Brollout

Inspired by James Golick's rollout, brollout makes it easy to turn features on and off in your application. You can disable a feature if you need to run a site in degraded mode, you can turn a feature on for a percentage of your users, or you can ramp a feature up by percentage of requests when you're testing new infrastructure.

This is just a sketch. Don't rage me, bro.

Bro! Show me that code

# Store feature flags in Redis
Brollout.adapter = Brollout::Adapter.new

$friend_finder = Brollout.feature(:friend_finder, :on_off)
$new_cache = Brollout.feature(:new_cache, :per_request_percentage)

Brollout.register_strategy(:custom) do |user|
  user.admin? || per_user_percentage(user)
end

$better_sharing = Brollout.feature(:better_sharing, :custom)

$simple = Brollout.feature(:simple, :on_off, Brollout::InMemory.new)
$simple.activate!

if $simple.active?
  # Do friend finder things
else
  # Do something else
end

$new_cache.activate_for(0.5)

if $new_cache.active?
  # Use the new cache
else
  # Use the old cache
end

$better_sharing.activate_for(user)

if $better_sharing.active?(user.id)
  # Show the new feature
else
  # Show the old feature
end

Bro, how do I toggle and can I toggle my own toggle?

Brollout ships with the following toggle strategies:

• On/off
• Random percentage
• Per object ID
• Object ID modulo

In addition, you can implement your own toggle strategies by using the register_strategy:

Brollout.register_strategy(:custom) do |user|
  user.admin? || per_user_percentage(user)
end

Pretty snazzy, no?

Bro, you can stick it wherever you stick things

Brollout ships with adapters to store feature flags in per-process memory, memcached, redis, or wherever it is you like to store things. Adapters implement the following contract:

adapter.on_off?(feature)
adapter.per_object_id(feature)

Bro, can I license that thing?

Yep! Brollout is copyright 2011 Adam Keys. Brollout is MIT licensed, so go crazy, bro.