In the third section of the example stringsvc application the guide tells the user that the following snippet is the correct definition for a proxied version of the Uppercase service:

func (mw proxymw) Uppercase(s string) (string, error) {
	response, err := mw.uppercase(uppercaseRequest{S: s})
	if err != nil {
		return "", err
	}
	resp := response.(uppercaseResponse)
	if resp.Err != "" {
		return resp.V, errors.New(resp.Err)
	}
	return resp.V, nil
}

Since mw.uppercase returns an Endpoint and Endpoints must recieve two args this cannot be correct.

Meanwhile, the code in GitHub has this definition:

func (mw proxymw) Uppercase(s string) (string, error) {
	response, err := mw.uppercase(mw.ctx, uppercaseRequest{S: s})
	if err != nil {
		return "", err
	}

	resp := response.(uppercaseResponse)
	if resp.Err != "" {
		return resp.V, errors.New(resp.Err)
	}
	return resp.V, nil
}

The example code in the guide should likely include ctx as part of the struct and ctx should be included in the response variable creation.

There was recently some work done to remove ctx from the earlier examples in stringsvc1. Perhaps there is already work being done in this area?

Sources:

http://gokit.io/examples/stringsvc.html#calling-other-services
https://github.com/go-kit/kit/blob/master/examples/stringsvc3/proxying.go#L69-L90