App Configurable

Single source of truth for app configuration

App Configurable is a simple Ruby gem that provides a centralized and consistent way to manage application configurations. It allows you to define configurations in a single place and access them throughout your application, ensuring that your app's settings are always up-to-date and consistent across different environments.

Features

• Centralized configuration management
• Environment-specific settings
• Fail on demand or on app startup
• Support for namespaced and root-level configurations
• Easy integration with Rails applications

Installation

1. Add the gem to your Gemfile: ruby gem 'app_configurable'

2. Define your configurations in config/app_config.rb:

   class AppConfig
     include AppConfigurable
   
     entry :secret_key, default: 'your_secret_key'
     entry :base_url, default: 'http://my-site.local', production: 'http://  my-site.io', staging: 'http://staging.my-site.io'
   end
   

3. Load the configurations:

   Define an initializer config/initializers/_app_config.rb:

   AppConfigurable.load_configs(%w[./config/app_config.rb])
   

   OR

   AppConfigurable.load_configs(%w[./config/app_config.rb], rails_env: 'production') #  Set's environment to `production`.
   

   OR

   AppConfigurable.load_configs(%w[./config/app_config.rb], raise_on_missing: true) #  Fails on startup, reporting missing configs.
   

   Alternatively, you could define your configs under the autoloading path if failing on demand is acceptable.

4. Access your configurations:

   AppConfig.secret_key
   

Adding a config

There are two types of configurations:

• Namespaced: Used to store configurations grouped by attributes such as external service names (e.g., Hubspot).
• Root-level configs: Generic configurations for the app, such as rails_serve_static_files.

### Example ./config/app_config.rb:

  class AppConfig
    include AppConfigurable

    entry :secret_key_base, default: 'secret_key_base'
    entry :base_url, default: 'http://my-site.local', production: 'http://  my-site.io', staging: 'http://staging.my-site.io'
    entry :client_secret, default: 'client_secret_token'
  end

./config/app_config/hubspot.rb:

  class AppConfig::Hubspot
    include AppConfigurable

    entry :access_token, default: 'secret_access_token'
    entry :base_url, default: 'https://hubspot.com/1234', production: 'https:// hubspot.com/4321'
    entry :client_secret, default: 'client_secret_token'
  end

Declared configs can be accessed through: AppConfig.secret_key_base and AppConfig::Hubspot.base_url.

Attributes

Attributes are declared using the entry directive. Example: entry :rails_serve_static_files.

Options

• production/staging/development/test: Sets attributes per environment.
• default:
  • Sets the default attribute, used in production/staging/development environments as a fallback.
  • Accepts string/number/boolean as well as Proc/Lambda as a parameter.
  • In the test environment, always falls back to a dummy value some_super_dummy_#{namespaced_attribute_name} unless specified explicitly.

Priority

• production/staging/development:

  1. Find value in ENV.
  2. Find value in specific environment attribute passed to entry.
  3. Find value from default.
  4. Fail with AppConfig::Error::RequiredVarMissing.

• testing:

  1. Find value in ENV.
  2. Find value in test attribute of config entry.
  3. Return some_super_dummy_#{namespaced_attribute_name}, ignoring the specified default attribute.

Setting the Environment

By default your environment will is set from Rails.env.

Globally, when initialising configs:

AppConfigurable.load_configs(%w[./config/app_config.rb], rails_env: 'production').

Might be useful to disable error reporting for assets precompilation or any rake tasks which don't require secrets but loading full rails environment.

Per namespace:

Given namespace AppConfig::MyNiceConfigClass and .env.staging:

APPCONFIG_MYNICEMODULE_ENV=staging rspec

.env.#{RAILS_ENV} will be read per specific AppConfig::SomeNiceClass class.

TODO:

• Read Rails.application.credentials.
• Make dynamic switch possible, similar to what we have with ENV.