers/ExtensionBooleanResponseHandler.java

@@ -20,8 +20,8 @@
 /**
  * This class handles the response {{@link org.opensearch.extensions.ExtensionBooleanResponse }} from OpenSearch to Extension.
  */
-public class ExtensionResponseHandler implements TransportResponseHandler<ExtensionBooleanResponse> {
-    private static final Logger logger = LogManager.getLogger(ExtensionResponseHandler.class);
+public class ExtensionBooleanResponseHandler implements TransportResponseHandler<ExtensionBooleanResponse> {
+    private static final Logger logger = LogManager.getLogger(ExtensionBooleanResponseHandler.class);
 
     @Override
     public void handleResponse(ExtensionBooleanResponse response) {

src/main/java/org/opensearch/sdk/handlers/RegisterRestActionsResponseHandler.java → src/main/java/org/opensearch/sdk/handlers/ExtensionStringResponseHandler.java

@@ -10,29 +10,26 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.extensions.rest.RegisterRestActionsResponse;
-import org.opensearch.sdk.ExtensionsRunner;
+import org.opensearch.extensions.ExtensionStringResponse;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.TransportException;
 import org.opensearch.transport.TransportResponseHandler;
-import org.opensearch.transport.TransportService;
-
 import java.io.IOException;
 
 /**
- * This class handles the response from OpenSearch to a {@link ExtensionsRunner#sendRegisterRestActionsRequest(TransportService)} call.
+ * This class handles the response from OpenSearch to call returning an {@link ExtensionStringResponse}.
  */
-public class RegisterRestActionsResponseHandler implements TransportResponseHandler<RegisterRestActionsResponse> {
-    private static final Logger logger = LogManager.getLogger(RegisterRestActionsResponseHandler.class);
+public class ExtensionStringResponseHandler implements TransportResponseHandler<ExtensionStringResponse> {
+    private static final Logger logger = LogManager.getLogger(ExtensionStringResponseHandler.class);
 
     @Override
-    public void handleResponse(RegisterRestActionsResponse response) {
+    public void handleResponse(ExtensionStringResponse response) {
         logger.info("received {}", response.getResponse());
     }
 
     @Override
     public void handleException(TransportException exp) {
-        logger.info("RegisterActionsRequest failed", exp);
+        logger.info("Request failed", exp);
     }
 
     @Override
@@ -41,7 +38,7 @@ public String executor() {
     }
 
     @Override
-    public RegisterRestActionsResponse read(StreamInput in) throws IOException {
-        return new RegisterRestActionsResponse(in);
+    public ExtensionStringResponse read(StreamInput in) throws IOException {
+        return new ExtensionStringResponse(in);
     }
 }

src/test/java/org/opensearch/sdk/TestExtensionTransportActionsAPI.java

@@ -13,7 +13,7 @@
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.extensions.ExtensionsOrchestrator;
-import org.opensearch.sdk.handlers.ExtensionResponseHandler;
+import org.opensearch.sdk.handlers.ExtensionBooleanResponseHandler;
 import org.opensearch.tasks.Task;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.Transport;
@@ -87,7 +87,7 @@ public void testRegisterTransportAction() {
             any(),
             eq(ExtensionsOrchestrator.REQUEST_EXTENSION_REGISTER_TRANSPORT_ACTIONS),
             any(),
-            any(ExtensionResponseHandler.class)
+            any(ExtensionBooleanResponseHandler.class)
         );
     }
 }

src/test/java/org/opensearch/sdk/TestExtensionsRunner.java

@@ -49,7 +49,7 @@
 import org.opensearch.sdk.handlers.ClusterSettingsResponseHandler;
 import org.opensearch.sdk.handlers.ClusterStateResponseHandler;
 import org.opensearch.sdk.handlers.LocalNodeResponseHandler;
-import org.opensearch.sdk.handlers.RegisterRestActionsResponseHandler;
+import org.opensearch.sdk.handlers.ExtensionStringResponseHandler;
 import org.opensearch.test.OpenSearchTestCase;
 import org.opensearch.transport.Transport;
 import org.opensearch.transport.TransportService;
@@ -198,6 +198,14 @@ public void testRegisterRestActionsRequest() {
 
         extensionsRunner.sendRegisterRestActionsRequest(transportService);
 
-        verify(transportService, times(1)).sendRequest(any(), anyString(), any(), any(RegisterRestActionsResponseHandler.class));
+        verify(transportService, times(1)).sendRequest(any(), anyString(), any(), any(ExtensionStringResponseHandler.class));
+    }
+
+    @Test
+    public void testRegisterCustomSettingsRequest() {
+
+        extensionsRunner.sendRegisterCustomSettingsRequest(transportService);
+
+        verify(transportService, times(1)).sendRequest(any(), anyString(), any(), any(ExtensionStringResponseHandler.class));
     }
 }