Client does not report correct error codes per the spec for HTTP status code mapping

[jhump]

A well-formed gRPC response always has an HTTP status code of “200 OK”. The gRPC docs specify a table for mapping other HTTP status codes to gRPC error codes: https://github.com/grpc/grpc/blob/master/doc/http-grpc-status-mapping.md.

The client in this package varies from the above table. Specifically, here are HTTP status codes which produce an unexpected error code:

HTTP status code	Expected error code	Actual error code
400 Bad Request	internal	unknown
404 Not Found	unimplemented	unknown
409 Conflict	unknown	aborted
412 Precondition Failed	unknown	failed_precondition
429 Too Many Requests	unavailable	unknown
502 Bad Gateway	unavailable	unknown
504 Gateway Timeout	unavailable	unknown

[sampajano]

@jhump Thanks a lot for reporting! Will take a look soon!

[shoebilyas123]

Hi Team,
I would like to work on this issue

[sampajano]

@shoebilyas123 Thanks for your interest! You're most welcome to help contribute to this issue!

[shoebilyas123]

Thank you. I will start working on it then <3

[sampajano]

Thank you. I will start working on it then <3

Ok! Thank you very much! 😊

One request: if you could start small, especially on some more controversial changes, it might be easier for us to get aligned and save you some time before you invest more into further associated changes! Thanks! 😃