Go - Write sample code for setting and reading error details

[jcanizales]

Go issue for grpc/grpc#4543

[kelseyhightower]

Is this something I can take a shot at? I've been playing with grpc and wonder if the following example would work:

Creating a grpc error:
https://github.com/kelseyhightower/grpc-hello-service/blob/master/hello-server/main.go#L74

[jcanizales]

You're very very welcome to give it a shot!

More specifically, we'd want a sample that shows sending an error with metadata attached in the HTTP/2 trailers, as well as reading that metadata from the client. That being the recommended way to specify error details when the error code isn't enough to make the error actionable.

[kelseyhightower]

Fixed in #506. @jcanizales PTAL

[c4milo]

@dfawley, shouldn't this be closed since it seems addressed by #506?

[dfawley]

That PR was not merged.. A different sample is necessary with the recentish changes to status.

(And now with the helpers added in #1358.)

[enocom]

In #506, the APIs on display were grpc.SetTrailer on the server, and grpc.Trailer on the client.

With the helpers added in #1358, it seems the preferred way to transfer error details is status.WithDetails on the server and status.Details on the client.

Is that the gist of the issue here?

[dfawley]

@enocom,

Is that the gist of the issue here?

Correct! Trailers are still useful. However, for detailed error information, status.WithDetails should be used instead. (Trailers can be used to transmit additional data at the end of an RPC even on success.)