Updated RPC signature of service

[Robert Bielik]

Hi all,

As an update to a service we had, the signature of an RPC changed, from a non-streamed to a server side streaming RPC like so:

rpc StartProcess(ProcessData) returns (VoidMessage); // Version 1

and now it is:

rpc StartProcess(ProcessData) returns (stream Progress); // Version 2

Is there a way I can on the client side (C++ btw) check to see which signature of the RPC that the server implements ? I imagine that

if I call the RPC with the wrong signature, I would get a grpc::StatusCode::UNIMPLEMENTED ?

Regards

/Robert

[Carl Mastrangelo]

You can use server reflection to query what APIs it supposed.  Its a service that needs to be added to your server at the moment, but eventually it will be on by default.

[Eric Anderson]

On Mon, Dec 4, 2017 at 6:42 AM, Robert Bielik <robert...@gmail.com> wrote:

Is there a way I can on the client side (C++ btw) check to see which signature of the RPC that the server implements ? I imagine that

if I call the RPC with the wrong signature, I would get a grpc::StatusCode::UNIMPLEMENTED ?

Streaming uses the same basic format as non-streaming; it just has more messages. So if I assume how this looks based on message names, this actually looks mostly wire-compatible. The biggest problem is the return type changed. That may be fine too, assuming your VoidMessage has no fields like google.protobuf.Empty, and a no-fields-set Progress is semi-valid.