Plugin error handling

[zosocanuck]

Hi,

I'm testing a plugin prototype (based on notation-azure-kv) that will implement signature generator however when it comes to error handling I seem to be only obtaining the following generic error:

Error: describe-key command failed: xyz-plugin: ERROR: failed to decode json response: plugin not compliant

In cmd/xyz-plugin main.go I have:

if err := app.Run(os.Args); err != nil {
		var reer plugin.RequestError
		if !errors.As(err, &reer) {
			err = plugin.RequestError{
				Code: plugin.ErrorCodeGeneric,
				Err:  err,
			}
		}
		data, _ := json.Marshal(err)
		os.Stderr.Write(data)
		os.Exit(1)
	}

Within the actual runDescribeKey I'm returning a plugin.RequestError per the spec:

if err != nil {
			return nil, plugin.RequestError{
				Code: plugin.ErrorCodeValidation,
				Err:  errors.New("custom error message goes here: " + err.Error()),
			}
		}

Seems like the plugin handler in notation-go is not correctly handling the returned error?

[sajayantony]

• @shizhMSFT @priteshbandi might be able to comment on this.

[JeyJeyGao]

Hi Ivan @zosocanuck , notation-go package has been refactored. Looks like you were using plugin.RequestError which is the old version. After refactoring, it should be proto.RequestError, so could you try the notation-go RC.1 again? Please let us know if you still have issues.

Please try:

go get github.com/notaryproject/[email protected]
go mod tidy

then replace plugin.RequestError with proto.RequestError and try again.
You should also use Notation CLI RC.1 to test your plugin.

[zosocanuck]

@JeyJeyGao Yes I'm using the latest RC.1 and turns out I was unexpectedly sending log information via os.Stdout, which was causing the issue, and hence would explain the error about the plugin not being compliant.