Vanity

Vanity is an A/B testing framework for Rails that is datastore agnostic.

• All about Vanity: http://vanity.labnotes.org
• On Github: http://github.com/assaf/vanity

• Installation
• Setup
  • Datastore
    • Redis Setup
    • MongoDB Setup
    • SQL Database Setup
    • Forking servers and reconnecting
  • Initialization
  • User identification
    • Rails
    • Other
  • Define a A/B test
  • Present the different options to your users
  • Measure conversion
  • Check the report
    • Rails report dashboard
• Registering participants with Javascript
• Compatibility
• Testing
• Updating documentation
• Contributing
• Credits/License

Installation

Add to your Gemfile:

gem "vanity"

(For support for older versions of Rails and Ruby 1.8, please see the 1.9.x branch.)

Setup

Datastore

Choose a datastore that best fits your needs and preferences for storing experiment results. Choose one of: Redis, MongoDB or an SQL database. While Redis is usually faster, it may add additional complexity to your stack. Datastores should be configured using a config/vanity.yml.

Redis Setup

Add to your Gemfile:

gem "redis", ">= 3.2"
gem "redis-namespace", ">= 1.1.0"

By default Vanity is configured to use Redis on localhost port 6379 with database 0.

A sample config/vanity.yml might look like:

test:
  collecting: false
production:
  adapter: redis
  url: redis://<%= ENV["REDIS_USER"] %>:<%= ENV["REDIS_PASSWORD"] %>@<%= ENV["REDIS_HOST"] %>:<%= ENV["REDIS_PORT"] %>/0

If you want to use your test environment with RSpec you will need to add an adapter to test:

test:
  adapter: redis
  collecting: false

To re-use an existing redis connection, you can call Vanity.connect! explicitly, for example:

Vanity.connect!(
  adapter: :redis,
  redis: $redis
)

MongoDB Setup

Add to your Gemfile:

gem "mongo", "~> 2.0" # For Mongo 1.x support see Vanity versions 2.1 and below.

A sample config/vanity.yml might look like:

development:
  adapter: mongodb
  database: analytics
test:
  collecting: false
production:
  adapter: mongodb
  database: analytics

SQL Database Setup

Vanity supports multiple SQL stores (like MySQL, MariaDB, Postgres, Sqlite, etc.) using ActiveRecord, which is built into Rails. If you're using DataMapper, Sequel or another persistence framework, add to your Gemfile:

    gem "active_record"

A sample config/vanity.yml might look like:

development:
  adapter: active_record
  active_record_adapter: sqlite3
  database: db/development.sqlite3
test:
  adapter: active_record
  active_record_adapter: default
  collecting: false
production:
  adapter: active_record
  active_record_adapter: postgresql
  <% uri = URI.parse(ENV['DATABASE_URL']) %>
  host:     <%= uri.host %>
  username: <%= uri.user%>
  password: <%= uri.password %>
  port:     <%= uri.port %>
  database: <%= uri.path.sub('/', '') %>

If you're going to store data in the database, run the generator and migrations to create the database schema:

$ rails generate vanity
$ rake db:migrate

Forking servers and reconnecting

If you're using a forking server (like Passenger or Unicorn), you should reconnect after a new worker is created:

# unicorn.rb
after_fork do |server, worker|
  defined?(Vanity) && Vanity.reconnect!
end

# an initializer
if defined?(PhusionPassenger)
  PhusionPassenger.on_event(:starting_worker_process) do |forked|
    # We're in smart spawning mode.
    if forked
      defined?(Vanity) && Vanity.reconnect!
    end
  end
end

If you're using explicit options with Vanity.connect!, you should call disconnect! first, for example:

Vanity.disconnect!
Vanity.connect!(
  adapter: 'redis',
  redis: $redis
)

Initialization

If you're using Rails, this is done automagically. Otherwise, some manual setup is required, for example on an app's booting:

$redis = Redis.new # or from elsewhere
Vanity.configure do |config|
  # ... any config
end
Vanity.connect!(
  adapter: :redis,
  redis: $redis
)
Vanity.load!

User identification

Rails

Turn Vanity on, and pass a reference to a method that identifies a user. For example:

class ApplicationController < ActionController::Base
  use_vanity :current_user
end

For more information, please see the identity documentation.

Other

Vanity pulls the identity from a "context" object that responds to vanity_identity, so we need to define a Vanity.context (this is how the ActionMailer integration works):

class AVanityContext
  def vanity_identity
    "123"
  end
end

Vanity.context = AVanityContext.new() # Any object that responds to `#vanity_identity`

If you're using plain ruby objects, you could also alias something in your identity model to respond similarly and then set that as the vanity context:

class User
  alias_method :vanity_identity, :id
end

Define a A/B test

This experiment goes in the file experiments/price_options.rb:

ab_test "Price options" do
  description "Mirror, mirror on the wall, who's the better price of all?"
  alternatives 19, 25, 29
  metrics :signups
end

If the experiment uses a metric as above ("signups"), there needs to be a corresponding ruby file for that metric, experiments/metrics/signups.rb.

metric "Signup (Activation)" do
  description "Measures how many people signed up for our awesome service."
end

Present the different options to your users

In Rails' templates, this is straightforward:

<h2>Get started for only $<%= ab_test :price_options %> a month!</h2>

Outside of templates:

Vanity.ab_test(:invite_subject)

Measure conversion

Conversions are created via the Vanity.track! method. A user should already be added to an experiment, via ab_test before this is called - otherwise, the conversion will be tracked, but the user will not be added to the experiment.

For example, in Rails:

class SignupController < ApplicationController
  def signup
    @account = Account.new(params[:account])
    if @account.save
      Vanity.track!(:signups)
      redirect_to @acccount
    else
      render action: :offer
    end
  end
end

Outside of an Rails controller, for example in a Rack handler:

identity_object = Identity.new(env['rack.session'])
Vanity.track!(:click, {
  # can be any object that responds to `to_s` with a string
  # that contains the unique identifier or the string identifier itself
  :identity=>identity_object,
  :values=>[1] # optional
})

Check the report

vanity report --output vanity.html

Rails report dashboard

To view metrics and experiment results with the dashboard in Rails 3 & Rails 4:

rails generate controller Vanity --helper=false

In config/routes.rb, add:

get '/vanity' =>'vanity#index'
get '/vanity/participant/:id' => 'vanity#participant'
post '/vanity/complete'
post '/vanity/chooses'
post '/vanity/reset'
post '/vanity/enable'
post '/vanity/disable'
post '/vanity/add_participant'
get '/vanity/image'

The controller should look like:

class VanityController < ApplicationController
  include Vanity::Rails::Dashboard
  layout false  # exclude this if you want to use your application layout
end

Registering participants with Javascript

If robots or spiders make up a significant portion of your sites traffic they can affect your conversion rate. Vanity can optionally add participants to the experiments using asynchronous javascript callbacks, which will keep many robots out. For those robots that do execute Javascript and are well-behaved (like Googlebot), Vanity filters out requests based on their user-agent string.

In Rails, add the following to application.rb:

Vanity.configure do |config|
  config.use_js = true

  # Optionally configure the add_participant route that is added with Vanity::Rails::Dashboard,
  # make sure that this action does not require authentication
  # config.add_participant_route = '/vanity/add_participant'
end

Then add <%= vanity_js %> to any page that calls an A/B test after calling ab_test. vanity_js needs to be included after your call to ab_test so that it knows which version of the experiment the participant is a member of. The helper will render nothing if the there are no ab_tests running on the current page, so adding vanity_js to the bottom of your layouts is a good option. Keep in mind that if you set use_js and don't include vanity_js in your view no participants will be recorded.

Compatibility

Here's what's tested and known to work:

Rails: 5.2+
Ruby: 2.5+
JRuby: 9.1+
Persistence: Redis (redis-rb >= 3.2.1), Mongo, ActiveRecord

Testing

For view tests/specs or integration testing, it's handy to set the outcome of an experiment. This may be done using the chooses method. For example:

Vanity.playground.experiment(:price_options).chooses(19)

See the docs on testing for more.

Updating documentation

Documenation is written in the textile format in the docs directory, and is hosted on Github Pages. To update the docs commit changes to the master branch in this repository, then:

bundle exec rake docs # output HTML files into html/
git checkout gh-pages
mv html/* . # Move generated html to the top of the repo
git commit # Add, commit and push any changes!

Go ahead and target a pull request against the gh-pages branch.

Contributing

• Fork the project
• Please use a feature branch to make your changes, it's easier to test them that way
• To set up the test suite run bundle, then run appraisal install to prepare the test suite to run against multiple versions of Rails
• Fix, patch, enhance, document, improve, sprinkle pixie dust
• Tests. Please. Run appraisal rake test, of if you can, rake test:all. (This project uses Github Actions where the test suite is run against multiple versions of ruby, rails and backends.)
• Send a pull request on GitHub

Credits/License

Original code, copyright of Assaf Arkin, released under the MIT license.

Documentation available under the Creative Commons Attribution license.

For full list of credits and licenses: http://vanity.labnotes.org/credits.html.