helper.go

/*
Copyright 2024.

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 helper

import (
	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/equality"
)

// CopyStatefulSetFields updates a target StatefulSet with the fields from a desired StatefulSet, returning true if an update is required.
func CopyStatefulSetFields(desired *appsv1.StatefulSet, target *appsv1.StatefulSet) bool {
	requireUpdate := false

	// copy `metadata.labels`
	for k, v := range target.Labels {
		if desired.Labels[k] != v {
			requireUpdate = true
		}
	}
	target.Labels = desired.Labels

	// copy `metadata.annotations`
	for k, v := range target.Annotations {
		if desired.Annotations[k] != v {
			requireUpdate = true
		}
	}
	target.Annotations = desired.Annotations

	// copy `spec.replicas`
	if *desired.Spec.Replicas != *target.Spec.Replicas {
		*target.Spec.Replicas = *desired.Spec.Replicas
		requireUpdate = true
	}

	// copy `spec.selector`
	//
	// TODO: confirm if StatefulSets support updates to the selector
	//       if not, we might need to recreate the StatefulSet
	//
	if !equality.Semantic.DeepEqual(target.Spec.Selector, desired.Spec.Selector) {
		target.Spec.Selector = desired.Spec.Selector
		requireUpdate = true
	}

	// copy `spec.template`
	//
	// TODO: confirm if there is a problem with doing the update at the `spec.template` level
	//       or if only `spec.template.spec` should be updated
	//
	if !equality.Semantic.DeepEqual(target.Spec.Template, desired.Spec.Template) {
		target.Spec.Template = desired.Spec.Template
		requireUpdate = true
	}

	return requireUpdate
}

// CopyServiceFields updates a target Service with the fields from a desired Service, returning true if an update is required.
func CopyServiceFields(desired *corev1.Service, target *corev1.Service) bool {
	requireUpdate := false

	// copy `metadata.labels`
	for k, v := range target.Labels {
		if desired.Labels[k] != v {
			requireUpdate = true
		}
	}
	target.Labels = desired.Labels

	// copy `metadata.annotations`
	for k, v := range target.Annotations {
		if desired.Annotations[k] != v {
			requireUpdate = true
		}
	}
	target.Annotations = desired.Annotations

	// NOTE: we don't copy the entire `spec` because we can't overwrite the `spec.clusterIp` and similar fields

	// copy `spec.ports`
	if !equality.Semantic.DeepEqual(target.Spec.Ports, desired.Spec.Ports) {
		target.Spec.Ports = desired.Spec.Ports
		requireUpdate = true
	}

	// copy `spec.selector`
	if !equality.Semantic.DeepEqual(target.Spec.Selector, desired.Spec.Selector) {
		target.Spec.Selector = desired.Spec.Selector
		requireUpdate = true
	}

	// copy `spec.type`
	if target.Spec.Type != desired.Spec.Type {
		target.Spec.Type = desired.Spec.Type
		requireUpdate = true
	}

	return requireUpdate
}