:flags: Flagship :ship:

Ship/unship features using flags defined with declarative DSL.

Installation

Add this line to your application's Gemfile:

gem 'flagship'

And then execute:

$ bundle

Or install it yourself as:

$ gem install flagship

Usage

Define and use a flagset

Flagship.define :app do
  enable  :stable_feature
  enable  :experimental_feature, if: ->(context) { context.current_user.staff? }
  disable :deprecate_feature
end

Flagship.set_flagset(:app)

Branch with a flag

if Flagship.enabled?(:some_feature)
  # Implement the feature here
end

Set context variables

Both of below can be called as context.foo from :if block.

# Set a value
Flagship.set_context :foo, 'FOO'

# Set a lambda
Flagship.set_context :foo, ->(context) { 'FOO' }

Or you can set a method too.

Flagship.set_method :current_user, method(:current_user)

Extend flagset

Flagship.define :common do
  enable :stable_feature
end

Flagship.define :development, extend: :common do
  enable :experimental_feature
end

Flagship.define :production, extend: :common do
  disable :experimental_feature
end

if Rails.env.production?
  Flagset.set_flagset(:production)
else
  Flagset.set_flagset(:development)
end

Override flag with ENV

You can override flags with ENV named FLAG_***.

Assuming that there is a flag :foo, you can override it with ENV FLAGSHIP_FOO=1.

Development

After checking out the repo, run bin/setup to install dependencies. 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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/yuya-takeyama/flagship.

License

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