func execTags(in interface{}, fs *pflag.FlagSet) error {
if reflect.TypeOf(in).Kind() != reflect.Ptr {
return errors.New("Calling parser with non-pointer")
}
if reflect.ValueOf(in).Elem().Kind() != reflect.Struct {
return errors.New("Calling parser with pointer to non-struct")
}
st := reflect.ValueOf(in).Elem()
for i := 0; i < st.NumField(); i++ {
valField := st.Field(i)
typeField := st.Type().Field(i)
if typeField.Tag.Get("default") == "" && typeField.Tag.Get("env") == "" && typeField.Tag.Get("flag") == "" && typeField.Type.Kind() != reflect.Struct {
// None of our supported tags is present and it's not a sub-struct
continue
}
value := varDefault(typeField.Tag.Get("vardefault"), typeField.Tag.Get("default"))
value = envDefault(typeField.Tag.Get("env"), value)
parts := strings.Split(typeField.Tag.Get("flag"), ",")
switch typeField.Type.Kind() {
case reflect.String:
if typeField.Tag.Get("flag") != "" {
if len(parts) == 1 {
fs.StringVar(valField.Addr().Interface().(*string), parts[0], value, typeField.Tag.Get("description"))
} else {
fs.StringVarP(valField.Addr().Interface().(*string), parts[0], parts[1], value, typeField.Tag.Get("description"))
}
} else {
valField.SetString(value)
}
case reflect.Bool:
v := value == "true"
if typeField.Tag.Get("flag") != "" {
if len(parts) == 1 {
fs.BoolVar(valField.Addr().Interface().(*bool), parts[0], v, typeField.Tag.Get("description"))
} else {
fs.BoolVarP(valField.Addr().Interface().(*bool), parts[0], parts[1], v, typeField.Tag.Get("description"))
}
} else {
valField.SetBool(v)
}
case reflect.Int, reflect.Int8, reflect.Int32, reflect.Int64:
vt, err := strconv.ParseInt(value, 10, 64)
if err != nil {
if value == "" {
vt = 0
} else {
return err
}
}
if typeField.Tag.Get("flag") != "" {
registerFlagInt(typeField.Type.Kind(), fs, valField.Addr().Interface(), parts, vt, typeField.Tag.Get("description"))
} else {
valField.SetInt(vt)
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
vt, err := strconv.ParseUint(value, 10, 64)
if err != nil {
if value == "" {
vt = 0
} else {
return err
}
}
if typeField.Tag.Get("flag") != "" {
registerFlagUint(typeField.Type.Kind(), fs, valField.Addr().Interface(), parts, vt, typeField.Tag.Get("description"))
} else {
valField.SetUint(vt)
}
case reflect.Float32, reflect.Float64:
vt, err := strconv.ParseFloat(value, 64)
if err != nil {
if value == "" {
vt = 0.0
} else {
return err
}
}
if typeField.Tag.Get("flag") != "" {
registerFlagFloat(typeField.Type.Kind(), fs, valField.Addr().Interface(), parts, vt, typeField.Tag.Get("description"))
} else {
valField.SetFloat(vt)
}
case reflect.Struct:
if err := execTags(valField.Addr().Interface(), fs); err != nil {
return err
}
case reflect.Slice:
switch typeField.Type.Elem().Kind() {
case reflect.Int:
def := []int{}
for _, v := range strings.Split(value, ",") {
it, err := strconv.ParseInt(strings.TrimSpace(v), 10, 64)
if err != nil {
return err
}
def = append(def, int(it))
}
if len(parts) == 1 {
fs.IntSliceVar(valField.Addr().Interface().(*[]int), parts[0], def, typeField.Tag.Get("description"))
} else {
fs.IntSliceVarP(valField.Addr().Interface().(*[]int), parts[0], parts[1], def, typeField.Tag.Get("description"))
}
case reflect.String:
del := typeField.Tag.Get("delimiter")
if len(del) == 0 {
del = ","
}
def := strings.Split(value, del)
if len(parts) == 1 {
fs.StringSliceVar(valField.Addr().Interface().(*[]string), parts[0], def, typeField.Tag.Get("description"))
} else {
fs.StringSliceVarP(valField.Addr().Interface().(*[]string), parts[0], parts[1], def, typeField.Tag.Get("description"))
}
}
}
}
return nil
}