Setler

Setler is a Gem that lets one easily implement the “Feature Flags” pattern, or add settings to individual models. This is a cleanroom implementation of what the ‘rails-settings’ gem does. It’s been forked all over the place, and my favorite version of it doesn’t have any tests and doesn’t work with settings associated with models.

While Setler enables you to create both app-level and model-level settings, they are two separate things and don’t mix. For example, if you create defaults for the app, they won’t appear as defaults for individual models.

Setup

Install the gem by adding this to your Gemfile:

gem "setler"

Generate the model:

rails g setler <model_name>

Run the migration:

rake db:migrate

If you are using the ‘protected_attributes` gem you must add `attr_protected` to the top of you setler model.

Usage

Create/Update settings:

# Method calls and []= are synonymous
Featureflags.bacon_dispenser_enabled = true
Settings[:allowed_meats] = ['bacon', 'crunchy bacon']

Read settings:

Featureflags.bacon_dispenser_enabled # true
Settings[:allowed_meats].include?('bacon')  # true

Destroy them:

Featureflags.destroy :bacon_dispenser_enabled
Settings.destroy :allowed_meats

List all settings:

Featureflags.all_settings
Settings.all_settings

Set defaults in an initializer with something like:

Featureflags.defaults[:bacon_dispenser_enabled] = false
Settings.defaults[:allowed_meats] = ['itsnotbacon']

To revert to the default after changing a setting, destroy it. Note: Updating the setting to nil or false no longer makes it the default setting (> 0.0.6), but changes the setting to nil or false.

Add them to any ActiveRecord object:

class User < ActiveRecord::Base
  has_setler  :settings
end

Then you get:

user = User.first
user.settings.favorite_meat = :bacon
user.settings.favorite_meat  # :bacon
user.settings.all # { "favorite_meat" => :bacon }

TODO: And look em up:

User.with_settings_for('favorite_meat') # => scope of users with the favorite_meat setting

Gem Development

Getting started is pretty straightforward:

1. Check out the code:  `git clone git://github.com/ckdake/setler.git`
2. Bundle install:  `bundle install`
3. Run:  `appraisal install`  to generate the appraisal's gemfiles.
4. Run the tests for all supported releases in Appraisals file and make sure they all pass and code coverage is still the same:  `appraisal rake test`

If you’d like to contribute code, make your changes and submit a pull request that includes appropriate tests

For building the gem: ‘rake build` and to release a gem to github and Rubygems: `rake release`