using parameters with ruby require

Question

Is it possible to require files with arguments / parameters?

For example

resource.rb has

mode = ARGV.first

if mode == "prod"
  #use prod db
else
  #use test db
end

And main.rb requires it with params with something like

require_relative './resource.rb prod'

If this is not possible or bad practice please let me know. I guess I could use version control to switch between test and prod but it seems a little retarded.

(prod and test used only to differentiate. This is a pretty lightweight project and is not commercial if it makes any difference :) )

Using Ruby 1.9.3 on Windows XP thanks.

I am surprised that there were no answers on this already. Only stuff on using gems and using ruby with parameters but not both at the same time.

Answer 1

You cannot do that via a require, but you could set an environment variable:

In main.rb:

ENV["mode"] = ARGV.first
require_relative './resource'

In ./resource.rb:

mode = ENV.fetch("mode")

if mode == "prod"
  #use prod db
else
  #use test db
end

The advantage of using environment variables for configurations is that you can have the same logic across multiple files. That's the Heroku way of doing things.

See Heroku's 12 factor app.

Answer 2

No, you cannot pass parameters with require.

I'd suggest doing something like this:

def use_mode(mode)
  # your if statements
end

and then

require 'file'
use_mode :development

And wrap it up in a Class / Module for cleaner code :)