resource: adding various helpers for working with resources

internal/resource/decode.go

@@ -0,0 +1,38 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package resource
+
+import (
+	"google.golang.org/protobuf/proto"
+
+	"github.com/hashicorp/consul/proto-public/pbresource"
+)
+
+// DecodedResource is a generic holder to contain an original Resource and its
+// decoded contents.
+type DecodedResource[V any, PV interface {
+	proto.Message
+	*V
+}] struct {
+	Resource *pbresource.Resource
+	Data     PV
+}
+
+// Decode will generically decode the provided resource into a 2-field
+// structure that holds onto the original Resource and the decoded contents.
+//
+// Returns an ErrDataParse on unmarshalling errors.
+func Decode[V any, PV interface {
+	proto.Message
+	*V
+}](res *pbresource.Resource) (*DecodedResource[V, PV], error) {
+	data := PV(new(V))
+	if err := res.Data.UnmarshalTo(data); err != nil {
+		return nil, NewErrDataParse(data, err)
+	}
+	return &DecodedResource[V, PV]{
+		Resource: res,
+		Data:     data,
+	}, nil
+}

internal/resource/decode_test.go

@@ -0,0 +1,66 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package resource_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"google.golang.org/protobuf/types/known/anypb"
+
+	"github.com/hashicorp/consul/internal/resource"
+	"github.com/hashicorp/consul/internal/resource/demo"
+	"github.com/hashicorp/consul/proto-public/pbresource"
+	pbdemo "github.com/hashicorp/consul/proto/private/pbdemo/v2"
+	"github.com/hashicorp/consul/proto/private/prototest"
+)
+
+func TestDecode(t *testing.T) {
+	t.Run("good", func(t *testing.T) {
+		fooData := &pbdemo.Artist{
+			Name: "caspar babypants",
+		}
+		any, err := anypb.New(fooData)
+		require.NoError(t, err)
+
+		foo := &pbresource.Resource{
+			Id: &pbresource.ID{
+				Type:    demo.TypeV2Artist,
+				Tenancy: demo.TenancyDefault,
+				Name:    "babypants",
+			},
+			Data: any,
+			Metadata: map[string]string{
+				"generated_at": time.Now().Format(time.RFC3339),
+			},
+		}
+
+		dec, err := resource.Decode[pbdemo.Artist, *pbdemo.Artist](foo)
+		require.NoError(t, err)
+
+		prototest.AssertDeepEqual(t, foo, dec.Resource)
+		prototest.AssertDeepEqual(t, fooData, dec.Data)
+	})
+
+	t.Run("bad", func(t *testing.T) {
+		foo := &pbresource.Resource{
+			Id: &pbresource.ID{
+				Type:    demo.TypeV2Artist,
+				Tenancy: demo.TenancyDefault,
+				Name:    "babypants",
+			},
+			Data: &anypb.Any{
+				TypeUrl: "garbage",
+				Value:   []byte("more garbage"),
+			},
+			Metadata: map[string]string{
+				"generated_at": time.Now().Format(time.RFC3339),
+			},
+		}
+
+		_, err := resource.Decode[pbdemo.Artist, *pbdemo.Artist](foo)
+		require.Error(t, err)
+	})
+}

internal/resource/equality.go

@@ -120,6 +120,18 @@ func EqualReference(a, b *pbresource.Reference) bool {
 		a.Section == b.Section
 }
 
+// ReferenceOrIDMatch compares two references or IDs to see if they both refer
+// to the same thing.
+func ReferenceOrIDMatch(ref1, ref2 ReferenceOrID) bool {
+	if ref1 == nil || ref2 == nil {
+		return false
+	}
+
+	return EqualType(ref1.GetType(), ref2.GetType()) &&
+		EqualTenancy(ref1.GetTenancy(), ref2.GetTenancy()) &&
+		ref1.GetName() == ref2.GetName()
+}
+
 // EqualStatusMap compares two status maps for equality without reflection.
 func EqualStatusMap(a, b map[string]*pbresource.Status) bool {
 	if len(a) != len(b) {