How can i set the default values of controller parameters?

I have a customers table on my database and a column named as "last_updated_by" . I want to add current users name as a plain text in this field.

I got devise installed on my app so it gives me the current_user parameter.I tried to add current_user.name to the customers_controllers permitted parameters but it did not worked.

1-
def customer_params
params.require(:customer).permit(:name, :last_updated_by=>current_user.name)
end

2-
def customer_params
  params[:last_updated_by] = current_user.name
  params.require(:customer).permit(:name, :last_updated_by)
end

3-
def customer_params
  last_updated_by = current_user.name
  params.require(:customer).permit(:name, :last_updated_by=>current_user.name)
end

How can i set some default values in controller.

If you need the last_updated_by param to go within the customer_params (customer hash key for ActionController::Parameters), then:

before_action :set_last_updated_by_param, only: :create

private

def set_last_updated_by_param
  params[:customer][:last_updated_by] = params.dig(:customer, :name)
end

The before_action callback adds the new key last_updated_by on the customer params only before the create action is executed.

Notice, no need to modify the customer_params to permit it.

As showed by @JohanWentholt, with_defaults seems to be the best way. Go for it.

Waiting the OP chooses the correct answer.