/*
Copyright 2020 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package util

import (
	"context"

	coordinationv1 "k8s.io/api/coordination/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	clientset "k8s.io/client-go/kubernetes"

	"k8s.io/klog/v2"
)

// SetNodeOwnerFunc helps construct a newLeasePostProcessFunc which sets
// a node OwnerReference to the given lease object
func SetNodeOwnerFunc(c clientset.Interface, nodeName string) func(lease *coordinationv1.Lease) error {
	return func(lease *coordinationv1.Lease) error {
		// Setting owner reference needs node's UID. Note that it is different from
		// kubelet.nodeRef.UID. When lease is initially created, it is possible that
		// the connection between master and node is not ready yet. So try to set
		// owner reference every time when renewing the lease, until successful.
		if len(lease.OwnerReferences) == 0 {
			if node, err := c.CoreV1().Nodes().Get(context.TODO(), nodeName, metav1.GetOptions{}); err == nil {
				lease.OwnerReferences = []metav1.OwnerReference{
					{
						APIVersion: corev1.SchemeGroupVersion.WithKind("Node").Version,
						Kind:       corev1.SchemeGroupVersion.WithKind("Node").Kind,
						Name:       nodeName,
						UID:        node.UID,
					},
				}
			} else {
				klog.Errorf("failed to get node %q when trying to set owner ref to the node lease: %v", nodeName, err)
				return err
			}
		}
		return nil
	}
}
