func CompliantLabelString(s string) string {
	s = strings.ToLower(s)
	reg, _ := regexp.Compile("[^a-z0-9_-]+")
	s = reg.ReplaceAllString(s, "-")
	return s
}
CompliantLabelString - convert to GCP compliant string
https://cloud.google.com/resource-manager/docs/creating-managing-labels
package gcp
import (
	"cloud.google.com/go/compute/metadata"
	"flag"
	"google.golang.org/api/googleapi"
	"net/http"
	"regexp"
	"sigs.k8s.io/controller-reconciler/pkg/reconciler"
	"strings"
)
var (
	projectID, zone string
)
func init() {
	flag.StringVar(&projectID, "gcpproject", "",
		"GCP Project ID. Required for outside cluster.")
	flag.StringVar(&zone, "gcpzone", "",
		"GCP Zone. Required for outside cluster.")
}