Learning Functional Programming in Go

The decorator/decorator.go file

Let's look at our decorator.go implementation. It's in the 02_decorator directory, and the package name is decorator:

package decoratorimport (       "log"       "net/http"       "sync/atomic"       "time")type Client interface {       Do(*http.Request) (*http.Response, error)}// ClientFunc is a function type that implements the client interface.type ClientFunc func(*http.Request) (*http.Response, error)func (f ClientFunc) Do(r *http.Request) (*http.Response, error) {       return f(r)}

The ClientFunc function is a function type that implements the Client interface.

We also define two additional methods that act as the getter and setter for the ratelimitDuration value:

var ratelimitDuration time.Durationfunc (f ClientFunc) SetRatelimit(duration ...