YAML-load_first

Add this line to your application's Gemfile:

# note that the case is important
gem 'YAML-load_first'

require like this (or use Bundle.require):

require 'yaml/load_first'

YAML-load_first works in the same way as YAML.load_file, but it takes an array of files, and will load the first one that exists. This can be used to load config files, looking at a number of locations until a matching one is found.

require 'yaml/load_first'

# the first matching file will be loaded as the config
CONFIG = YAML.load_first_file [
    "#{ENV['HOME']}/config/app.config", 
    "./config/prod.config", 
    "./config/dev.config"
]

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