Class: Optimizely::DecisionService

Inherits:
Object
  • Object
show all
Defined in:
lib/optimizely/decision_service.rb

Defined Under Namespace

Classes: Decision

Constant Summary collapse

DECISION_SOURCES = 
{
  'EXPERIMENT' => 'experiment',
  'FEATURE_TEST' => 'feature-test',
  'ROLLOUT' => 'rollout'
}.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(logger, user_profile_service = nil) ⇒ DecisionService

Returns a new instance of DecisionService.



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# File 'lib/optimizely/decision_service.rb', line 48

def initialize(logger,  = nil)
  @logger = logger
  @user_profile_service = 
  @bucketer = Bucketer.new(logger)
  @forced_variation_map = {}
end

Instance Attribute Details

#bucketer ⇒ Object (readonly)

Optimizely’s decision service that determines into which variation of an experiment a user will be allocated.

The decision service contains all logic relating to how a user bucketing decisions is made. This includes all of the following (in order):

  1. Check experiment status

  2. Check forced bucketing

  3. Check whitelisting

  4. Check user profile service for past bucketing decisions (sticky bucketing)

  5. Check audience targeting

  6. Use Murmurhash3 to bucket the user



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# File 'lib/optimizely/decision_service.rb', line 34

def bucketer
  @bucketer
end

#forced_variation_map ⇒ Object (readonly)

Hash of user IDs to a Hash of experiments to variations. This contains all the forced variations set by the user by calling setForcedVariation.



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# File 'lib/optimizely/decision_service.rb', line 38

def forced_variation_map
  @forced_variation_map
end

Instance Method Details

#get_forced_variation(project_config, experiment_key, user_id) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 374

def get_forced_variation(project_config, experiment_key, user_id)
  # Gets the forced variation for the given user and experiment.
  #
  # project_config - Instance of ProjectConfig
  # experiment_key - String key for experiment
  # user_id - String ID for user
  #
  # Returns Variation The variation which the given user and experiment should be forced into

  decide_reasons = []
  unless @forced_variation_map.key? user_id
    message = "User '#{user_id}' is not in the forced variation map."
    @logger.log(Logger::DEBUG, message)
    return nil, decide_reasons
  end

  experiment_to_variation_map = @forced_variation_map[user_id]
  experiment = project_config.get_experiment_from_key(experiment_key)
  experiment_id = experiment['id'] if experiment
  # check for nil and empty string experiment ID
  # this case is logged in get_experiment_from_key
  return nil, decide_reasons if experiment_id.nil? || experiment_id.empty?

  unless experiment_to_variation_map.key? experiment_id
    message = "No experiment '#{experiment_id}' mapped to user '#{user_id}' in the forced variation map."
    @logger.log(Logger::DEBUG, message)
    decide_reasons.push(message)
    return nil, decide_reasons
  end

  variation_id = experiment_to_variation_map[experiment_id]
  variation_key = ''
  variation = project_config.get_variation_from_id_by_experiment_id(experiment_id, variation_id)
  variation_key = variation['key'] if variation

  # check if the variation exists in the datafile
  # this case is logged in get_variation_from_id
  return nil, decide_reasons if variation_key.empty?

  message = "Variation '#{variation_key}' is mapped to experiment '#{experiment_id}' and user '#{user_id}' in the forced variation map"
  @logger.log(Logger::DEBUG, message)
  decide_reasons.push(message)

  [variation, decide_reasons]
end

#get_variation(project_config, experiment_id, user_context, decide_options = []) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 55

def get_variation(project_config, experiment_id, user_context, decide_options = [])
  # Determines variation into which user will be bucketed.
  #
  # project_config - project_config - Instance of ProjectConfig
  # experiment_id - Experiment for which visitor variation needs to be determined
  # user_context - Optimizely user context instance
  #
  # Returns variation ID where visitor will be bucketed
  #   (nil if experiment is inactive or user does not meet audience conditions)

  decide_reasons = []
  user_id = user_context.user_id
  attributes = user_context.user_attributes
  # By default, the bucketing ID should be the user ID
  bucketing_id, bucketing_id_reasons = get_bucketing_id(user_id, attributes)
  decide_reasons.push(*bucketing_id_reasons)
  # Check to make sure experiment is active
  experiment = project_config.get_experiment_from_id(experiment_id)
  return nil, decide_reasons if experiment.nil?

  experiment_key = experiment['key']
  unless project_config.experiment_running?(experiment)
    message = "Experiment '#{experiment_key}' is not running."
    @logger.log(Logger::INFO, message)
    decide_reasons.push(message)
    return nil, decide_reasons
  end

  # Check if a forced variation is set for the user
  forced_variation, reasons_received = get_forced_variation(project_config, experiment['key'], user_id)
  decide_reasons.push(*reasons_received)
  return forced_variation['id'], decide_reasons if forced_variation

  # Check if user is in a white-listed variation
  whitelisted_variation_id, reasons_received = get_whitelisted_variation_id(project_config, experiment_id, user_id)
  decide_reasons.push(*reasons_received)
  return whitelisted_variation_id, decide_reasons if whitelisted_variation_id

   = decide_options.include? Optimizely::Decide::OptimizelyDecideOption::IGNORE_USER_PROFILE_SERVICE
  # Check for saved bucketing decisions if decide_options do not include ignoreUserProfileService
  unless 
    , reasons_received = (user_id)
    decide_reasons.push(*reasons_received)
    saved_variation_id, reasons_received = get_saved_variation_id(project_config, experiment_id, )
    decide_reasons.push(*reasons_received)
    if saved_variation_id
      message = "Returning previously activated variation ID #{saved_variation_id} of experiment '#{experiment_key}' for user '#{user_id}' from user profile."
      @logger.log(Logger::INFO, message)
      decide_reasons.push(message)
      return saved_variation_id, decide_reasons
    end
  end

  # Check audience conditions
  user_meets_audience_conditions, reasons_received = Audience.user_meets_audience_conditions?(project_config, experiment, user_context, @logger)
  decide_reasons.push(*reasons_received)
  unless user_meets_audience_conditions
    message = "User '#{user_id}' does not meet the conditions to be in experiment '#{experiment_key}'."
    @logger.log(Logger::INFO, message)
    decide_reasons.push(message)
    return nil, decide_reasons
  end

  # Bucket normally
  variation, bucket_reasons = @bucketer.bucket(project_config, experiment, bucketing_id, user_id)
  decide_reasons.push(*bucket_reasons)
  variation_id = variation ? variation['id'] : nil

  message = ''
  if variation_id
    variation_key = variation['key']
    message = "User '#{user_id}' is in variation '#{variation_key}' of experiment '#{experiment_id}'."
  else
    message = "User '#{user_id}' is in no variation."
  end
  @logger.log(Logger::INFO, message)
  decide_reasons.push(message)

  # Persist bucketing decision
  (, experiment_id, variation_id) unless 
  [variation_id, decide_reasons]
end

#get_variation_for_feature(project_config, feature_flag, user_context, decide_options = []) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 138

def get_variation_for_feature(project_config, feature_flag, user_context, decide_options = [])
  # Get the variation the user is bucketed into for the given FeatureFlag.
  #
  # project_config - project_config - Instance of ProjectConfig
  # feature_flag - The feature flag the user wants to access
  # user_context - Optimizely user context instance
  #
  # Returns Decision struct (nil if the user is not bucketed into any of the experiments on the feature)

  decide_reasons = []

  # check if the feature is being experiment on and whether the user is bucketed into the experiment
  decision, reasons_received = get_variation_for_feature_experiment(project_config, feature_flag, user_context, decide_options)
  decide_reasons.push(*reasons_received)
  return decision, decide_reasons unless decision.nil?

  decision, reasons_received = get_variation_for_feature_rollout(project_config, feature_flag, user_context)
  decide_reasons.push(*reasons_received)

  [decision, decide_reasons]
end

#get_variation_for_feature_experiment(project_config, feature_flag, user_context, decide_options = []) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 160

def get_variation_for_feature_experiment(project_config, feature_flag, user_context, decide_options = [])
  # Gets the variation the user is bucketed into for the feature flag's experiment.
  #
  # project_config - project_config - Instance of ProjectConfig
  # feature_flag - The feature flag the user wants to access
  # user_context - Optimizely user context instance
  #
  # Returns Decision struct (nil if the user is not bucketed into any of the experiments on the feature)
  # or nil if the user is not bucketed into any of the experiments on the feature
  decide_reasons = []
  user_id = user_context.user_id
  feature_flag_key = feature_flag['key']
  if feature_flag['experimentIds'].empty?
    message = "The feature flag '#{feature_flag_key}' is not used in any experiments."
    @logger.log(Logger::DEBUG, message)
    decide_reasons.push(message)
    return nil, decide_reasons
  end

  # Evaluate each experiment and return the first bucketed experiment variation
  feature_flag['experimentIds'].each do |experiment_id|
    experiment = project_config.experiment_id_map[experiment_id]
    unless experiment
      message = "Feature flag experiment with ID '#{experiment_id}' is not in the datafile."
      @logger.log(Logger::DEBUG, message)
      decide_reasons.push(message)
      return nil, decide_reasons
    end

    experiment_id = experiment['id']
    variation_id, reasons_received = get_variation_from_experiment_rule(project_config, feature_flag_key, experiment, user_context, decide_options)
    decide_reasons.push(*reasons_received)

    next unless variation_id

    variation = project_config.get_variation_from_id_by_experiment_id(experiment_id, variation_id)
    variation = project_config.get_variation_from_flag(feature_flag['key'], variation_id, 'id') if variation.nil?

    return Decision.new(experiment, variation, DECISION_SOURCES['FEATURE_TEST']), decide_reasons
  end

  message = "The user '#{user_id}' is not bucketed into any of the experiments on the feature '#{feature_flag_key}'."
  @logger.log(Logger::INFO, message)
  decide_reasons.push(message)

  [nil, decide_reasons]
end

#get_variation_for_feature_rollout(project_config, feature_flag, user_context) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 208

def get_variation_for_feature_rollout(project_config, feature_flag, user_context)
  # Determine which variation the user is in for a given rollout.
  # Returns the variation of the first experiment the user qualifies for.
  #
  # project_config - project_config - Instance of ProjectConfig
  # feature_flag - The feature flag the user wants to access
  # user_context - Optimizely user context instance
  #
  # Returns the Decision struct or nil if not bucketed into any of the targeting rules
  decide_reasons = []

  rollout_id = feature_flag['rolloutId']
  feature_flag_key = feature_flag['key']
  if rollout_id.nil? || rollout_id.empty?
    message = "Feature flag '#{feature_flag_key}' is not used in a rollout."
    @logger.log(Logger::DEBUG, message)
    decide_reasons.push(message)
    return nil, decide_reasons
  end

  rollout = project_config.get_rollout_from_id(rollout_id)
  if rollout.nil?
    message = "Rollout with ID '#{rollout_id}' is not in the datafile '#{feature_flag['key']}'"
    @logger.log(Logger::DEBUG, message)
    decide_reasons.push(message)
    return nil, decide_reasons
  end

  return nil, decide_reasons if rollout['experiments'].empty?

  index = 0
  rollout_rules = rollout['experiments']
  while index < rollout_rules.length
    variation, skip_to_everyone_else, reasons_received = get_variation_from_delivery_rule(project_config, feature_flag_key, rollout_rules, index, user_context)
    decide_reasons.push(*reasons_received)
    if variation
      rule = rollout_rules[index]
      feature_decision = Decision.new(rule, variation, DECISION_SOURCES['ROLLOUT'])
      return [feature_decision, decide_reasons]
    end

    index = skip_to_everyone_else ? (rollout_rules.length - 1) : (index + 1)
  end

  [nil, decide_reasons]
end

#get_variation_from_delivery_rule(project_config, flag_key, rules, rule_index, user_context) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 279

def get_variation_from_delivery_rule(project_config, flag_key, rules, rule_index, user_context)
  # Determine which variation the user is in for a given rollout.
  # Returns the variation from delivery rules.
  #
  # project_config - project_config - Instance of ProjectConfig
  # flag_key - The feature flag the user wants to access
  # rule - An experiment rule key
  # user_context - Optimizely user context instance
  #
  # Returns variation, boolean to skip for eveyone else rule and reasons
  reasons = []
  skip_to_everyone_else = false
  rule = rules[rule_index]
  context = Optimizely::OptimizelyUserContext::OptimizelyDecisionContext.new(flag_key, rule['key'])
  variation, forced_reasons = validated_forced_decision(project_config, context, user_context)
  reasons.push(*forced_reasons)

  return [variation, skip_to_everyone_else, reasons] if variation

  user_id = user_context.user_id
  attributes = user_context.user_attributes
  bucketing_id, bucketing_id_reasons = get_bucketing_id(user_id, attributes)
  reasons.push(*bucketing_id_reasons)

  everyone_else = (rule_index == rules.length - 1)

  logging_key = everyone_else ? 'Everyone Else' : (rule_index + 1).to_s

  user_meets_audience_conditions, reasons_received = Audience.user_meets_audience_conditions?(project_config, rule, user_context, @logger, 'ROLLOUT_AUDIENCE_EVALUATION_LOGS', logging_key)
  reasons.push(*reasons_received)
  unless user_meets_audience_conditions
    message = "User '#{user_id}' does not meet the conditions for targeting rule '#{logging_key}'."
    @logger.log(Logger::DEBUG, message)
    reasons.push(message)
    return [nil, skip_to_everyone_else, reasons]
  end

  message = "User '#{user_id}' meets the audience conditions for targeting rule '#{logging_key}'."
  @logger.log(Logger::DEBUG, message)
  reasons.push(message)
  bucket_variation, bucket_reasons = @bucketer.bucket(project_config, rule, bucketing_id, user_id)

  reasons.push(*bucket_reasons)

  if bucket_variation
    message = "User '#{user_id}' is in the traffic group of targeting rule '#{logging_key}'."
    @logger.log(Logger::DEBUG, message)
    reasons.push(message)
  elsif !everyone_else
    message = "User '#{user_id}' is not in the traffic group for targeting rule '#{logging_key}'."
    @logger.log(Logger::DEBUG, message)
    reasons.push(message)
    skip_to_everyone_else = true
  end
  [bucket_variation, skip_to_everyone_else, reasons]
end

#get_variation_from_experiment_rule(project_config, flag_key, rule, user, options = []) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 255

def get_variation_from_experiment_rule(project_config, flag_key, rule, user, options = [])
  # Determine which variation the user is in for a given rollout.
  # Returns the variation from experiment rules.
  #
  # project_config - project_config - Instance of ProjectConfig
  # flag_key - The feature flag the user wants to access
  # rule - An experiment rule key
  # user - Optimizely user context instance
  #
  # Returns variation_id and reasons
  reasons = []

  context = Optimizely::OptimizelyUserContext::OptimizelyDecisionContext.new(flag_key, rule['key'])
  variation, forced_reasons = validated_forced_decision(project_config, context, user)
  reasons.push(*forced_reasons)

  return [variation['id'], reasons] if variation

  variation_id, response_reasons = get_variation(project_config, rule['id'], user, options)
  reasons.push(*response_reasons)

  [variation_id, reasons]
end

#set_forced_variation(project_config, experiment_key, user_id, variation_key) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 336

def set_forced_variation(project_config, experiment_key, user_id, variation_key)
  # Sets a Hash of user IDs to a Hash of experiments to forced variations.
  #
  # project_config - Instance of ProjectConfig
  # experiment_key - String Key for experiment
  # user_id - String ID for user.
  # variation_key - String Key for variation. If null, then clear the existing experiment-to-variation mapping
  #
  # Returns a boolean value that indicates if the set completed successfully

  experiment = project_config.get_experiment_from_key(experiment_key)
  experiment_id = experiment['id'] if experiment
  #  check if the experiment exists in the datafile
  return false if experiment_id.nil? || experiment_id.empty?

  #  clear the forced variation if the variation key is null
  if variation_key.nil?
    @forced_variation_map[user_id].delete(experiment_id) if @forced_variation_map.key? user_id
    @logger.log(Logger::DEBUG, "Variation mapped to experiment '#{experiment_key}' has been removed for user "\
                "'#{user_id}'.")
    return true
  end

  variation_id = project_config.get_variation_id_from_key_by_experiment_id(experiment_id, variation_key)

  #  check if the variation exists in the datafile
  unless variation_id
    #  this case is logged in get_variation_id_from_key
    return false
  end

  @forced_variation_map[user_id] = {} unless @forced_variation_map.key? user_id
  @forced_variation_map[user_id][experiment_id] = variation_id
  @logger.log(Logger::DEBUG, "Set variation '#{variation_id}' for experiment '#{experiment_id}' and "\
              "user '#{user_id}' in the forced variation map.")
  true
end

#validated_forced_decision(project_config, context, user_context) ⇒ Object 



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# File 'lib/optimizely/decision_service.rb', line 420

def validated_forced_decision(project_config, context, user_context)
  decision = user_context.get_forced_decision(context)
  flag_key = context[:flag_key]
  rule_key = context[:rule_key]
  variation_key = decision ? decision[:variation_key] : decision
  reasons = []
  target = rule_key ? "flag (#{flag_key}), rule (#{rule_key})" : "flag (#{flag_key})"
  if variation_key
    variation = project_config.get_variation_from_flag(flag_key, variation_key, 'key')
    if variation
      reason = "Variation (#{variation_key}) is mapped to #{target} and user (#{user_context.user_id}) in the forced decision map."
      reasons.push(reason)
      return variation, reasons
    else
      reason = "Invalid variation is mapped to #{target} and user (#{user_context.user_id}) in the forced decision map."
      reasons.push(reason)
    end
  end

  [nil, reasons]
end