From cfabeb41d3800cf4b3431ddd5fdc3bae81158102 Mon Sep 17 00:00:00 2001
From: Alan Parra <alan.parra@goteleport.com>
Date: Mon, 11 Dec 2023 13:04:48 -0300
Subject: [PATCH] Adapt types.Resource to Resource153 (#35568)

---
 api/types/resource_153.go      | 64 ++++++++++++++++++++++++++++++++++
 api/types/resource_153_test.go | 36 +++++++++++++++++++
 2 files changed, 100 insertions(+)

diff --git a/api/types/resource_153.go b/api/types/resource_153.go
index 96af3799c5266..ddb4ff23c9aba 100644
--- a/api/types/resource_153.go
+++ b/api/types/resource_153.go
@@ -23,6 +23,12 @@ import (
 	headerv1 "github.com/gravitational/teleport/api/gen/proto/go/teleport/header/v1"
 )
 
+// ResourceMetadata is the smallest interface that defines a Teleport resource.
+type ResourceMetadata interface {
+	// GetMetadata returns the generic resource metadata.
+	GetMetadata() *headerv1.Metadata
+}
+
 // Resource153 is a resource that follows RFD 153.
 //
 // It exists as a weak guideline for fields that resource protos must provide
@@ -52,6 +58,64 @@ type Resource153 interface {
 	GetMetadata() *headerv1.Metadata
 }
 
+// LegacyToResource153 converts a legacy [Resource] into a [Resource153].
+//
+// Useful to handle old and new resources uniformly. If you can, consider
+// further "downgrading" the Resource153 interface into the smallest subset that
+// works for you (for example, [ResourceMetadata]).
+func LegacyToResource153(r Resource) Resource153 {
+	return &legacyToResource153Adapter{inner: r}
+}
+
+type legacyToResource153Adapter struct {
+	inner Resource
+}
+
+// Unwrap is an escape hatch for Resource instances that are piped down into the
+// codebase as a legacy Resource.
+//
+// Ideally you shouldn't depend on this.
+func (r *legacyToResource153Adapter) Unwrap() Resource {
+	return r.inner
+}
+
+// MarshalJSON adds support for marshaling the wrapped resource (instead of
+// marshaling the adapter itself).
+func (r *legacyToResource153Adapter) MarshalJSON() ([]byte, error) {
+	return json.Marshal(r.inner)
+}
+
+func (r *legacyToResource153Adapter) GetKind() string {
+	return r.inner.GetKind()
+}
+
+func (r *legacyToResource153Adapter) GetMetadata() *headerv1.Metadata {
+	md := r.inner.GetMetadata()
+
+	var expires *timestamppb.Timestamp
+	if md.Expires != nil {
+		expires = timestamppb.New(*md.Expires)
+	}
+
+	return &headerv1.Metadata{
+		Name:        md.Name,
+		Namespace:   md.Namespace,
+		Description: md.Description,
+		Labels:      md.Labels,
+		Expires:     expires,
+		Id:          md.ID,
+		Revision:    md.Revision,
+	}
+}
+
+func (r *legacyToResource153Adapter) GetSubKind() string {
+	return r.inner.GetSubKind()
+}
+
+func (r *legacyToResource153Adapter) GetVersion() string {
+	return r.inner.GetVersion()
+}
+
 // Resource153ToLegacy transforms an RFD 153 style resource into a legacy
 // [Resource] type.
 //
diff --git a/api/types/resource_153_test.go b/api/types/resource_153_test.go
index 9b5fd370a6c8c..7dc0ed5221ac6 100644
--- a/api/types/resource_153_test.go
+++ b/api/types/resource_153_test.go
@@ -27,6 +27,42 @@ import (
 	"github.com/gravitational/teleport/api/types"
 )
 
+func TestLegacyToResource153(t *testing.T) {
+	// user is an example of a legacy resource.
+	// Any other resource type would to.
+	user := &types.UserV2{
+		Kind: "user",
+		Metadata: types.Metadata{
+			Name: "llama",
+		},
+		Spec: types.UserSpecV2{
+			Roles: []string{"human", "camelidae"},
+		},
+	}
+
+	resource := types.LegacyToResource153(user)
+
+	// Unwrap gives the underlying resource back.
+	t.Run("unwrap", func(t *testing.T) {
+		unwrapped := resource.(interface{ Unwrap() types.Resource }).Unwrap()
+		if diff := cmp.Diff(user, unwrapped, protocmp.Transform()); diff != "" {
+			t.Errorf("Unwrap mismatch (-want +got)\n%s", diff)
+		}
+	})
+
+	// Marshaling as JSON marshals the underlying resource.
+	t.Run("marshal", func(t *testing.T) {
+		jsonBytes, err := json.Marshal(resource)
+		require.NoError(t, err, "Marshal")
+
+		user2 := &types.UserV2{}
+		require.NoError(t, json.Unmarshal(jsonBytes, user2), "Unmarshal")
+		if diff := cmp.Diff(user, user2, protocmp.Transform()); diff != "" {
+			t.Errorf("Marshal/Unmarshal mismatch (-want +got)\n%s", diff)
+		}
+	})
+}
+
 func TestResource153ToLegacy(t *testing.T) {
 	// bot is an example of an RFD 153 "compliant" resource.
 	// Any other resource type would do.