feat: Introduce a Generic ResourceReconciler and a generic BaseWorkload to de-duplicate a lot of code

internal/pkg/workload/base.go

@@ -0,0 +1,188 @@
+package workload
+
+import (
+	"context"
+
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+// PodTemplateAccessor provides access to a workload's pod template.
+// Each workload type implements this to provide access to its specific template location.
+type PodTemplateAccessor interface {
+	// GetPodTemplateSpec returns a pointer to the pod template spec.
+	// Returns nil if the workload doesn't have a pod template
+	GetPodTemplateSpec() *corev1.PodTemplateSpec
+
+	// GetObjectMeta returns the workload's object metadata.
+	GetObjectMeta() *metav1.ObjectMeta
+}
+
+// BaseWorkload provides common functionality for all workload types.
+// It uses composition with a PodTemplateAccessor to access type-specific fields.
+type BaseWorkload[T client.Object] struct {
+	object   T
+	original T
+	accessor PodTemplateAccessor
+	kind     Kind
+}
+
+// NewBaseWorkload creates a new BaseWorkload with the given object and accessor.
+func NewBaseWorkload[T client.Object](obj T, original T, accessor PodTemplateAccessor, kind Kind) *BaseWorkload[T] {
+	return &BaseWorkload[T]{
+		object:   obj,
+		original: original,
+		accessor: accessor,
+		kind:     kind,
+	}
+}
+
+func (b *BaseWorkload[T]) Kind() Kind {
+	return b.kind
+}
+
+func (b *BaseWorkload[T]) GetObject() client.Object {
+	return b.object
+}
+
+func (b *BaseWorkload[T]) GetName() string {
+	return b.accessor.GetObjectMeta().Name
+}
+
+func (b *BaseWorkload[T]) GetNamespace() string {
+	return b.accessor.GetObjectMeta().Namespace
+}
+
+func (b *BaseWorkload[T]) GetAnnotations() map[string]string {
+	return b.accessor.GetObjectMeta().Annotations
+}
+
+func (b *BaseWorkload[T]) GetPodTemplateAnnotations() map[string]string {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return nil
+	}
+	if template.Annotations == nil {
+		template.Annotations = make(map[string]string)
+	}
+	return template.Annotations
+}
+
+func (b *BaseWorkload[T]) SetPodTemplateAnnotation(key, value string) {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return
+	}
+	if template.Annotations == nil {
+		template.Annotations = make(map[string]string)
+	}
+	template.Annotations[key] = value
+}
+
+func (b *BaseWorkload[T]) GetContainers() []corev1.Container {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return nil
+	}
+	return template.Spec.Containers
+}
+
+func (b *BaseWorkload[T]) SetContainers(containers []corev1.Container) {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return
+	}
+	template.Spec.Containers = containers
+}
+
+func (b *BaseWorkload[T]) GetInitContainers() []corev1.Container {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return nil
+	}
+	return template.Spec.InitContainers
+}
+
+func (b *BaseWorkload[T]) SetInitContainers(containers []corev1.Container) {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return
+	}
+	template.Spec.InitContainers = containers
+}
+
+func (b *BaseWorkload[T]) GetVolumes() []corev1.Volume {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return nil
+	}
+	return template.Spec.Volumes
+}
+
+func (b *BaseWorkload[T]) GetEnvFromSources() []corev1.EnvFromSource {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return nil
+	}
+	var sources []corev1.EnvFromSource
+	for _, container := range template.Spec.Containers {
+		sources = append(sources, container.EnvFrom...)
+	}
+	for _, container := range template.Spec.InitContainers {
+		sources = append(sources, container.EnvFrom...)
+	}
+	return sources
+}
+
+func (b *BaseWorkload[T]) UsesConfigMap(name string) bool {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return false
+	}
+	return SpecUsesConfigMap(&template.Spec, name)
+}
+
+func (b *BaseWorkload[T]) UsesSecret(name string) bool {
+	template := b.accessor.GetPodTemplateSpec()
+	if template == nil {
+		return false
+	}
+	return SpecUsesSecret(&template.Spec, name)
+}
+
+func (b *BaseWorkload[T]) GetOwnerReferences() []metav1.OwnerReference {
+	return b.accessor.GetObjectMeta().OwnerReferences
+}
+
+// Update performs a strategic merge patch update.
+func (b *BaseWorkload[T]) Update(ctx context.Context, c client.Client) error {
+	return c.Patch(ctx, b.object, client.StrategicMergeFrom(b.original), client.FieldOwner(FieldManager))
+}
+
+// ResetOriginal resets the original state to the current object state.
+func (b *BaseWorkload[T]) ResetOriginal() {
+	b.original = b.object.DeepCopyObject().(T)
+}
+
+// UpdateStrategy returns the default patch strategy.
+// Workloads with special update logic should override this.
+func (b *BaseWorkload[T]) UpdateStrategy() UpdateStrategy {
+	return UpdateStrategyPatch
+}
+
+// PerformSpecialUpdate returns false for standard workloads.
+// Workloads with special update logic should override this.
+func (b *BaseWorkload[T]) PerformSpecialUpdate(ctx context.Context, c client.Client) (bool, error) {
+	return false, nil
+}
+
+// Object returns the underlying Kubernetes object.
+func (b *BaseWorkload[T]) Object() T {
+	return b.object
+}
+
+// Original returns the original state of the object.
+func (b *BaseWorkload[T]) Original() T {
+	return b.original
+}