[gRPC] How to correctly transmit error details to client with gRPC-JSON transcoding?

[Sayan751]

Discussed in #49179

^{Originally posted by Sayan751 July 3, 2023}
I have a gRPC service with JSON transcoding enabled. An endpoint of the service throws RpcException with same status code but different metadata. Examples:

throw new RpcException(new Status(StatusCode.InvalidArgument, "Whatever1"), new Metadata
{
    { "Code", Errors.Error1.ToString() }
});

throw new RpcException(new Status(StatusCode.InvalidArgument, "Whatever2"), new Metadata
{
    { "Code", Errors.Error2.ToString() }
});

Whoever, when I am making an HTTP call to the service, then I am getting the following:

{
  "code": 3,
  "message": "Whatever1",
  "details": []
}

I expected the trailers to appear in the details array. Am I missing something here? At the end, I need a way to differentiate between the two errors with the same status code. Is that possible?

[Sayan751]

Sorry for the tag @JamesNK, but can you please shade some light into this?

[adityamandaleeka]

cc @mgravell

[contione]

Is there a solution currently available?

[alrz]

It looks like the details field is left empty on error messages.

If the key "grpc-status-details-bin" is present in the trailers, the response should serialize that instead which will include the Details collection.

        static Google.Rpc.Status GetStatusDetailsFromTrailers(Metadata trailers)
        {
            const string GrpcStatusDetailsHeader = "grpc-status-details-bin";
            var statusDetails = trailers.Get(GrpcStatusDetailsHeader);
            if (statusDetails != null && statusDetails.IsBinary)
            {
                return Status.Parser.ParseFrom(statusDetails.ValueBytes);
            }

            return null;
        }

This is the key defined in dotnet-gax

[chris-crucible]

I am having the same issue and searching around led me here. Any chance of this making it in soon?