[Extensions] Adding cross version support for registering Transport A…

…ctions (#7403)

* Adding cross version support for RegisterTransportActions for extensions

Signed-off-by: Sarat Vemulapalli <vemulapallisarat@gmail.com>

CHANGELOG.md

@@ -86,10 +86,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased 2.x]
 ### Added
-- [Extensions] Moving Extensions APIs to protobuf serialization. ([#6960](https://github.com/opensearch-project/OpenSearch/pull/6960))
+- [Extensions] Moving Extensions APIs to support cross versions via protobuf. ([#7402](https://github.com/opensearch-project/OpenSearch/issues/7402))
 - [Extensions] Add IdentityPlugin into core to support Extension identities ([#7246](https://github.com/opensearch-project/OpenSearch/pull/7246))
 - Add descending order search optimization through reverse segment read. ([#7244](https://github.com/opensearch-project/OpenSearch/pull/7244))
-- [Extensions] Moving RestActions APIs to protobuf serialization. ([#7302](https://github.com/opensearch-project/OpenSearch/pull/7302))
 
 ### Dependencies
 - Bump `jackson` from 2.14.2 to 2.15.0 ([#7286](https://github.com/opensearch-project/OpenSearch/pull/7286)

DEVELOPER_GUIDE.md

@@ -9,6 +9,7 @@
       - [Windows](#windows)
       - [Docker](#docker)
     - [Build](#build)
+      - [Generated Code](#generated-code)
     - [Run Tests](#run-tests)
     - [Run OpenSearch](#run-opensearch)
   - [Use an Editor](#use-an-editor)
@@ -134,6 +135,17 @@ To build a distribution to run on your local platform, run:
 
 All distributions built will be under `distributions/archives`.
 
+#### Generated Code
+
+OpenSearch uses code generators like [Protobuf](https://protobuf.dev/).
+OpenSearch build system already takes a dependency of generating code from protobuf, incase you run into compilation errors, run:
+
+```
+./gradlew generateProto
+```
+
+Generated code in OpenSearch is used to establish cross version compatibility communication for API contracts within OpenSearch.
+
 ### Run Tests
 
 OpenSearch uses a Gradle wrapper for its build. Run `gradlew` on Unix systems, or `gradlew.bat` on Windows in the root of the repository.

server/build.gradle

@@ -359,6 +359,8 @@ tasks.named("missingJavadoc").configure {
     "org.opensearch.extensions.proto.RegisterRestActionsProto.RegisterRestActionsOrBuilder",
     "org.opensearch.extensions.proto.ExtensionRequestProto",
     "org.opensearch.extensions.proto.ExtensionRequestProto.ExtensionRequestOrBuilder",
+    "org.opensearch.extensions.proto.RegisterTransportActionsProto",
+    "org.opensearch.extensions.proto.RegisterTransportActionsProto.RegisterTransportActionsOrBuilder",
     "org.opensearch.extensions.proto"
   ]
 }

server/src/main/java/org/opensearch/extensions/action/RegisterTransportActionsRequest.java

@@ -10,10 +10,12 @@
 
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.extensions.proto.RegisterTransportActionsProto.RegisterTransportActions;
+import org.opensearch.extensions.proto.ExtensionIdentityProto.ExtensionIdentity;
 import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
-import java.util.HashSet;
+import java.util.List;
 import java.util.Objects;
 import java.util.Set;
 
@@ -23,52 +25,48 @@
  * @opensearch.internal
  */
 public class RegisterTransportActionsRequest extends TransportRequest {
-    // The uniqueId defining the extension which runs this action
-    private String uniqueId;
-    // The action names to register
-    private Set<String> transportActions;
+    private final RegisterTransportActions request;
 
     public RegisterTransportActionsRequest(String uniqueId, Set<String> transportActions) {
-        this.uniqueId = uniqueId;
-        this.transportActions = transportActions;
+        ExtensionIdentity identity = ExtensionIdentity.newBuilder().setUniqueId(uniqueId).build();
+        this.request = RegisterTransportActions.newBuilder().setIdentity(identity).addAllTransportActions(transportActions).build();
     }
 
     public RegisterTransportActionsRequest(StreamInput in) throws IOException {
         super(in);
-        this.uniqueId = in.readString();
-        this.transportActions = new HashSet<>(in.readStringList());
+        this.request = RegisterTransportActions.parseFrom(in.readByteArray());
     }
 
     public String getUniqueId() {
-        return uniqueId;
+        return request.getIdentity().getUniqueId();
     }
 
-    public Set<String> getTransportActions() {
-        return transportActions;
+    public List<String> getTransportActions() {
+        return request.getTransportActionsList();
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        out.writeString(uniqueId);
-        out.writeStringCollection(transportActions);
+        out.writeByteArray(request.toByteArray());
     }
 
     @Override
     public String toString() {
-        return "TransportActionsRequest{uniqueId=" + uniqueId + ", actions=" + transportActions + "}";
+        return "TransportActionsRequest{Identity=" + request.getIdentity() + ", actions=" + request.getTransportActionsList() + "}";
     }
 
     @Override
     public boolean equals(Object obj) {
         if (this == obj) return true;
         if (obj == null || getClass() != obj.getClass()) return false;
         RegisterTransportActionsRequest that = (RegisterTransportActionsRequest) obj;
-        return Objects.equals(uniqueId, that.uniqueId) && Objects.equals(transportActions, that.transportActions);
+        return Objects.equals(request.getIdentity().getUniqueId(), that.request.getIdentity().getUniqueId())
+            && Objects.equals(request.getTransportActionsList(), that.request.getTransportActionsList());
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(uniqueId, transportActions);
+        return Objects.hash(request.getIdentity(), request.getTransportActionsList());
     }
 }

server/src/main/proto/extensions/RegisterTransportActionsProto.proto

@@ -0,0 +1,21 @@
+/*
+ * 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.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+syntax = "proto3";
+package org.opensearch.extensions.proto;
+
+import "extensions/ExtensionIdentityProto.proto";
+option java_outer_classname = "RegisterTransportActionsProto";
+
+message RegisterTransportActions {
+  ExtensionIdentity identity = 1;
+  repeated string transportActions = 2;
+}

server/src/test/java/org/opensearch/extensions/RegisterTransportActionsRequestTests.java → server/src/test/java/org/opensearch/extensions/action/RegisterTransportActionsRequestTests.java

@@ -6,15 +6,15 @@
  * compatible open source license.
  */
 
-package org.opensearch.extensions;
+package org.opensearch.extensions.action;
 
 import org.junit.Before;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.io.stream.StreamInput;
-import org.opensearch.extensions.action.RegisterTransportActionsRequest;
 import org.opensearch.test.OpenSearchTestCase;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Set;
 
 public class RegisterTransportActionsRequestTests extends OpenSearchTestCase {
@@ -37,6 +37,32 @@ public void testRegisterTransportActionsRequest() throws IOException {
     }
 
     public void testToString() {
-        assertEquals(originalRequest.toString(), "TransportActionsRequest{uniqueId=extension-uniqueId, actions=[testAction]}");
+        logger.info(originalRequest.toString());
+        assertEquals(
+            originalRequest.toString(),
+            "TransportActionsRequest{Identity=uniqueId: \"extension-uniqueId\"\n, actions=[testAction]}"
+        );
+    }
+
+    public void testNoIdentityRegisterTransportActionsRequest() {
+        String uniqueId = null;
+        // Expect exception as Extension Identity(uniqueId) is null
+        expectThrows(NullPointerException.class, () -> new RegisterTransportActionsRequest(uniqueId, Set.of()));
+    }
+
+    public void testNoTransportActionsRequest() {
+        String uniqueId = "extension-1234";
+        Set<String> expectedActions = null;
+        // Expect exception as paths are null
+        expectThrows(NullPointerException.class, () -> new RegisterTransportActionsRequest(uniqueId, expectedActions));
+    }
+
+    public void testEmptyTransportActionsRequest() {
+        String uniqueId = "extension-1234";
+        Set<String> expectedActions = Set.of();
+        RegisterTransportActionsRequest request = new RegisterTransportActionsRequest(uniqueId, expectedActions);
+
+        assertEquals(uniqueId, request.getUniqueId());
+        assertEquals(List.of(), request.getTransportActions());
     }
 }

server/src/test/java/org/opensearch/extensions/rest/RegisterRestActionsTests.java

@@ -60,7 +60,7 @@ public void testNoRestActionsRequest() {
         String uniqueId = "extension-1234";
         List<String> expected = null;
         List<String> expectedDeprecated = null;
-        // Expect exception as Extension Identity(uniqueId) is null
+        // Expect exception as paths are null
         expectThrows(NullPointerException.class, () -> new RegisterRestActionsRequest(uniqueId, expected, expectedDeprecated));
     }