Example cleanup function for protobuf message

clear_proto.go

func clearProtoFields(msg proto.Message, sensitiveFieldAnnotation *protoimpl.ExtensionInfo) proto.Message {
	clonedMsg := proto.Clone(msg)
	reflectMsg := proto.MessageReflect(clonedMsg)
	var messagesToCheck []protoreflect.Message
	messagesToCheck = append(messagesToCheck, reflectMsg)

	for len(messagesToCheck) != 0 {
		lastIdx := len(messagesToCheck) - 1
		visitMessage := messagesToCheck[lastIdx]
		messagesToCheck = messagesToCheck[:lastIdx]

		visitMessage.Range(func(fd protoreflect.FieldDescriptor, val protoreflect.Value) bool {
			if opts := fd.Options().(*descriptorpb.FieldOptions); opts != nil {
				if proto.HasExtension(opts, sensitiveFieldAnnotation) {
					visitMessage.Clear(fd)
				}
				return true
			}
			switch {
			case fd.Kind() != protoreflect.MessageKind:
				return true
			case fd.IsList():
				listVal := val.List()
				for i := 0; i < listVal.Len(); i++ {
					elem := listVal.Get(i)
					messagesToCheck = append(messagesToCheck, elem.Message())
				}
			case fd.IsMap():
				mapVal := val.Map()
				mapVal.Range(func(k protoreflect.MapKey, v protoreflect.Value) bool {
					messagesToCheck = append(messagesToCheck, v.Message())
					return true
				})
			default:
				messagesToCheck = append(messagesToCheck, val.Message())
			}
			return true
		})
	}
	return clonedMsg
}