feat(DecisionListener): Adds feature decision listener.

optimizely/decision_service.py

@@ -22,8 +22,8 @@
 from .user_profile import UserProfile
 
 Decision = namedtuple('Decision', 'experiment variation source')
-DECISION_SOURCE_EXPERIMENT = 'experiment'
-DECISION_SOURCE_ROLLOUT = 'rollout'
+DECISION_SOURCE_EXPERIMENT = 'EXPERIMENT'
+DECISION_SOURCE_ROLLOUT = 'ROLLOUT'
 
 
 class DecisionService(object):
@@ -296,6 +296,7 @@ def get_variation_for_feature(self, feature, user_id, attributes=None):
               variation.key,
               experiment.key
             ))
+            return Decision(experiment, variation, DECISION_SOURCE_EXPERIMENT)
       else:
         self.logger.error(enums.Errors.INVALID_GROUP_ID_ERROR.format('_get_variation_for_feature'))
 
@@ -312,10 +313,11 @@ def get_variation_for_feature(self, feature, user_id, attributes=None):
             variation.key,
             experiment.key
           ))
+          return Decision(experiment, variation, DECISION_SOURCE_EXPERIMENT)
 
     # Next check if user is part of a rollout
-    if not variation and feature.rolloutId:
+    if feature.rolloutId:
       rollout = self.config.get_rollout_from_id(feature.rolloutId)
       return self.get_variation_for_rollout(rollout, user_id, attributes)
-
-    return Decision(experiment, variation, DECISION_SOURCE_EXPERIMENT)
+    else:
+      return Decision(None, None, DECISION_SOURCE_ROLLOUT)

optimizely/helpers/enums.py

@@ -93,9 +93,10 @@ class NotificationTypes(object):
       DecisionInfoTypes type, str user_id, dict attributes (can be None), dict decision_info
   """
   ACTIVATE = "ACTIVATE:experiment, user_id, attributes, variation, event"
+  DECISION = "DECISION:type, user_id, attributes, decision_info"
   TRACK = "TRACK:event_key, user_id, attributes, event_tags, event"
-  DECISION = "DECISON:type, user_id, attributes, decision_info"
 
 
 class DecisionInfoTypes(object):
-  EXPERIMENT = "experiment"
+    EXPERIMENT = "experiment"
+    FEATURE = "feature"

optimizely/optimizely.py

@@ -409,21 +409,44 @@ def is_feature_enabled(self, feature_key, user_id, attributes=None):
     if not feature:
       return False
 
+    experiment_key = None
+    feature_enabled = False
+    variation_key = None
     decision = self.decision_service.get_variation_for_feature(feature, user_id, attributes)
+    is_source_experiment = decision.source == decision_service.DECISION_SOURCE_EXPERIMENT
+
     if decision.variation:
+      if decision.variation.featureEnabled is True:
+        feature_enabled = True
       # Send event if Decision came from an experiment.
-      if decision.source == decision_service.DECISION_SOURCE_EXPERIMENT:
+      if is_source_experiment:
+        experiment_key = decision.experiment.key
+        variation_key = decision.variation.key
         self._send_impression_event(decision.experiment,
                                     decision.variation,
                                     user_id,
                                     attributes)
 
-      if decision.variation.featureEnabled:
-        self.logger.info('Feature "%s" is enabled for user "%s".' % (feature_key, user_id))
-        return True
+    if feature_enabled:
+      self.logger.info('Feature "%s" is enabled for user "%s".' % (feature_key, user_id))
+    else:
+      self.logger.info('Feature "%s" is not enabled for user "%s".' % (feature_key, user_id))
+
+    self.notification_center.send_notifications(
+        enums.NotificationTypes.DECISION,
+        enums.DecisionInfoTypes.FEATURE,
+        user_id,
+        attributes or {},
+        {
+          'feature_key': feature_key,
+          'feature_enabled': feature_enabled,
+          'source': decision.source,
+          'source_experiment_key': experiment_key,
+          'source_variation_key': variation_key
+        }
+    )
 
-    self.logger.info('Feature "%s" is not enabled for user "%s".' % (feature_key, user_id))
-    return False
+    return feature_enabled
 
   def get_enabled_features(self, user_id, attributes=None):
     """ Returns the list of features that are enabled for the user.

tests/test_decision_service.py

@@ -637,7 +637,7 @@ def test_get_variation_for_feature__returns_none_for_user_not_in_group(self):
     with mock.patch('optimizely.decision_service.DecisionService.get_experiment_in_group',
                     return_value=None) as mock_get_experiment_in_group, \
       mock.patch('optimizely.decision_service.DecisionService.get_variation') as mock_decision:
-      self.assertEqual(decision_service.Decision(None, None, decision_service.DECISION_SOURCE_EXPERIMENT),
+      self.assertEqual(decision_service.Decision(None, None, decision_service.DECISION_SOURCE_ROLLOUT),
                        self.decision_service.get_variation_for_feature(feature, 'test_user'))
 
     mock_get_experiment_in_group.assert_called_once_with(self.project_config.get_group('19228'), 'test_user')
@@ -647,12 +647,11 @@ def test_get_variation_for_feature__returns_none_for_user_not_in_experiment(self
     """ Test that get_variation_for_feature returns None for user not in the associated experiment. """
 
     feature = self.project_config.get_feature_from_key('test_feature_in_experiment')
-    expected_experiment = self.project_config.get_experiment_from_key('test_experiment')
 
     with mock.patch('optimizely.decision_service.DecisionService.get_variation', return_value=None) as mock_decision:
-      self.assertEqual(decision_service.Decision(expected_experiment,
+      self.assertEqual(decision_service.Decision(None,
                                                  None,
-                                                 decision_service.DECISION_SOURCE_EXPERIMENT),
+                                                 decision_service.DECISION_SOURCE_ROLLOUT),
                        self.decision_service.get_variation_for_feature(feature, 'test_user'))
 
     mock_decision.assert_called_once_with(
@@ -667,7 +666,7 @@ def test_get_variation_for_feature__returns_none_for_invalid_group_id(self):
 
     with self.mock_decision_logger as mock_decision_logging:
       self.assertEqual(
-        decision_service.Decision(None, None, decision_service.DECISION_SOURCE_EXPERIMENT),
+        decision_service.Decision(None, None, decision_service.DECISION_SOURCE_ROLLOUT),
         self.decision_service.get_variation_for_feature(feature, 'test_user')
       )
     mock_decision_logging.error.assert_called_once_with(
@@ -679,13 +678,12 @@ def test_get_variation_for_feature__returns_none_for_user_in_group_experiment_no
     not targeting a feature, then None is returned. """
 
     feature = self.project_config.get_feature_from_key('test_feature_in_group')
-    expected_experiment = self.project_config.get_experiment_from_key('group_exp_2')
 
     with mock.patch('optimizely.decision_service.DecisionService.get_experiment_in_group',
                     return_value=self.project_config.get_experiment_from_key('group_exp_2')) as mock_decision:
-      self.assertEqual(decision_service.Decision(expected_experiment,
+      self.assertEqual(decision_service.Decision(None,
                                                  None,
-                                                 decision_service.DECISION_SOURCE_EXPERIMENT),
+                                                 decision_service.DECISION_SOURCE_ROLLOUT),
                        self.decision_service.get_variation_for_feature(feature, 'test_user'))
 
     mock_decision.assert_called_once_with(self.project_config.get_group('19228'), 'test_user')