validator_sample.go

package main

import (
	"fmt"

	"github.com/go-playground/validator"
)

type User struct {
	FirstName string `validate:"required"`       //必須
	LastName  string `validate:"required"`       //必須
	Age       uint8  `validate:"gte=0,lt=130"`   // 0 <= age < 130
	Email     string `validate:"required,email"` //必須, email フォーマット
}

func main() {
	user := &User{
		FirstName: "Kenzo",
		LastName:  "Tanaka",
		Age:       39,
		Email:     "kenzo.tanakagmail.com",
	}
	validate := validator.New()
	error := validate.Struct(user)
	fmt.Println(error) 	// Key: 'User.Email' Error:Field validation for 'Email' failed on the 'email' tag
}