util: Add support for time.Time in goproto struct

go.mod

@@ -179,6 +179,7 @@ require (
 	github.com/coreos/go-systemd/v22 v22.5.0 // indirect
 	github.com/couchbase/vellum v1.0.2 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.5 // indirect
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	github.com/dlclark/regexp2 v1.11.4 // indirect
 	github.com/docker/go-units v0.5.0 // indirect

pkg/goproto/struct.go

@@ -17,6 +17,7 @@ package goproto
 import (
 	"fmt"
 	"reflect"
+	"time"
 
 	"go.thethings.network/lorawan-stack/v3/pkg/errors"
 	"google.golang.org/protobuf/types/known/structpb"
@@ -203,6 +204,12 @@ func valueFromReflect(rv reflect.Value, opts ...Option) (*structpb.Value, error)
 		return &structpb.Value{Kind: &structpb.Value_StructValue{StructValue: pv}}, nil
 
 	case reflect.Struct:
+		if rv.Type() == reflect.TypeOf(time.Time{}) {
+			return &structpb.Value{Kind: &structpb.Value_StringValue{
+				StringValue: rv.Interface().(time.Time).Format(time.RFC3339Nano),
+			}}, nil
+		}
+
 		state, err := createSerializationState(opts...)
 		if err != nil {
 			return nil, err

pkg/goproto/struct_test.go

@@ -18,6 +18,7 @@ import (
 	"bytes"
 	"reflect"
 	"testing"
+	"time"
 
 	"github.com/smarty/assertions"
 	"github.com/spf13/cast"
@@ -55,6 +56,7 @@ func TestStructProto(t *testing.T) {
 		"map":            map[string]string{"foo": "bar"},
 		"eui":            types.EUI64{1, 2, 3, 4, 5, 6, 7, 8},
 		"jsonMarshaler":  &jsonMarshaler{Text: "testtext"},
+		"time":           time.Time{},
 	}
 	s, err := goproto.Struct(m)
 	a.So(err, should.BeNil)
@@ -106,6 +108,14 @@ func TestStructProto(t *testing.T) {
 			}
 
 		case reflect.Struct, reflect.Map:
+			if rv.Type() == reflect.TypeOf(time.Time{}) {
+				var vt string
+				a.So(s.Fields[k].Kind, should.HaveSameTypeAs, &structpb.Value_StringValue{})
+				a.So(sm[k], should.HaveSameTypeAs, vt)
+				a.So(sm[k], should.Equal, rv.Interface().(time.Time).Format(time.RFC3339Nano))
+				continue
+			}
+
 			var vt map[string]any
 			a.So(s.Fields[k].Kind, should.HaveSameTypeAs, &structpb.Value_StructValue{})
 			a.So(sm[k], should.HaveSameTypeAs, vt)