nodeselector.go-ff81dbd79b18e66d8bf936ae7f7f867e2427d8d07d4e17c7be3bd67319bd235e

// PUBLISH-CODE
/*
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 selector

import (
	"fmt"

	core "go.tectonic.network/lib/k8s/imp/api/core/v1"
	metav1 "go.tectonic.network/lib/k8s/meta/v1"
)

// The code is taken from github.com/kubernetes/component-helpers/scheduling/corev1/nodeaffinity
// and modified.

// PodMatchesNodeAffinity checks whether the node labels and fields match the node selector, nil or empty term matches no objects.
//
// from GetRequiredNodeAffinity
func PodMatchesNodeAffinity(pod *core.Pod, node *core.Node) (bool, error) {
	if node == nil {
		return false, nil
	}

	for label, value := range pod.Spec.NodeSelector {
		match, err := selectorMatchesLabels(label, equals, []string{value}, node.Labels)
		if err != nil {
			return false, err
		}
		if !match {
			return false, nil
		}
	}

	if pod.Spec.Affinity != nil &&
		pod.Spec.Affinity.NodeAffinity != nil &&
		pod.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution != nil {
		return nodeSelectorsMatchesNodeAffinity(*pod.Spec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution, node)
	}

	return true, nil
}

// from LazyErrorNodeSelector.Match
func nodeSelectorsMatchesNodeAffinity(nodeSelector core.NodeSelector, node *core.Node) (bool, error) {
	if node == nil {
		return false, nil
	}

	nodeFields := map[string]string{}
	if len(node.Name) > 0 {
		nodeFields[metav1.ObjectNameField] = node.Name
	}

	for _, term := range nodeSelector.NodeSelectorTerms {
		if len(term.MatchExpressions) == 0 && len(term.MatchFields) == 0 { // empty node selector
			continue
		}
		match, err := nodeSelectorTermMatchesNodeAffinity(term, node.Labels, nodeFields)
		if err != nil {
			return false, err
		}
		if match {
			return true, nil
		}
	}
	return false, nil
}

// from newNodeSelectorTerm
func nodeSelectorTermMatchesNodeAffinity(nodeSelectorTerm core.NodeSelectorTerm, nodeLabels, nodeFields map[string]string) (bool, error) {
	// from nodeSelectorRequirementsAsSelector
	for _, term := range nodeSelectorTerm.MatchExpressions {
		var op operator
		switch term.Operator {
		case core.NodeSelectorOpIn:
			op = in
		case core.NodeSelectorOpNotIn:
			op = notIn
		case core.NodeSelectorOpExists:
			op = exists
		case core.NodeSelectorOpDoesNotExist:
			op = doesNotExist
		case core.NodeSelectorOpGt:
			op = greaterThan
		case core.NodeSelectorOpLt:
			op = lessThan
		default:
			return false, fmt.Errorf("%q is not a valid node selector operator", term.Operator)
		}

		if match, err := selectorMatchesLabels(term.Key, op, term.Values, nodeLabels); !match {
			return false, err
		}
	}

	// from nodeSelectorRequirementsAsFieldSelector
	for _, term := range nodeSelectorTerm.MatchFields {
		switch term.Operator {
		case core.NodeSelectorOpIn:
			if len(term.Values) != 1 {
				return false, fmt.Errorf("invalid value %v: must have one element", term.Values)
			}
			if nodeFields[term.Key] != term.Values[0] {
				return false, nil
			}
		case core.NodeSelectorOpNotIn:
			if len(term.Values) != 1 {
				return false, fmt.Errorf("invalid value %v: must have one element", term.Values)
			}
			if nodeFields[term.Key] == term.Values[0] {
				return false, nil
			}
		default:
			return false, fmt.Errorf("operator %s not supported", term.Operator)
		}
	}

	return true, nil
}