Setting Environment Variables in Rails 3 (Devise + Omniauth)

I've been trying to figure out how Ryan Bates, in his Facebook Authentication screencast, is setting the following "FACEBOOK_APP_ID" and "FACEBOOK_SECRET" environment variables.

provider :facebook, ENV['FACEBOOK_APP_ID'], ENV['FACEBOOK_SECRET']

There are similar-ish questions around, but no answers that I've been able to get to work on Rails 3.2.1.

UPDATE:

As of May 2013, my preferred way to handle ENV variables is via the Figaro gem

Solution 1:

You could take a look at the comments:

You can either set environment variables directly on the shell where you are starting your server:

FACEBOOK_APP_ID=12345 FACEBOOK_SECRET=abcdef rails server

Or (rather hacky), you could set them in your config/environments/development.rb:

ENV['FACEBOOK_APP_ID'] = "12345";
ENV['FACEBOOK_SECRET'] = "abcdef";

An alternative way

However I would do neither. I would create a config file (say config/facebook.yml) which holds the corresponding values for every environment. And then load this as a constant in an initializer:

config/facebook.yml

development:
  app_id: 12345
  secret: abcdef

test:
  app_id: 12345
  secret: abcdef

production:
  app_id: 23456
  secret: bcdefg

config/initializers/facebook.rb

FACEBOOK_CONFIG = YAML.load_file("#{::Rails.root}/config/facebook.yml")[::Rails.env]

Then replace ENV['FACEBOOK_APP_ID'] in your code by FACEBOOK_CONFIG['app_id'] and ENV['FACEBOOK_SECRET'] by FACEBOOK_CONFIG['secret'].

Solution 2:

There are several options:

• Set the environment variables from the command line:

  export FACEBOOK_APP_ID=your_app_id
  export FACEBOOK_SECRET=your_secret
  

  You can put the above lines in your ~/.bashrc

• Set the environment variables when running rails s:

  FACEBOOK_APP_ID=your_app_id FACEBOOK_SECRET=your_secret rails s
  

• Create a .env file with:

  FACEBOOK_APP_ID=your_app_id
  FACEBOOK_SECRET=your_secret
  

  and use either Foreman (starting your app with foreman start) or the dotenv gem.

Solution 3:

Here's another idea. Define the keys and values in provider.yml file, as suggested above. Then put this in your environment.rb (before the call to Application.initialize!):

YAML.load_file("#{::Rails.root}/config/provider.yml")[::Rails.env].each {|k,v| ENV[k] = v }

Then these environment variables can be referenced in the omniauth initializer without any ordering dependency among intializers.