Question: purpose of the `Grpc.Status.t` returned with the `Ok` case.

[clembu]

Hello everyone. I'm wondering why there's a status tupled with the rpc response, as a return to Client.call.

All the examples end up matching the result with

match response with
| Ok (response, _ok) -> ...
| Error error -> ...

As there are no examples showing a use case for this status, and all existing examples end up ignoring it, I am left wondering why it is given at all. Are there any cases where it is not the OK status? If so, which values can it be?

[quernd]

Thanks for bringing this up! These are gRPC specific status codes. It is not necessarily the OK status, and it's up to you to handle it or not.

• This is the list of numerical status codes: https://github.com/grpc/grpc/blob/18be986e3b80061fae5576d228011f85d0d296a0/doc/statuscodes.md
• and this is the mapping of the numerical codes to OCaml values: https://dialohq.github.io/ocaml-grpc/grpc/Grpc/Status/index.html

You're right, it would be good not to ignore this code in the examples. Feel free to modify the examples and open a PR, otherwise we'll get to it some time soon.

[tmcgilchrist]

An interesting example to add would be support for the gRPC health check API and implement a scenario like pausing calling a service when the health check stops responding then resuming when it is healthy again. I made an earlier start on it here https://github.com/tmcgilchrist/ocaml-grpc/tree/grpc_health_check with a view to implementing this example from Rust https://github.com/hyperium/tonic/tree/master/examples/src/health