golang-fluent-pattern-middleware-example.go

package main

import "fmt"

func main() {
    var sendEmail emailAction = func(payload string) {
        fmt.Printf("sending email: %v\n", payload)
    }

    action := sendEmail.
        authenticate("username:password").
        connectToServer("email-server:443")

    action("my email")
}

type emailAction func(payload string)

func (a emailAction) connectToServer(server string) emailAction {
    return func(payload string) {
        fmt.Printf("connecting to server: %v\n", server)
        a(payload)
    }
}

func (a emailAction) authenticate(cred string) emailAction {
    return func(payload string) {
        fmt.Printf("authenticating with cred: %v\n", cred)
        a(payload)
    }
}