databroker: add support for field masks on Put (#3210)

* databroker: add support for field masks on Put

* return errors

* clean up go.mod

pkg/protoutil/mask.go

@@ -0,0 +1,31 @@
+package protoutil
+
+import (
+	"github.com/mennanov/fmutils"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/anypb"
+	"google.golang.org/protobuf/types/known/fieldmaskpb"
+)
+
+// MergeAnyWithFieldMask merges the data in src with the data in dst,
+// but only the fields identified by the given mask.
+func MergeAnyWithFieldMask(dst, src *anypb.Any, mask *fieldmaskpb.FieldMask) (*anypb.Any, error) {
+	if mask == nil {
+		return src, nil
+	}
+
+	srcMsg, err := src.UnmarshalNew()
+	if err != nil {
+		return nil, err
+	}
+
+	dstMsg, err := dst.UnmarshalNew()
+	if err != nil {
+		return nil, err
+	}
+
+	fmutils.Filter(srcMsg, mask.GetPaths())
+	proto.Merge(dstMsg, srcMsg)
+
+	return anypb.New(dstMsg)
+}

pkg/protoutil/mask_test.go

@@ -0,0 +1,35 @@
+package protoutil
+
+import (
+	"testing"
+
+	envoy_type_v3 "github.com/envoyproxy/go-control-plane/envoy/type/v3"
+	"github.com/google/go-cmp/cmp"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/protobuf/testing/protocmp"
+	"google.golang.org/protobuf/types/known/fieldmaskpb"
+)
+
+func TestMergeWithFieldMask(t *testing.T) {
+	m1 := NewAny(&envoy_type_v3.SemanticVersion{
+		MajorNumber: 1,
+		MinorNumber: 1,
+		Patch:       1,
+	})
+	m2 := NewAny(&envoy_type_v3.SemanticVersion{
+		MajorNumber: 2,
+		MinorNumber: 2,
+		Patch:       2,
+	})
+	expect := NewAny(&envoy_type_v3.SemanticVersion{
+		MajorNumber: 2,
+		MinorNumber: 1,
+		Patch:       2,
+	})
+	actual, err := MergeAnyWithFieldMask(m1, m2, &fieldmaskpb.FieldMask{
+		Paths: []string{"major_number", "patch"},
+	})
+	require.NoError(t, err)
+	assert.Empty(t, cmp.Diff(expect, actual, protocmp.Transform()))
+}