NxtConfig

This is a very simple tool to load YAML files into strict configuration structs, accessible through global constants. This is inspired by the famous config gem. The core features are:

• Load the content of a YAML file as a configuration object
• Strict attribute accessors
• Infinite amount of YAML files/configuration objects loadable (not just one)
• Configuration objects can be registered in a given namespace (especially useful when in use in ruby gems loaded by other applications) by calling NxtConfig::load in the namespace where the constant lives that its config struct is assigned to.

Add this line to your application's Gemfile:

gem 'nxt_config'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install nxt_config

You can create a configuration object using NxtConfig.load from YAML files or directly from a hash. If you are in a rails application, you can do this in an initializer (e.g. config/initializers/nxt_config.rb).

module MyRailsApp
  ExternalApiConfig = NxtConfig.load Rails.root.join('config', 'external_api.yml.erb')
end

Of course you can also load configuration structs everywhere else in the application. Depending on where you assign it to a constant, you can have many configuration structs available via constants namespaced all over your application, scoped to the context where you need them.

# Use struct like method chaining to access nested data
MyRailsApp::ExternalApiConfig.http.headers.user_agent
# => "MyRailsApp 1.0.0"

# The struct methods are strict, so they raise an error if the attribute does not exist
MyRailsApp::ExternalApiConfig.non_existent_key
# => raises NoMethodError

# You can also use hash like #fetch calls with symbols (multiple ones, like with Hash#dig)
MyRailsApp::ExternalApiConfig.fetch(:http, :headers, :user_agent)
# => "MyRailsApp 1.0.0"

# You can also use hash like #fetch calls with strings (multiple ones, like with Hash#dig)
MyRailsApp::ExternalApiConfig.fetch("http", "headers", "user_agent")
# => "MyRailsApp 1.0.0"

MyRailsApp::ExternalApiConfig.fetch(:http, :oh_no, :user_agent, &Proc.new { 'Hy!' })
# => "Hy!"

# You can also pass a block to #fetch in case a key does not exist

# If you don't walk through the struct until its leaves, you will get a sub struct
MyRailsApp::ExternalApiConfig.http
# => #<NxtConfig::Struct:0x00007fe657467680 @hash={"headers"=>#<NxtConfig::Struct:0x00007fe657467518 @hash={"user_agent"=>"my cool app", "api_key"=>"secret123"}>}>

After checking out the repo, run bin/setup to install dependencies. Then, run bin/rspec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Run bin/guard for guard to start watching for file changes and running the corresponding specs accordingly.

Bug reports and pull requests are welcome on GitHub at https://github.com/nxt-insurance/nxt_config.

The gem is available as open source under the terms of the MIT License.