Validatable interface

[kke]

There's UnmarshalJSON and UnmarshalYAML for the unmarshalers, then there's SetDefaults for the https://github.com/creasty/defaults but for the validator, you need to use the RegisterValidation thing.

Could the validator just call some kind of Validate() error function on all targets if they have it?

type Config struct {
  Attrs *Attributes
}

type Attributes struct {
  Setting bool
  Value valueString
}

type valueString string
func (v valueString) Validate() error {
  if strings.HasPrefix(v, "x") {
    return fmt.Errorf("can't start with x")
  }
  return nil
}

func (a Attributes) Validate() error {
  if a.Setting {
    return fmt.Errorf("this setting must be true")
  }
  return nil
}

[zemzale]

Hey @kke. This can be easily be achieved by this library using struct tags.

In your case this would

type Config struct {
        Attrs *Attributes
}

type Attributes struct {
        Setting bool        `validate:"required"`
        Value   valueString `validate:"startsnotwith=x"`
}

type valueString string

func TestValidatorMap(t *testing.T) {
        validate := validator.New()

        s := Attributes{
                Setting: true,
                Value:   "asdf",
        }
        if err := validate.Struct(s); err != nil {
                t.Fail()
        }
}

[kke]

@zemzale Thanks, but that only solves it for the example in the question, not the intention of it, which was custom validations just by implementing some function on the type instead of having to use RegisterValidation and adding a custom validation tag.

[zemzale]

I misunderstood the main question then. It's not possible to do with this library, and AFAIK is not in the scope of the library.

The exact behavior you are asking for is implemented by https://github.com/go-ozzo/ozzo-validation while this library has taken the approach of using struct tags for validation.

[mvrahden]

FYI: This was solved with #1363