Default ingress-class can not be overridden

set-ingress-class.go

package main

import (
	"flag"
	"fmt"
	"os"

	"github.com/spf13/pflag"
)

func main() {
	flags := pflag.NewFlagSet("", pflag.ExitOnError)
	ingressClass := flags.String("ingress-class", "",
		`Name of the ingress class to route through this controller.`)
	flags.AddGoFlagSet(flag.CommandLine)

	ingressClassFoo := flags.Lookup("ingress-class")
	// Set default value before Parse
	if ingressClassFoo != nil {
		ingressClassFoo.Value.Set("haproxy")
		ingressClassFoo.DefValue = "haproxy"
	}

	// Perform Parse
	flags.Parse(os.Args)

	// change flag value after Parse
	ic, _ := flags.GetString("ingress-class")
	if ic == "" {
		flags.Set("ingress-class", "haproxy")
	}

	fmt.Printf("Ingress class: %s\n", *ingressClass)
}

//$ go run main.go
//Ingress class: haproxy
//$ go run main.go --ingress-class=Foo
//Ingress class: Foo