feat(DecisionListener): Adds feature decision listener. (#164)

Author: rashidsp

src/Optimizely/DecisionService/DecisionService.php

@@ -197,7 +197,7 @@ public function getVariationForFeature(FeatureFlag $featureFlag, $userId, $userA
             "User '{$userId}' is not bucketed into rollout for feature flag '{$featureFlag->getKey()}'."
         );
 
-        return null;
+        return new FeatureDecision(null, null, FeatureDecision::DECISION_SOURCE_ROLLOUT);
     }
 
     /**

src/Optimizely/DecisionService/FeatureDecision.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * Copyright 2017, Optimizely Inc and Contributors
+ * Copyright 2017, 2019 Optimizely Inc and Contributors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,8 +18,8 @@
 
 class FeatureDecision
 {
-    const DECISION_SOURCE_EXPERIMENT = 'experiment';
-    const DECISION_SOURCE_ROLLOUT = 'rollout';
+    const DECISION_SOURCE_EXPERIMENT = 'EXPERIMENT';
+    const DECISION_SOURCE_ROLLOUT = 'ROLLOUT';
 
     /**
      * The experiment in this decision.

src/Optimizely/Enums/DecisionInfoTypes.php

@@ -0,0 +1,25 @@
+<?php
+/**
+ * Copyright 2019, Optimizely
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Optimizely\Enums;
+
+class DecisionInfoTypes
+{
+    const EXPERIMENT = "experiment";
+    const FEATURE = "feature";
+    const FEATURE_VARIABLE = "feature_variable";
+}

src/Optimizely/Notification/NotificationType.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * Copyright 2017, Optimizely Inc and Contributors
+ * Copyright 2017, 2019, Optimizely Inc and Contributors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@ class NotificationType
 {
     // format is EVENT: list of parameters to callback.
     const ACTIVATE = "ACTIVATE:experiment, user_id, attributes, variation, event";
+    const DECISION = "DECISION:type, user_id, attributes, decision_info";
     const TRACK = "TRACK:event_key, user_id, attributes, event_tags, event";
 
     public static function isNotificationTypeValid($notification_type)

src/Optimizely/Optimizely.php

@@ -27,6 +27,7 @@
 use Optimizely\DecisionService\FeatureDecision;
 use Optimizely\Entity\Experiment;
 use Optimizely\Entity\FeatureVariable;
+use Optimizely\Enums\DecisionInfoTypes;
 use Optimizely\ErrorHandler\ErrorHandlerInterface;
 use Optimizely\ErrorHandler\NoOpErrorHandler;
 use Optimizely\Event\Builder\EventBuilder;
@@ -500,24 +501,41 @@ public function isFeatureEnabled($featureFlagKey, $userId, $attributes = null)
             return false;
         }
 
+        $featureEnabled = false;
         $decision = $this->_decisionService->getVariationForFeature($featureFlag, $userId, $attributes);
-        if (!$decision) {
-            $this->_logger->log(Logger::INFO, "Feature Flag '{$featureFlagKey}' is not enabled for user '{$userId}'.");
-            return false;
-        }
-
-        $experiment = $decision->getExperiment();
         $variation = $decision->getVariation();
-
-        if ($decision->getSource() == FeatureDecision::DECISION_SOURCE_EXPERIMENT) {
-            $this->sendImpressionEvent($experiment->getKey(), $variation->getKey(), $userId, $attributes);
-        } else {
-            $this->_logger->log(Logger::INFO, "The user '{$userId}' is not being experimented on Feature Flag '{$featureFlagKey}'.");
+        if ($variation) {
+            $experiment = $decision->getExperiment();
+            $featureEnabled = $variation->getFeatureEnabled();
+            if ($decision->getSource() == FeatureDecision::DECISION_SOURCE_EXPERIMENT) {
+                $experimentKey = $experiment->getKey();
+                $variationKey = $variation->getKey();
+                $this->sendImpressionEvent($experimentKey, $variationKey, $userId, $attributes);
+            } else {
+                $this->_logger->log(Logger::INFO, "The user '{$userId}' is not being experimented on Feature Flag '{$featureFlagKey}'.");
+            }
         }
 
-        if ($variation->getFeatureEnabled()) {
+        $attributes = is_null($attributes) ? [] : $attributes;
+        $this->notificationCenter->sendNotifications(
+            NotificationType::DECISION,
+            array(
+                DecisionInfoTypes::FEATURE,
+                $userId,
+                $attributes,
+                (object) array(
+                    'featureKey'=>$featureFlagKey,
+                    'featureEnabled'=> $featureEnabled,
+                    'source'=> $decision->getSource(),
+                    'sourceExperimentKey'=> isset($experimentKey) ? $experimentKey : null,
+                    'sourceVariationKey'=> isset($variationKey) ? $variationKey : null
+                )
+            )
+        );
+
+        if ($featureEnabled == true) {
             $this->_logger->log(Logger::INFO, "Feature Flag '{$featureFlagKey}' is enabled for user '{$userId}'.");
-            return true;
+            return $featureEnabled;
         }
 
         $this->_logger->log(Logger::INFO, "Feature Flag '{$featureFlagKey}' is not enabled for user '{$userId}'.");
@@ -611,8 +629,9 @@ public function getFeatureVariableValueForType(
 
         $decision = $this->_decisionService->getVariationForFeature($featureFlag, $userId, $attributes);
         $variableValue = $variable->getDefaultValue();
+        $variation = $decision->getVariation();
 
-        if (!$decision) {
+        if ($variation === null) {
             $this->_logger->log(
                 Logger::INFO,
                 "User '{$userId}'is not in any variation, ".

tests/DecisionServiceTests/DecisionServiceTest.php

@@ -909,7 +909,16 @@ public function testGetVariationForFeatureWhenTheUserIsNeitherBucketedIntoFeatur
                 "User 'user_1' is not bucketed into rollout for feature flag 'string_single_variable_feature'."
             );
 
-        $this->assertNull($decisionServiceMock->getVariationForFeature($featureFlag, 'user_1', []));
+        // mock getVariationForFeature to return rolloutDecision
+        $expectedDecision = new FeatureDecision(
+            null,
+            null,
+            FeatureDecision::DECISION_SOURCE_ROLLOUT
+        );
+        $this->assertEquals(
+            $decisionServiceMock->getVariationForFeature($featureFlag, 'user_1', []),
+            $expectedDecision
+        );
     }
 
     // should return null