Set ENV variables for Ruby on Rails

Question

I've followed the steps from this video from railscasts for setting ENV variables.

This is my configuration:

config/database.yml

default: &default
  adapter: mysql2
  encoding: utf8
  pool: 5
  username: <%= ENV['DATABASE_USERNAME'] %>
  password: <%= ENV['DATABASE_PASSWORD'] %>
  socket: /var/run/mysqld/mysqld.sock

development:
  <<: *default
database: <%= ENV['DATABASE_NAME'] %>
test:
  <<: *default
database: <%= ENV['DATABASE_NAME'] %>
production:
  <<: *default
  database: <%= ENV['DATABASE_NAME'] %>
  username: <%= ENV['DATABASE_USERNAME'] %>
password: <%= ENV['DATABASE_PASSWORD'] %>

config/application.rb

config = YAML.load(File.read(File.expand_path('../application.yml', __FILE__)))
config.merge! config.fetch(Rails.env, {})
config.each do |key, value|
    ENV[key] = value.to_s unless value.kind_of? Hash
end

config/application.yml

development:

  DATABASE_USERNAME: "username goes here"
  DATABASE_PASSWORD: "password goes here"
  DATABASE_NAME: "database name goes here"

  SECRET_KEY_BASE: "secret key goes here"

test:

  DATABASE_USERNAME: "username goes here"
  DATABASE_PASSWORD: "password goes here"
  DATABASE_NAME: "database name goes here"

  SECRET_KEY_BASE: "secret key goes here"

production:

  DATABASE_USERNAME: "username goes here"
  DATABASE_PASSWORD: "password goes here"
  DATABASE_NAME: "database name goes here"

  SECRET_KEY_BASE: "secret key goes here"

Does this configuration follow best practices, or need some changes?

Answer 1

for what you use config/application.yml instead use config/secrets.yml. It is already implemented in Rails. Than you can fetch your key by:

Rails.application.secrets

even more, add to config/application.rb variable SECRETS = Rails.application.secrets and now you can use it:

SECRETS[:my_secret_key]

read more IN RAILS DOCS

Answer 2

An Alternative is ..

Add gem 'config' to your Gemfile and run bundle install to install it. Then run

rails g config:install

which will generate customizable config file config/initializers/config.rb and set of default settings files:

config/settings.yml
config/settings/development.yml
config/settings/production.yml
config/settings/test.yml

You can now edit them to adjust to your needs. a

see the usage in https://github.com/railsconfig/config compatible Rails >= 3.1, 4 and 5