Refactor handler method

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

@@ -56,7 +56,7 @@ protected ExtensionRestRequest(RestExecuteOnExtensionRequest request) throws Ill
     /**
      * Object generated from input stream
      * @param in Input stream
-     * @throws IOException
+     * @throws IOException if there a error generating object from input stream
      */
     public ExtensionRestRequest(StreamInput in) throws IOException {
         super(in);
@@ -68,7 +68,7 @@ public ExtensionRestRequest(StreamInput in) throws IOException {
     /**
      * Write this object to output stream
      * @param out the writeable output stream
-     * @throws IOException
+     * @throws IOException if there is an error writing object to output stream
      */
     @Override
     public void writeTo(StreamOutput out) throws IOException {

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

@@ -15,22 +15,18 @@
 import org.opensearch.Version;
 import org.opensearch.cluster.ClusterModule;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.io.stream.NamedWriteableRegistryParseRequest;
 import org.opensearch.extensions.OpenSearchRequest;
 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;
 import org.opensearch.discovery.InitializeExtensionsRequest;
-import org.opensearch.discovery.InitializeExtensionsResponse;
 import org.opensearch.extensions.ExtensionActionListenerOnFailureRequest;
 import org.opensearch.extensions.DiscoveryExtension;
 import org.opensearch.extensions.EnvironmentSettingsRequest;
@@ -39,31 +35,32 @@
 import org.opensearch.extensions.ExtensionRequest;
 import org.opensearch.extensions.ExtensionsOrchestrator;
 import org.opensearch.index.IndicesModuleRequest;
-import org.opensearch.index.IndicesModuleResponse;
 import org.opensearch.indices.IndicesModule;
 import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.breaker.NoneCircuitBreakerService;
-import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.RestHandler.Route;
-import org.opensearch.rest.RestResponse;
 import org.opensearch.transport.netty4.Netty4Transport;
 import org.opensearch.transport.SharedGroupFactory;
 import org.opensearch.sdk.handlers.ActionListenerOnFailureResponseHandler;
 import org.opensearch.sdk.handlers.ClusterSettingsResponseHandler;
 import org.opensearch.sdk.handlers.ClusterStateResponseHandler;
 import org.opensearch.sdk.handlers.EnvironmentSettingsResponseHandler;
 import org.opensearch.sdk.handlers.ExtensionBooleanResponseHandler;
+import org.opensearch.sdk.handlers.ExtensionsIndicesModuleNameRequestHandler;
+import org.opensearch.sdk.handlers.ExtensionsIndicesModuleRequestHandler;
+import org.opensearch.sdk.handlers.ExtensionsInitRequestHandler;
+import org.opensearch.sdk.handlers.ExtensionsRestRequestHandler;
 import org.opensearch.sdk.handlers.LocalNodeResponseHandler;
 import org.opensearch.sdk.handlers.UpdateSettingsRequestHandler;
 import org.opensearch.sdk.handlers.ExtensionStringResponseHandler;
+import org.opensearch.sdk.handlers.OpensearchRequestHandler;
 import org.opensearch.search.SearchModule;
 import org.opensearch.threadpool.ThreadPool;
 import org.opensearch.transport.ClusterConnectionManager;
 import org.opensearch.transport.ConnectionManager;
 import org.opensearch.transport.TransportInterceptor;
 import org.opensearch.transport.TransportService;
 import org.opensearch.transport.TransportSettings;
-import org.opensearch.transport.TransportResponse;
 
 import java.io.File;
 import java.io.IOException;
@@ -91,23 +88,46 @@ public class ExtensionsRunner {
     private static final String NODE_NAME_SETTING = "node.name";
 
     private String uniqueId;
-    private DiscoveryNode opensearchNode;
+    /**
+     * This method is call from {@link ExtensionsInitRequestHandler}.
+     */
+    public DiscoveryNode opensearchNode;
     private DiscoveryExtension extensionNode;
-    private TransportService extensionTransportService = null;
+    /**
+     * This method is call from {@link ExtensionsInitRequestHandler}.
+     */
+    public TransportService extensionTransportService = null;
     // The routes and classes which handle the REST requests
     private final ExtensionRestPathRegistry extensionRestPathRegistry = new ExtensionRestPathRegistry();
     // Custom settings from the extension's getSettings
+    /**
+     * This method is call from {@link ExtensionsInitRequestHandler}.
+     */
     private final List<Setting<?>> customSettings;
     // Node name, host, and port
-    private final Settings settings;
+    /**
+     * This method is call from {@link ExtensionsInitRequestHandler}.
+     */
+    public final Settings settings;
     private final TransportInterceptor NOOP_TRANSPORT_INTERCEPTOR = new TransportInterceptor() {
     };
     private NamedWriteableRegistryAPI namedWriteableRegistryApi = new NamedWriteableRegistryAPI();
+    private ExtensionsInitRequestHandler extensionsInitRequestHandler = new ExtensionsInitRequestHandler();
+    private OpensearchRequestHandler opensearchRequestHandler = new OpensearchRequestHandler();
+    private ExtensionsIndicesModuleRequestHandler extensionsIndicesModuleRequestHandler = new ExtensionsIndicesModuleRequestHandler();
+    private ExtensionsIndicesModuleNameRequestHandler extensionsIndicesModuleNameRequestHandler =
+        new ExtensionsIndicesModuleNameRequestHandler();
+    private ExtensionsRestRequestHandler extensionsRestRequestHandler = new ExtensionsRestRequestHandler();
+
     /*
      * TODO: expose an interface for extension to register actions
      * https://github.com/opensearch-project/opensearch-sdk-java/issues/119
      */
-    private TransportActions transportActions = new TransportActions(new HashMap<>());
+    /**
+     * This method is call from {@link ExtensionsInitRequestHandler}.
+     */
+    public TransportActions transportActions = new TransportActions(new HashMap<>());
+
     /**
      * Instantiates a new update settings request handler
      */
@@ -161,131 +181,38 @@ private static ExtensionSettings readExtensionSettings() throws IOException {
         return objectMapper.readValue(file, ExtensionSettings.class);
     }
 
+    /**
+     * This method is call from {@link ExtensionsInitRequestHandler}.
+     * @param extensionTransportService assign value for extensionTransportService
+     */
     void setExtensionTransportService(TransportService extensionTransportService) {
         this.extensionTransportService = extensionTransportService;
     }
 
-    private void setUniqueId(String id) {
+    /**
+     * This method is call from {@link ExtensionsInitRequestHandler}.
+     * @param id assign value for id
+     */
+    public void setUniqueId(String id) {
         this.uniqueId = id;
     }
 
     String getUniqueId() {
         return uniqueId;
     }
 
-    private void setOpensearchNode(DiscoveryNode opensearchNode) {
+    public void setOpensearchNode(DiscoveryNode opensearchNode) {
         this.opensearchNode = opensearchNode;
     }
 
-    private void setExtensionNode(DiscoveryExtension extensionNode) {
+    public void setExtensionNode(DiscoveryExtension extensionNode) {
         this.extensionNode = extensionNode;
     }
 
     DiscoveryNode getOpensearchNode() {
         return opensearchNode;
     }
 
-    /**
-     * Handles a extension request from OpenSearch.  This is the first request for the transport communication and will initialize the extension and will be a part of OpenSearch bootstrap.
-     *
-     * @param extensionInitRequest  The request to handle.
-     * @return A response to OpenSearch validating that this is an extension.
-     */
-    InitializeExtensionsResponse handleExtensionInitRequest(InitializeExtensionsRequest extensionInitRequest) {
-        logger.info("Registering Extension Request received from OpenSearch");
-        opensearchNode = extensionInitRequest.getSourceNode();
-        setUniqueId(extensionInitRequest.getExtension().getId());
-        // Successfully initialized. Send the response.
-        try {
-            return new InitializeExtensionsResponse(settings.get(NODE_NAME_SETTING));
-        } finally {
-            // After sending successful response to initialization, send the REST API and Settings
-            setOpensearchNode(opensearchNode);
-            setExtensionNode(extensionInitRequest.getExtension());
-            extensionTransportService.connectToNode(opensearchNode);
-            sendRegisterRestActionsRequest(extensionTransportService);
-            sendRegisterCustomSettingsRequest(extensionTransportService);
-            transportActions.sendRegisterTransportActionsRequest(extensionTransportService, opensearchNode);
-        }
-    }
-
-    /**
-     * Handles a request from OpenSearch and invokes the extension point API corresponding with the request type
-     *
-     * @param request  The request to handle.
-     * @return A response to OpenSearch for the corresponding API
-     * @throws Exception if the corresponding handler for the request is not present
-     */
-    TransportResponse handleOpenSearchRequest(OpenSearchRequest request) throws Exception {
-        // Read enum
-        switch (request.getRequestType()) {
-            case REQUEST_OPENSEARCH_NAMED_WRITEABLE_REGISTRY:
-                return namedWriteableRegistryApi.handleNamedWriteableRegistryRequest(request);
-            // Add additional request handlers here
-            default:
-                throw new Exception("Handler not present for the provided request");
-        }
-    }
-
-    /**
-     * Handles a request for extension point indices from OpenSearch.  The {@link #handleExtensionInitRequest(InitializeExtensionsRequest)} method must have been called first to initialize the extension.
-     *
-     * @param indicesModuleRequest  The request to handle.
-     * @param transportService  The transport service communicating with OpenSearch.
-     * @return A response to OpenSearch with this extension's index and search listeners.
-     */
-    IndicesModuleResponse handleIndicesModuleRequest(IndicesModuleRequest indicesModuleRequest, TransportService transportService) {
-        logger.info("Registering Indices Module Request received from OpenSearch");
-        IndicesModuleResponse indicesModuleResponse = new IndicesModuleResponse(true, true, true);
-        return indicesModuleResponse;
-    }
-
-    /**
-     * Handles a request for extension name from OpenSearch.  The {@link #handleExtensionInitRequest(InitializeExtensionsRequest)} method must have been called first to initialize the extension.
-     *
-     * @param indicesModuleRequest  The request to handle.
-     * @return A response acknowledging the request.
-     */
-    ExtensionBooleanResponse handleIndicesModuleNameRequest(IndicesModuleRequest indicesModuleRequest) {
-        // Works as beforeIndexRemoved
-        logger.info("Registering Indices Module Name Request received from OpenSearch");
-        ExtensionBooleanResponse indicesModuleNameResponse = new ExtensionBooleanResponse(true);
-        return indicesModuleNameResponse;
-    }
-
-    /**
-     * Handles a request from OpenSearch to execute a REST request on the extension.
-     *
-     * @param request  The REST request to execute.
-     * @return A response acknowledging the request.
-     */
-    RestExecuteOnExtensionResponse handleRestExecuteOnExtensionRequest(RestExecuteOnExtensionRequest request) {
-
-        ExtensionRestHandler restHandler = extensionRestPathRegistry.getHandler(request.getMethod(), request.getUri());
-        if (restHandler == null) {
-            return new RestExecuteOnExtensionResponse(
-                RestStatus.NOT_FOUND,
-                "No handler for " + ExtensionRestPathRegistry.restPathToString(request.getMethod(), request.getUri())
-            );
-        }
-        // ExtensionRestRequest restRequest = new ExtensionRestRequest(request);
-        ExtensionRestRequest restRequest = new ExtensionRestRequest(
-            request.getMethod(),
-            request.getUri(),
-            request.getRequestIssuerIdentity()
-        );
-
-        // Get response from extension
-        RestResponse response = restHandler.handleRequest(restRequest);
-        logger.info("Sending extension response to OpenSearch: " + response.status());
-        return new RestExecuteOnExtensionResponse(
-            response.status(),
-            response.contentType(),
-            BytesReference.toBytes(response.content()),
-            response.getHeaders()
-        );
-    }
-
     /**
      * Initializes a Netty4Transport object. This object will be wrapped in a {@link TransportService} object.
      *
@@ -381,7 +308,7 @@ public void startTransportService(TransportService transportService) {
             false,
             false,
             InitializeExtensionsRequest::new,
-            (request, channel, task) -> channel.sendResponse(handleExtensionInitRequest(request))
+            (request, channel, task) -> channel.sendResponse(extensionsInitRequestHandler.handleExtensionInitRequest(request, this))
         );
 
         transportService.registerRequestHandler(
@@ -390,7 +317,7 @@ public void startTransportService(TransportService transportService) {
             false,
             false,
             OpenSearchRequest::new,
-            (request, channel, task) -> channel.sendResponse(handleOpenSearchRequest(request))
+            (request, channel, task) -> channel.sendResponse(opensearchRequestHandler.handleOpenSearchRequest(request))
         );
 
         transportService.registerRequestHandler(
@@ -408,7 +335,9 @@ public void startTransportService(TransportService transportService) {
             false,
             false,
             IndicesModuleRequest::new,
-            ((request, channel, task) -> channel.sendResponse(handleIndicesModuleRequest(request, transportService)))
+            ((request, channel, task) -> channel.sendResponse(
+                extensionsIndicesModuleRequestHandler.handleIndicesModuleRequest(request, transportService)
+            ))
 
         );
 
@@ -418,7 +347,9 @@ public void startTransportService(TransportService transportService) {
             false,
             false,
             IndicesModuleRequest::new,
-            ((request, channel, task) -> channel.sendResponse(handleIndicesModuleNameRequest(request)))
+            ((request, channel, task) -> channel.sendResponse(
+                extensionsIndicesModuleNameRequestHandler.handleIndicesModuleNameRequest(request)
+            ))
         );
 
         transportService.registerRequestHandler(
@@ -427,7 +358,7 @@ public void startTransportService(TransportService transportService) {
             false,
             false,
             RestExecuteOnExtensionRequest::new,
-            ((request, channel, task) -> channel.sendResponse(handleRestExecuteOnExtensionRequest(request)))
+            ((request, channel, task) -> channel.sendResponse(extensionsRestRequestHandler.handleRestExecuteOnExtensionRequest(request)))
         );
 
         transportService.registerRequestHandler(

src/main/java/org/opensearch/sdk/handlers/ExtensionsIndicesModuleNameRequestHandler.java

@@ -0,0 +1,36 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.sdk.handlers;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.extensions.ExtensionBooleanResponse;
+import org.opensearch.sdk.ExtensionsRunner;
+import org.opensearch.index.IndicesModuleRequest;
+
+/**
+ * This class handles the request from OpenSearch to a {@link ExtensionsRunner#startTransportService(TransportService transportService)} call.
+ */
+
+public class ExtensionsIndicesModuleNameRequestHandler {
+    private static final Logger logger = LogManager.getLogger(ExtensionsIndicesModuleNameRequestHandler.class);
+
+    /**
+     * Handles a request for extension name from OpenSearch.  The {@link ExtensionsInitRequestHandler} method must have been called first to initialize the extension.
+     *
+     * @param indicesModuleRequest  The request to handle.
+     * @return A response acknowledging the request.
+     */
+    public ExtensionBooleanResponse handleIndicesModuleNameRequest(IndicesModuleRequest indicesModuleRequest) {
+        // Works as beforeIndexRemoved
+        logger.info("Registering Indices Module Name Request received from OpenSearch");
+        ExtensionBooleanResponse indicesModuleNameResponse = new ExtensionBooleanResponse(true);
+        return indicesModuleNameResponse;
+    }
+
+}

src/main/java/org/opensearch/sdk/handlers/ExtensionsIndicesModuleRequestHandler.java

@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+package org.opensearch.sdk.handlers;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.index.IndicesModuleRequest;
+import org.opensearch.index.IndicesModuleResponse;
+import org.opensearch.sdk.ExtensionsRunner;
+import org.opensearch.transport.TransportService;
+
+/**
+ * This class handles the request from OpenSearch to a {@link ExtensionsRunner#startTransportService(TransportService transportService)} call.
+ */
+
+public class ExtensionsIndicesModuleRequestHandler {
+    private static final Logger logger = LogManager.getLogger(ExtensionsIndicesModuleRequestHandler.class);
+
+    /**
+     * Handles a request for extension point indices from OpenSearch.  The {@link ExtensionsInitRequestHandler} class must have been called first to initialize the extension.
+     *
+     * @param indicesModuleRequest  The request to handle.
+     * @param transportService  The transport service communicating with OpenSearch.
+     * @return A response to OpenSearch with this extension's index and search listeners.
+     */
+    public IndicesModuleResponse handleIndicesModuleRequest(IndicesModuleRequest indicesModuleRequest, TransportService transportService) {
+        logger.info("Registering Indices Module Request received from OpenSearch");
+        IndicesModuleResponse indicesModuleResponse = new IndicesModuleResponse(true, true, true);
+        return indicesModuleResponse;
+    }
+
+}