selection.go

package storage

import corev1 "github.com/rancher/opni/pkg/apis/core/v1"

type SelectorPredicate[T corev1.IdLabelReader] func(T) bool

func NewSelectorPredicate[T corev1.IdLabelReader](s *corev1.ClusterSelector) SelectorPredicate[T] {
	emptyLabelSelector := s.LabelSelector.IsEmpty()
	if emptyLabelSelector && len(s.ClusterIDs) == 0 {
		switch {
		case s.MatchOptions&corev1.MatchOptions_EmptySelectorMatchesNone != 0:
			return func(T) bool { return false }
		default:
			return func(T) bool { return true }
		}
	}
	idSet := map[string]struct{}{}
	for _, id := range s.ClusterIDs {
		idSet[id] = struct{}{}
	}
	return func(c T) bool {
		id := c.GetId()
		if _, ok := idSet[id]; ok {
			return true
		}
		if emptyLabelSelector {
			return false
		}
		return labelSelectorMatches(s.LabelSelector, c.GetLabels())
	}
}

func labelSelectorMatches(selector *corev1.LabelSelector, labels map[string]string) bool {
	for key, value := range selector.MatchLabels {
		if labels[key] != value {
			return false
		}
	}
	for _, req := range selector.MatchExpressions {
		switch corev1.LabelSelectorOperator(req.Operator) {
		case corev1.LabelSelectorOpIn:
			ok := false
			for _, value := range req.Values {
				if labels[req.Key] == value {
					ok = true
					break
				}
			}
			if !ok {
				return false
			}
		case corev1.LabelSelectorOpNotIn:
			v, ok := labels[req.Key]
			if !ok {
				return false
			}
			for _, value := range req.Values {
				if v == value {
					return false
				}
			}
			return true
		case corev1.LabelSelectorOpExists:
			if _, ok := labels[req.Key]; !ok {
				return false
			}
		case corev1.LabelSelectorOpDoesNotExist:
			if _, ok := labels[req.Key]; ok {
				return false
			}
		}
	}
	return true
}