Gaston is a store configuration that can be used in any Ruby project, it was released a bit more than year ago. We use it on most of our Ruby projects but Gaston didn't have the honours of a blog post yet.

Installation

Ruby 1.9.2 is required.

Install it with rubygems:

gem install gaston

With bundler, add it to your Gemfile:

gem "gaston"

Environment

Let's take a look at this yaml file containing some configuration values.

:gaston:
  :api:
    :state: "awesome"
:development:
  :api:
    :token: "api_token"
:test:
  :api:
    :token: <%= ENV["API_TOKEN"] %>

Gaston allows to specify different values depending on the environment. The gaston environment represents the default values that all environments inherit, unless a given value is overwritten in a specific environment.

In development environment, calling Gaston.api will yield the following hash:

{
  "state" => "awesome",
  "token" => "api_token"
}

In test environment (with the Environment variable set to "269596961710045034"), calling Gaston.api will yield the following hash:

{
  "state"=>"awesome",
  "token" => "269596961710045034"
}

This example also shows that gaston accepts Ruby code as a value through ERB templating.

Gaston also accepts json files:

{
  "gaston":{
    "hostname":"dev.af83.com"
  }
}

The same rules apply here.

A small setup is required to use Gaston. You can define an environment with the env method and specify config files with the files method. Default env is :development.

require 'gaston'

Gaston.configure do |gaston|
  gaston.env = ENV['ENV']
  gaston.files = Dir['*.yml', '*.json']
end

Gaston.api
# => {:state=>"awesome", :token=>"api_token"}
Gaston.hostname
# "dev.af83.com"

One last thing

At its core, Gaston inherits from the Ruby core class Hash. A Gaston store give access to all the methods defined on the Hash class. So you can use the classic keys, fetch methods. In order to do that, Gaston does not allow key names that are also a method defined on Hash. In this case, Gaston does not add this part of the configuration and logs a warning.