Class: Vanity::Experiment::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/vanity/experiment/base.rb

Overview

Base class that all experiment types are derived from.

Direct Known Subclasses

AbTest

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(playground, id, name, options = nil) ⇒ Base

Returns a new instance of Base.


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# File 'lib/vanity/experiment/base.rb', line 38

def initialize(playground, id, name, options = nil)
  @playground = playground
  @id = id.to_sym
  @name = name
  @options = options || {}
  @identify_block = method(:default_identify)
  @on_assignment_block = nil
end

Instance Attribute Details

#idObject (readonly)

Unique identifier, derived from name experiment name, e.g. “Green Button” becomes :green_button.


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# File 'lib/vanity/experiment/base.rb', line 54

def id
  @id
end

#nameObject (readonly) Also known as: to_s

Human readable experiment name (first argument you pass when creating a new experiment).


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# File 'lib/vanity/experiment/base.rb', line 49

def name
  @name
end

#playgroundObject (readonly)

Returns the value of attribute playground.


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# File 'lib/vanity/experiment/base.rb', line 56

def playground
  @playground
end

Class Method Details

.load(playground, stack, file) ⇒ Object

Playground uses this to load experiment definitions.


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# File 'lib/vanity/experiment/base.rb', line 15

def load(playground, stack, file)
  raise "Circular dependency detected: #{stack.join('=>')}=>#{file}" if stack.include?(file)

  source = File.read(file)
  stack.push file
  id = File.basename(file, ".rb").downcase.gsub(/\W/, "_").to_sym
  context = Object.new
  context.instance_eval do
    extend Definition
    experiment = eval(source, context.new_binding(playground, id), file) # rubocop:todo Security/Eval
    raise NameError.new("Expected #{file} to define experiment #{id}", id) unless playground.experiments[id]

    return experiment
  end
rescue StandardError
  error = NameError.exception($!.message, id)
  error.set_backtrace $!.backtrace
  raise error
ensure
  stack.pop
end

.typeObject

Returns the type of this class as a symbol (e.g. AbTest becomes ab_test).


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# File 'lib/vanity/experiment/base.rb', line 10

def type
  name.split("::").last.gsub(/([a-z])([A-Z])/) { "#{Regexp.last_match(1)}_#{Regexp.last_match(2)}" }.gsub(/([A-Z])([A-Z][a-z])/) { "#{Regexp.last_match(1)}_#{Regexp.last_match(2)}" }.downcase
end

Instance Method Details

#active?Boolean

Returns true if experiment active, false if completed.

Returns:

  • (Boolean)

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# File 'lib/vanity/experiment/base.rb', line 145

def active?
  !@playground.collecting? || !connection.is_experiment_completed?(@id)
end

#complete!(_outcome = nil) ⇒ Object

Force experiment to complete. outcome of the experiment

Parameters:

  • optional

    integer id of the alternative that is the decided


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# File 'lib/vanity/experiment/base.rb', line 131

def complete!(_outcome = nil)
  @playground.logger.info "vanity: completed experiment #{id}"
  return unless @playground.collecting?

  connection.set_experiment_completed_at @id, Time.now
  @completed_at = connection.get_experiment_completed_at(@id)
end

#complete_if(&block) ⇒ Object

Define experiment completion condition. For example:

complete_if do
  !score(95).chosen.nil?
end

Raises:

  • (ArgumentError)

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# File 'lib/vanity/experiment/base.rb', line 121

def complete_if(&block)
  raise ArgumentError, "Missing block" unless block
  raise "complete_if already called on this experiment" if defined?(@complete_block)

  @complete_block = block
end

#completed_atObject

Time stamp when experiment was completed.


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# File 'lib/vanity/experiment/base.rb', line 140

def completed_at
  @completed_at ||= connection.get_experiment_completed_at(@id)
end

#created_atObject

Time stamp when experiment was created.


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# File 'lib/vanity/experiment/base.rb', line 59

def created_at
  @created_at ||= connection.get_experiment_created_at(@id)
end

#description(text = nil) ⇒ Object

Sets or returns description. For example

ab_test "Simple" do
  description "A simple A/B experiment"
end

puts "Just defined: " + experiment(:simple).description

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# File 'lib/vanity/experiment/base.rb', line 110

def description(text = nil)
  @description = text if text
  @description if defined?(@description)
end

#destroyObject

Get rid of all experiment data.


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# File 'lib/vanity/experiment/base.rb', line 152

def destroy
  connection.destroy_experiment @id
  @created_at = @completed_at = nil
end

#identify(&block) ⇒ Object

Defines how we obtain an identity for the current experiment. Usually Vanity gets the identity form a session object (see use_vanity), but there are cases where you want a particular experiment to use a different identity.

For example, if all your experiments use current_user and you need one experiment to use the current project:

ab_test "Project widget" do
  alternatives :small, :medium, :large
  identify do |controller|
    controller.project.id
  end
end

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# File 'lib/vanity/experiment/base.rb', line 81

def identify(&block)
  raise "Missing block" unless block

  @identify_block = block
end

#on_assignment(&block) ⇒ Object

Defines any additional actions to take when a new assignment is made for the current experiment

For example, if you want to use the rails default logger to log whenever an assignment is made:

ab_test "Project widget" do
  alternatives :small, :medium, :large
  on_assignment do |controller, identity, assignment|
    controller.logger.info "made a split test assignment for #{experiment.name}: #{identity} => #{assignment}"
  end
end

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# File 'lib/vanity/experiment/base.rb', line 96

def on_assignment(&block)
  raise "Missing block" unless block

  @on_assignment_block = block
end

#reject(&block) ⇒ Object

Define an experiment specific request filter. For example:

reject do |request|
  true if Vanity.context.cookies["somecookie"]
end

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# File 'lib/vanity/experiment/base.rb', line 172

def reject(&block)
  raise "Missing block" unless block
  raise "filter already called on this experiment" if @request_filter_block

  @request_filter_block = block
end

#saveObject

Called by Playground to save the experiment definition.


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# File 'lib/vanity/experiment/base.rb', line 158

def save
  return unless @playground.collecting?

  connection.set_experiment_created_at @id, Time.now
end

#typeObject

Returns the type of this experiment as a symbol (e.g. :ab_test).


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# File 'lib/vanity/experiment/base.rb', line 64

def type
  self.class.type
end