Ouija

Ouija is a RubyGem that makes configuration clean and simple. Separate concerns are in separate config files (yaml, currently). Configuration is kept DRY by allowing you to declare the bulk of the settings as common (hopefully) and then let's you override where necessary by environment and hostname. At runtime, Ouija collapses the configuration into one graph based on the current context -- hostname and environment (both of which can be overridden).

Installation

gem install ouija

Overriding

Ouija collapses config settings at runtime based on current hostname and environment. Tree structure is merged and values are overridden. Values that are arrays are also overridden, not merged. See usage example below.

Override precedence:

hosts entries override

environments entries which override

default entries

Usage example

Config file PROJECT_ROOT/config/ouija/foo.yml

default:
  output_dir: /usr/local/foo/results
  logging:
    log_dir: /var/log/foo
  output_queues:
    - 'NormalQueue'
environments:
  production:
    logging:
      level: ERROR
    output_queues:
      - 'NormalQueue'
      - 'SamplingQueue'
  staging:
    logging:
      level: INFO
  development:
    logging:
      level: DEBUG
    output_queues:
      - 'DevQueue'
hosts:
  My-MacBook-Pro.local:
    output_dir: ./results
    logging:
      log_dir: ./log

Driver script PROJECT_ROOT/script/foo

#!/usr/bin/env ruby
require 'rubygems'
require 'bundler/setup'
Bundler.require
require 'ouija'
Ouija.setup
planchette = Ouija.session('foo')
puts planchette.to_hash.inspect

Results on host with name My-MacBook-Pro.local

$ script/foo
{"output_dir"=>"./results", "logging"=>{"log_dir"=>"./log", "level"=>"DEBUG"}, "output_queues"=>["DevQueue"]}
$ OUIJA_ENV=staging script/foo
{"output_dir"=>"./results", "logging"=>{"log_dir"=>"./log", "level"=>"INFO"}, "output_queues"=>["NormalQueue"]}
$ OUIJA_ENV=production script/foo
{"output_dir"=>"./results", "logging"=>{"log_dir"=>"./log", "level"=>"ERROR"}, "output_queues"=>["NormalQueue", "SamplingQueue"]}

Legal stuff

Copyright (c) 2012, Rob Lewis (kohder)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.