DynamoDB PartiQL transaction values using reflection

ddbvalue.go

func dynamoValue(i any) (string, []types.AttributeValue, error) {
	val := reflect.ValueOf(i)
	fields := reflect.VisibleFields(reflect.TypeOf(i))
	names := make([]string, 0)
	values := make([]types.AttributeValue, 0)
	for _, field := range fields {
		name := field.Tag.Get("dynamodbav")
		if name != "" && name != "-" {
			names = append(names, name)
			v := val.FieldByName(field.Name).Interface()
			attr, err := attributevalue.Marshal(v)
			if err != nil {
				return "", nil, err
			}
			values = append(values, attr)
		}
	}

	elems := make([]string, len(names))
	for i, name := range names {
		elems[i] = "\"" + name + "\":?"
	}

	str := fmt.Sprintf("{%s}", strings.Join(elems, ", "))

	return str, values, nil
}