Get rid of "ServiceBackend" in Kubernetes Routegroups

[szuecs]

There is a hacked backend, that we sooner or later should get rid of:

// adding Kubernetes specific backend types here. To be discussed.
// The main reason is to differentiate between service and external, in a way
// where we can also use the current global option to decide whether the service
// should then be converted to LB. Or shall we expect the route group already
// contain the pod endpoints, and ignore the global option for skipper?
// --> As CRD we have to lookup endpoints ourselves, maybe via kube.go
const (
	ServiceBackend = eskip.LBBackend + 1 + iota
)

Normally in eskip we do not have it and when we introduced <forward> backend we stumbled in our cluster about the validation webhook that denied this backend because somehow eskip.LBBackend + 1 mapped to eskip.ForwardBackend...

[AlexanderYastrebov]

🙈 🤣

const ServiceBackend = -1

[AlexanderYastrebov]

I guess we can add unexported isService bool here

skipper/dataclients/kubernetes/definitions/routegroups.go

Line 93 in 589f118

parseError error

and return it from here

skipper/dataclients/kubernetes/definitions/routegroups.go

Lines 288 to 295 in 589f118

	func backendTypeFromString(s string) (eskip.BackendType, error) {
	switch s {
	case "", "service":
	return ServiceBackend, nil
	default:
	return eskip.BackendTypeFromString(s)
	}
	}