[GRPC] Bulk optimization and fixes

CHANGELOG.md

@@ -63,6 +63,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add S3Repository.LEGACY_MD5_CHECKSUM_CALCULATION to list of repository-s3 settings ([#19788](https://github.com/opensearch-project/OpenSearch/pull/19788))
 - Fix NullPointerException when restoring remote snapshot with missing shard size information ([#19684](https://github.com/opensearch-project/OpenSearch/pull/19684))
 - Fix NPE of ScriptScoreQuery ([#19650](https://github.com/opensearch-project/OpenSearch/pull/19650))
+- Fix GRPC Bulk ([#19937](https://github.com/opensearch-project/OpenSearch/pull/19937))
 
 ### Dependencies
 - Update to Gradle 9.2 ([#19575](https://github.com/opensearch-project/OpenSearch/pull/19575)) ([#19856](https://github.com/opensearch-project/OpenSearch/pull/19856))

modules/transport-grpc/src/main/java/org/opensearch/transport/grpc/GrpcPlugin.java

@@ -259,7 +259,6 @@ public Map<String, Supplier<AuxTransport>> getSecureAuxTransports(
         if (client == null || queryRegistry == null) {
             throw new RuntimeException("createComponents must be called first to initialize server provided resources.");
         }
-
         return Collections.singletonMap(GRPC_SECURE_TRANSPORT_SETTING_KEY, () -> {
             List<BindableService> grpcServices = new ArrayList<>(
                 List.of(new DocumentServiceImpl(client), new SearchServiceImpl(client, queryUtils))

modules/transport-grpc/src/main/java/org/opensearch/transport/grpc/proto/request/common/FetchSourceContextProtoUtils.java

@@ -38,7 +38,7 @@ private FetchSourceContextProtoUtils() {
      * @return A FetchSourceContext object based on the request parameters, or null if no source parameters are provided
      */
     public static FetchSourceContext parseFromProtoRequest(org.opensearch.protobufs.BulkRequest request) {
-        Boolean fetchSource = true;
+        Boolean fetchSource = null;
         String[] sourceExcludes = null;
         String[] sourceIncludes = null;
 

modules/transport-grpc/src/main/java/org/opensearch/transport/grpc/proto/request/document/bulk/BulkRequestProtoUtils.java

@@ -36,6 +36,12 @@ private BulkRequestProtoUtils() {
      * Similar to {@link RestBulkAction#prepareRequest(RestRequest, NodeClient)}
      * Please ensure to keep both implementations consistent.
      *
+     * Note: Unlike REST API, gRPC does not enforce the allowExplicitIndex security setting.
+     * In REST, this setting provides network-level security by allowing proxies to filter
+     * requests based on URL paths. In gRPC, both default_index and x_index are in the
+     * request body, making this check ineffective for network-level security.
+     * For gRPC security, use mTLS, gRPC interceptors, or service mesh policies instead.
+     *
      * @param request the request to execute
      * @return a future of the bulk action that was executed
      */

modules/transport-grpc/src/test/java/org/opensearch/transport/grpc/proto/request/common/FetchSourceContextProtoUtilsTests.java

@@ -109,12 +109,9 @@ public void testParseFromProtoRequestWithNoSourceParams() {
         FetchSourceContext context = FetchSourceContextProtoUtils.parseFromProtoRequest(request);
 
         // Verify the result
-        // The implementation returns a default FetchSourceContext with fetchSource=true
-        // and empty includes/excludes arrays when no source parameters are provided
-        assertNotNull("Context should not be null", context);
-        assertTrue("fetchSource should be true", context.fetchSource());
-        assertArrayEquals("includes should be empty", Strings.EMPTY_ARRAY, context.includes());
-        assertArrayEquals("excludes should be empty", Strings.EMPTY_ARRAY, context.excludes());
+        // When no source parameters are provided, should return null to match REST API behavior
+        // This prevents the "get" field from being returned in update/upsert responses
+        assertNull("Context should be null when no source parameters provided", context);
     }
 
     public void testFromProtoWithFetch() {