Add AuthenticatableType duck type (#3056)

* Add AuthenticatableType

* Add Resolver for AuthenticatableType

* Run gofmt and goimports

* Fix linter issues

apis/duck/v1/auth_types.go

@@ -16,6 +16,21 @@ limitations under the License.
 
 package v1
 
+import (
+	"context"
+	"fmt"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"knative.dev/pkg/apis"
+	"knative.dev/pkg/apis/duck/ducktypes"
+	"knative.dev/pkg/kmeta"
+	"knative.dev/pkg/ptr"
+)
+
+// +genduck
+
 // AuthStatus is meant to provide the generated service account name
 // in the resource status.
 type AuthStatus struct {
@@ -28,3 +43,81 @@ type AuthStatus struct {
 	// when the component uses multiple identities (e.g. in case of a Parallel).
 	ServiceAccountNames []string `json:"serviceAccountNames,omitempty"`
 }
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+
+// AuthenticatableType is a skeleton type wrapping AuthStatus in the manner we expect
+// resource writers defining compatible resources to embed it.  We will
+// typically use this type to deserialize AuthenticatableType ObjectReferences and
+// access the AuthenticatableType data.  This is not a real resource.
+type AuthenticatableType struct {
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata,omitempty"`
+
+	Status AuthenticatableStatus `json:"status"`
+}
+
+type AuthenticatableStatus struct {
+	// Auth contains the service account name for the subscription
+	// +optional
+	Auth *AuthStatus `json:"auth,omitempty"`
+}
+
+var (
+	// AuthStatus is a Convertible type.
+	_ apis.Convertible = (*AuthStatus)(nil)
+
+	// Verify AuthenticatableType resources meet duck contracts.
+	_ apis.Listable         = (*AuthenticatableType)(nil)
+	_ ducktypes.Populatable = (*AuthenticatableType)(nil)
+	_ kmeta.OwnerRefable    = (*AuthenticatableType)(nil)
+)
+
+// GetFullType implements duck.Implementable
+func (*AuthStatus) GetFullType() ducktypes.Populatable {
+	return &AuthenticatableType{}
+}
+
+// ConvertTo implements apis.Convertible
+func (a *AuthStatus) ConvertTo(_ context.Context, to apis.Convertible) error {
+	return fmt.Errorf("v1 is the highest known version, got: %T", to)
+}
+
+// ConvertFrom implements apis.Convertible
+func (a *AuthStatus) ConvertFrom(_ context.Context, from apis.Convertible) error {
+	return fmt.Errorf("v1 is the highest known version, got: %T", from)
+}
+
+// Populate implements duck.Populatable
+func (t *AuthenticatableType) Populate() {
+	t.Status = AuthenticatableStatus{
+		Auth: &AuthStatus{
+			// Populate ALL fields
+			ServiceAccountName: ptr.String("foo"),
+			ServiceAccountNames: []string{
+				"bar",
+				"baz",
+			},
+		},
+	}
+}
+
+// GetGroupVersionKind implements kmeta.OwnerRefable
+func (t *AuthenticatableType) GetGroupVersionKind() schema.GroupVersionKind {
+	return t.GroupVersionKind()
+}
+
+// GetListType implements apis.Listable
+func (*AuthenticatableType) GetListType() runtime.Object {
+	return &AuthenticatableTypeList{}
+}
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+
+// AuthenticatableTypeList is a list of AuthenticatableType resources
+type AuthenticatableTypeList struct {
+	metav1.TypeMeta `json:",inline"`
+	metav1.ListMeta `json:"metadata"`
+
+	Items []AuthenticatableType `json:"items"`
+}