ssa: rewrite Unstructured normalization logic

Signed-off-by: Hidde Beydals <[email protected]>

ssa/normalize.go

@@ -0,0 +1,150 @@
+/*
+Copyright 2023 The Flux 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 ssa
+
+import (
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/kubernetes/scheme"
+)
+
+// FromUnstructured converts an Unstructured object into a typed Kubernetes
+// resource. It only works for API types registered with the default client-go
+// scheme.
+func FromUnstructured(object *unstructured.Unstructured) (metav1.Object, error) {
+	return FromUnstructuredWithScheme(object, scheme.Scheme)
+}
+
+// FromUnstructuredWithScheme converts an Unstructured object into a typed
+// Kubernetes resource. It only works for API types registered with the given
+// scheme.
+func FromUnstructuredWithScheme(object *unstructured.Unstructured, scheme *runtime.Scheme) (metav1.Object, error) {
+	typedObject, err := scheme.New(object.GroupVersionKind())
+	if err != nil {
+		return nil, err
+	}
+
+	metaObject, ok := typedObject.(metav1.Object)
+	if !ok {
+		return nil, err
+	}
+
+	if err = runtime.DefaultUnstructuredConverter.FromUnstructured(object.Object, metaObject); err != nil {
+		return nil, err
+	}
+	return metaObject, nil
+}
+
+// ToUnstructured converts a typed Kubernetes resource into the Unstructured
+// equivalent.
+func ToUnstructured(object metav1.Object) (*unstructured.Unstructured, error) {
+	u, err := runtime.DefaultUnstructuredConverter.ToUnstructured(object)
+	if err != nil {
+		return nil, err
+	}
+	return &unstructured.Unstructured{Object: u}, nil
+}
+
+// NormalizeUnstructured normalizes an Unstructured object by converting it to
+// a typed Kubernetes resource, normalizing it, and then converting it back to
+// an Unstructured object. It only works for API types registered with the
+// default client-go scheme. If the conversion fails, only certain standard
+// fields are removed.
+func NormalizeUnstructured(object *unstructured.Unstructured) error {
+	return NormalizeUnstructuredWithScheme(object, scheme.Scheme)
+}
+
+// NormalizeUnstructuredWithScheme normalizes an Unstructured object by
+// converting it to a typed Kubernetes resource, normalizing it, and then
+// converting it back to an Unstructured object. It only works for API types
+// registered with the given scheme. If the conversion fails, only certain
+// standard fields are removed.
+func NormalizeUnstructuredWithScheme(object *unstructured.Unstructured, scheme *runtime.Scheme) error {
+	if typedObject, err := FromUnstructuredWithScheme(object, scheme); err == nil {
+		switch o := typedObject.(type) {
+		case *appsv1.Deployment:
+			normalizePodProtoDefault(&o.Spec.Template.Spec)
+		case *appsv1.StatefulSet:
+			normalizePodProtoDefault(&o.Spec.Template.Spec)
+		case *appsv1.DaemonSet:
+			normalizePodProtoDefault(&o.Spec.Template.Spec)
+		case *appsv1.ReplicaSet:
+			normalizePodProtoDefault(&o.Spec.Template.Spec)
+		case *corev1.Service:
+			normalizeServiceProtoDefault(&o.Spec)
+		case *corev1.Secret:
+			normalizeSecret(o)
+		}
+
+		normalizedObject, err := ToUnstructured(typedObject)
+		if err != nil {
+			return err
+		}
+		object.Object = normalizedObject.Object
+	}
+
+	// Remove fields that are not supposed to be applied.
+	unstructured.RemoveNestedField(object.Object, "metadata", "creationTimestamp")
+
+	// To ensure kstatus continues to work with CRDs, we need to keep the
+	// status field for CRDs.
+	if !IsCRD(object) {
+		unstructured.RemoveNestedField(object.Object, "status")
+	}
+
+	return nil
+}
+
+// normalizeServiceProtoDefault sets the default protocol for ports in a
+// ServiceSpec.
+// xref: https://github.com/kubernetes/kubernetes/pull/98576
+func normalizeServiceProtoDefault(spec *corev1.ServiceSpec) {
+	for i, port := range spec.Ports {
+		if len(port.Protocol) == 0 {
+			spec.Ports[i].Protocol = corev1.ProtocolTCP
+		}
+	}
+}
+
+// normalizePodProtoDefault sets the default protocol for ports in a PodSpec.
+// xref: https://github.com/kubernetes-sigs/structured-merge-diff/issues/130
+func normalizePodProtoDefault(spec *corev1.PodSpec) {
+	for _, c := range spec.Containers {
+		for i, port := range c.Ports {
+			if len(port.Protocol) == 0 {
+				c.Ports[i].Protocol = corev1.ProtocolTCP
+			}
+		}
+	}
+}
+
+// normalizeSecret converts a Secret's StringData field to Data.
+// xref: https://github.com/kubernetes/kubernetes/issues/108008
+func normalizeSecret(object *corev1.Secret) {
+	if len(object.StringData) > 0 {
+		if object.Data == nil {
+			object.Data = make(map[string][]byte, len(object.StringData))
+		}
+		for k, v := range object.StringData {
+			object.Data[k] = []byte(v)
+		}
+		object.StringData = nil
+	}
+}