tx.go

func (db *DB) Transact(txFunc func(db *DB) error) (err error) {
	tx := db.Begin()
	if tx.Error == gorm.ErrCantStartTransaction {
		// transaction already in progress
		return txFunc(db)
	}
	defer func() {
		if r := recover(); r != nil {
			tx.Rollback()
			panic(r)
		}
		if err != nil {
			tx.Rollback()
			return
		}
		err = tx.Commit().Error
	}()
	return txFunc(&DB{tx})
}