Validation

Fuda uses go-playground/validator tags when it loads configuration through fuda.New() or a convenience loader such as fuda.LoadBytes.

type Config struct {
    Host string `yaml:"host" validate:"required"`
    Port int    `yaml:"port" validate:"min=1,max=65535"`
}

Load a valid configuration

var cfg Config
err := fuda.LoadBytes([]byte("host: localhost\nport: 8080\n"), &cfg)
if err != nil {
    return err
}

Fuda loads the fields, applies tags, then validates the final struct. This order lets a default or environment variable satisfy a validation rule.

Handle a validation failure

var cfg Config
err := fuda.LoadBytes([]byte("host: \"\"\nport: 0\n"), &cfg)
if err != nil {
    return fmt.Errorf("invalid configuration: %w", err)
}

The required and min rules fail in this example. Return the error during startup so your application does not run with invalid configuration.

Next step

Choose the right data type for durations and byte sizes.