Expose SETTING_GRPC_MAX_MSG_SIZE to settings service (#18910) (#18954)

(cherry picked from commit bf5b43d)

Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: opensearch-trigger-bot[bot]

CHANGELOG.md

@@ -117,6 +117,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Close IndexFieldDataService asynchronously ([#18888](https://github.com/opensearch-project/OpenSearch/pull/18888))
 - Fix query string regex queries incorrectly swallowing TooComplexToDeterminizeException ([#18883](https://github.com/opensearch-project/OpenSearch/pull/18883))
 - Fix socks5 user password settings for Azure repo ([#18904](https://github.com/opensearch-project/OpenSearch/pull/18904))
+- Fix gRPC transport SETTING_GRPC_MAX_MSG_SIZE setting not exposed to users ([#18910](https://github.com/opensearch-project/OpenSearch/pull/18910))
 - Reset isPipelineResolved to false to resolve the system ingest pipeline again. ([#18911](https://github.com/opensearch-project/OpenSearch/pull/18911))
 
 ### Security

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

@@ -52,6 +52,7 @@
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_MAX_CONCURRENT_CONNECTION_CALLS;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_MAX_CONNECTION_AGE;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_MAX_CONNECTION_IDLE;
+import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_MAX_MSG_SIZE;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_PORT;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_PUBLISH_HOST;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_PUBLISH_PORT;
@@ -220,6 +221,7 @@ public List<Setting<?>> getSettings() {
             SETTING_GRPC_BIND_HOST,
             SETTING_GRPC_WORKER_COUNT,
             SETTING_GRPC_MAX_CONCURRENT_CONNECTION_CALLS,
+            SETTING_GRPC_MAX_MSG_SIZE,
             SETTING_GRPC_MAX_CONNECTION_AGE,
             SETTING_GRPC_MAX_CONNECTION_IDLE,
             SETTING_GRPC_KEEPALIVE_TIMEOUT

modules/transport-grpc/src/test/java/org/opensearch/transport/grpc/GrpcPluginTests.java

@@ -41,6 +41,7 @@
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_MAX_CONCURRENT_CONNECTION_CALLS;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_MAX_CONNECTION_AGE;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_MAX_CONNECTION_IDLE;
+import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_MAX_MSG_SIZE;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_PORT;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_PUBLISH_HOST;
 import static org.opensearch.transport.grpc.Netty4GrpcServerTransport.SETTING_GRPC_PUBLISH_PORT;
@@ -115,12 +116,13 @@ public void testGetSettings() {
             "SETTING_GRPC_MAX_CONCURRENT_CONNECTION_CALLS should be included",
             settings.contains(SETTING_GRPC_MAX_CONCURRENT_CONNECTION_CALLS)
         );
+        assertTrue("SETTING_GRPC_MAX_MSG_SIZE should be included", settings.contains(SETTING_GRPC_MAX_MSG_SIZE));
         assertTrue("SETTING_GRPC_MAX_CONNECTION_AGE should be included", settings.contains(SETTING_GRPC_MAX_CONNECTION_AGE));
         assertTrue("SETTING_GRPC_MAX_CONNECTION_IDLE should be included", settings.contains(SETTING_GRPC_MAX_CONNECTION_IDLE));
         assertTrue("SETTING_GRPC_KEEPALIVE_TIMEOUT should be included", settings.contains(SETTING_GRPC_KEEPALIVE_TIMEOUT));
 
         // Verify the number of settings
-        assertEquals("Should return 11 settings", 11, settings.size());
+        assertEquals("Should return 12 settings", 12, settings.size());
     }
 
     public void testGetQueryUtilsBeforeCreateComponents() {