How to define custom configuration variables in rails

Question

I was wondering how to add custom configuration variables to a rails application and how to access them in the controller, for e.g I want to be able to define an upload_directory in the configuration files say development.rb and be able to access it in one of my controllers.

Secondly I was planning to have S3 support for uploads in my application, if I wanted to add a yaml file with the s3 access, secret key, how do I initialize it in my Rails App and how do I access the values that I have defined in that config file.

Answer 1

Update 1

Very recommended: I'm going with Rails Config gem nowadays for the fine grained control it provides.

Update2

If you want a quick solution, then check Jack Pratt's answer below.

Although my original answer below still works, this answer is now outdated. I recommend looking at updates 1 and 2.

Original Answer:

For a quick solution, watching the "YAML Configuration File" screen cast by Ryan Bates should be very helpful.

In summary:

# config/initializers/load_config.rb
APP_CONFIG = YAML.load_file("#{Rails.root}/config/config.yml")[Rails.env]

# application.rb
if APP_CONFIG['perform_authentication']
  # Do stuff
end

Answer 2

In Rails 3, Application specific custom configuration data can be placed in the application configuration object. The configuration can be assigned in the initialization files or the environment files -- say for a given application MyApp:

MyApp::Application.config.custom_config_variable = :my_config_setting

or

Rails.configuration.custom_config_variable = :my_config_setting

To read the setting, simply call the configuration variable without setting it:

Rails.configuration.custom_config_variable
=> :my_config_setting

UPDATE Rails 4

In Rails 4 there a new way for this => http://guides.rubyonrails.org/configuring.html#custom-configuration

Answer 3

In Rails 3.0.5, the following approach worked for me:

In config/environments/development.rb, write

config.custom_config_key = :config_value

The value custom_config_key can then be referenced from other files using

Rails.application.config.custom_config_key

Answer 4

This works in rails 3.1:

in config/environment.rb (or in config/environments/.. to target a specific environment) :

YourApp::Application.config.yourKey = 'foo'

This will be accessible in controller or views like this:

YourApp::Application.config.yourKey

(YourApp should be replaced by your application name.)

Note: It's Ruby code, so if you have a lot of config keys, you can do this :

in config/environment.rb :

YourApp::Application.configure do
  config.something = foo
  config.....
  config....
  .
  config....
end

Answer 5

In Rails 4

Assuming you put your custom variables into a yaml file:

# config/acme.yml
development:
  :api_user: 'joe'
  :api_pass: 's4cret'
  :timeout: 20

Create an initializer to load them:

# config/initializers/acme.rb
acme_config = Rails.application.config_for :acme

Rails.application.configure do
  config.acme = ActiveSupport::OrderedOptions.new
  config.acme.api_user = acme_config[:api_user]
  config.acme.api_pass = acme_config[:api_pass]
  config.acme.timeout  = acme_config[:timeout]
end

Now anywhere in your app you can access these values like so:

Rails.configuration.acme.api_user

It is convenient that Rails.application.config_for :acme will load your acme.yml and use the correct environment.

Answer 6

Since Rails 4.2, without additional gems, you can load config/hi.yml simply by using Rails.application.config_for :hi.

For example:

1. touch config/passwords.yml

       #config/passwords.yml
       development:
         username: 'a'
         password: 'b'
       production:
         username: 'aa'
         password: 'bb'
   

2. touch config/initializers/constants.rb

   #config/initializers/constants.rb
   AUTHENTICATION = Rails.application.config_for :passwords
   

3. and now you can use AUTHENTICATION constant everywhere in your application:

   #rails c production
   :001> AUTHENTICATION['username'] => 'aa'
   

4. then add passwords.yml to .gitignore: echo /config/passwords.yml >> .gitignore, create an example file for your comfort cp /config/passwords.yml /config/passwords.example.yml and then just edit your example file in your production console with actual production values.

Answer 7

I just wanted to update this for the latest cool stuff in Rails 4.2, you can now do this inside any of your config/**/*.rb files:

config.x.whatever.you.want = 42

...and this will be available in your app as:

Rails.configuration.x.whatever.you.want

See more here: http://guides.rubyonrails.org/configuring.html#custom-configuration

Answer 8

Check out this neat gem doing exactly that: https://github.com/mislav/choices

This way your sensitive data won't be exposed in open source projects

Answer 9

I created a simple plugin for YAML settings: Yettings

It works in a similar fashion to the code in khelll's answer, but you only need to add this YAML configuration file:

app/config/yetting.yml

The plugin dynamically creates a class that allows you to access the YML settings as class methods in your app like so:

Yetting.your_setting

Also, if you want to use multiple settings files with unique names, you can place them in a subdirectory inside app/config like this:

app/config/yettings/first.yml
app/config/yettings/second.yml

Then you can access the values like this:

FirstYetting.your_setting
SecondYetting.your_setting

It also provides you with default settings that can be overridden per environment. You can also use erb inside the yml file.

Answer 10

I really like the settingslogic gem. Very easy to set up and use.

https://github.com/binarylogic/settingslogic

Answer 11

If you use Heroku or otherwise have need to keep your application settings as environment variables, the figaro gem is very helpful.

Answer 12

I like to use rails-settings for global configuration values that need to be changeable via web interface.

Answer 13

Rails 6

Many outdated answers, so adding one that is specific to Rails 6.

Application specific configuration goes in initializer files. Details are here: edge guides

Example:

config/initializers/foo.rb

module MyApp
  class Application < Rails::Application
    config.test_val = 'foo'
  end
end

Alternatively:

Rails.application.config.test_val = 'foo'

This can now be accessed as:

Rails.configuration.test_val

Many more possibilities. edge guides #custom-configuration

ex, you can also set up nested namespace configurations:

config.x.payment_processing.schedule = :daily
config.x.payment_processing.retries  = 3
config.super_debugger = true

or use config_for to load entire custom config files:

config/payment.yml

production:
  environment: production
  merchant_id: production_merchant_id
  public_key:  production_public_key
  private_key: production_private_key

development:
  environment: sandbox
  merchant_id: development_merchant_id
  public_key:  development_public_key
  private_key: development_private_key

Then load it with:

config/initializers/load_payment.rb

module MyApp
  class Application < Rails::Application
    config.payment = config_for(:payment)
  end
end

Answer 14

Something we've starting doing at work is the ActiveSupport Ordered Hash

Which allows you to define your configuration cleanly inside the environment files e.g.

config.service = ActiveSupport::OrderedOptions.new
config.service.api_key = ENV['SERVICE_API_KEY']
config.service.shared_secret = ENV['SERVICE_SHARED_SECRET']

Answer 15

I would suggest good approach how to deal with configuration in your application at all. There are three basic rules:

• change your configuration not a code;
• use configurations over conditions;
• write code that means something.

To have more detailed overview follow this link: Rails configuration in the proper way