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Anyway Config

Rails/Ruby plugin/application configuration tool which allows you to load parameters from different sources: YAML, Rails secrets, environment.

Allows you to easily follow the twelve-factor application principles and adds zero complexity to your development process.

Libraries using Anyway Config:

Installation

1) Adding to a gem:

# my-cool-gem.gemspec
Gem::Specification.new do |spec|
  ...
  spec.add_dependency "anyway_config", "~> 1.0"
  ...
end

2) Adding to your project:

# Gemfile
gem "anyway_config", "~> 1.0"

3) Install globally:

$ gem install anyway_config

Usage

Pre-defined configuration

Create configuration class:

require 'anyway'

module MyCoolGem
  class Config < Anyway::Config
    attr_config user: 'root', password: 'root', host: 'localhost'
  end
end

attr_config creates accessors and default values. If you don't need default values just write:

attr_config :user, :password, host: 'localhost'

Then create an instance of the config class and use it:

module MyCoolGem
  def self.config
    @config ||= Config.new
  end
end

MyCoolGem.config.user #=> 'root'

Customize name

By default, Anyway Config uses the namespace (the outer module name) as the config name, but you can set it manually:

module MyCoolGem
  class Config < Anyway::Config
    config_name :cool
    attr_config user: 'root', password: 'root', host: 'localhost', options: {}
  end
end

Provide explicit values

Sometimes it's useful to set some parameters explicitly during config initialization. You can do that using overrides option:

config = MyCoolGem::Config.new(
  overrides: {
    user: 'john',
    password: 'rubyisnotdead'
  }
)

# The value would not be overriden from other sources (such as YML file, env)
config.user == 'john'

Dynamic configuration

You can also create configuration objects without pre-defined schema (just like Rails.application.config_for but more powerful):

# load data from config/my_app.yml, secrets.my_app (if using Rails), ENV["MYAPP_*"]
config = Anyway::Config.for(:my_app)

Using with Rails

Your config will be filled up with values from the following sources (ordered by priority from low to high):

  • RAILS_ROOT/config/my_cool_gem.yml (for the current RAILS_ENV, supports ERB)

  • Rails.application.secrets.my_cool_gem

  • ENV['MYCOOLGEM_*'].

Using with Ruby

By default, Anyway Config is looking for a config YAML at ./config/<config-name>.yml. You can override this setting through special environment variable – 'MYGEM_CONF' – containing the path to the YAML file.

Environmental variables work the same way as with Rails.

Config clear and reload

There are #clear and #reload functions on your config (which do exactly what they state).

Note: #reload also accepts overrides key to provide explicit values (see above).

Rails.application.config_for vs Anyway::Config.for

Rails 4.2 introduced new feature: Rails.application.config_for. It looks very similar to Anyway::Config.for, but there are some differences:

Feature Rails Anyway Config
load data from config/app.yml yes yes
load data from secrets no yes
load data from environment no yes
return Hash with indifferent access no yes
support ERB within config/app.yml yes yes*
raise errors if file doesn't exist yes no

*make sure that ERB is loaded

But the main advantage of Anyway::Config is that it can be used without Rails!)

How to set env vars

Environmental variables for your config should start with your config name, uppercased and underscore-free.

For example, if your module is called "MyCoolGem" then the env var "MYCOOLGEM_PASSWORD" is used as config.password.

Environment variables are type-casted (case-insensitive).

Examples:

  • "True", "t" and "yes" to true;

  • "False", "f" and "no" to false;

  • "nil" and "null" to nil (do you really need it?);

  • "123" to 123 and "3.14" to 3.14.

Anyway Config supports nested (hashed) env variables. Just separate keys with double-underscore. For example, "MYCOOLGEM_OPTIONS__VERBOSE" is parsed as config.options.verbose.

Array values are also supported:

# Suppose ENV["MYCOOLGEM_IDS"] = '1,2,3'
config.ids #=> [1,2,3]

If you want to provide a text-like env variable which contains commas then wrap it into quotes:

MYCOOLGEM="Nif-Nif, Naf-Naf and Nouf-Nouf"

Contributing

  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request