the business logic in transaction

registrationTransaction.go

// The use case of ModifyAndUnregister without transaction
func (ruc *RegistrationUseCase) ModifyAndUnregister(user *model.User) error {
	return modifyAndUnregister(ruc, user)
}

// The use case of ModifyAndUnregister with transaction
func (ruc *RegistrationUseCase) ModifyAndUnregisterWithTx(user *model.User) error {
	tdi, err := ruc.TxDataInterface.TxBegin()
	if err != nil {
		return errors.Wrap(err, "")
	}
	ruc.EnableTx()
	return tdi.TxEnd(func() error {
		// wrap the business function inside the TxEnd function
		return modifyAndUnregister(ruc, user)
	})
}

// The business function will be wrapped inside a transaction and inside a non-transaction function
// It needs to be written in a way that every error will be returned so it can be catched by TxEnd() function,
// which will handle commit and rollback
func modifyAndUnregister(ruc *RegistrationUseCase, user *model.User) error {
	udi := ruc.UserDataInterface
	err := modifyUser(udi, user)
	if err != nil {
		return errors.Wrap(err, "")
	}
	err = unregisterUser(udi, user.Name)
	if err != nil {
		return errors.Wrap(err, "")
	}
	return nil
}

func (ruc *RegistrationUseCase) EnableTx() {
	// Only UserDataInterface need transaction support here. If there are other data services need it,
	// then they also need to enable transaction here
	ruc.UserDataInterface.EnableTx(ruc.TxDataInterface)
}