Adds TargetingContext to EvaluationEvent & Emits TargetingId in the App Insights Publisher (#347)

* Adds TargetingId to EvaluationEvent

* Adjusts EvaluationEvent to use TargetingContext instead of ITargetingContext

Author: rossgrambo

src/Microsoft.FeatureManagement.Telemetry.ApplicationInsights/ApplicationInsightsTelemetryPublisher.cs

@@ -42,6 +42,11 @@ public ValueTask PublishEvent(EvaluationEvent evaluationEvent, CancellationToken
                 { "Enabled", evaluationEvent.Enabled.ToString() }
             };
 
+            if (evaluationEvent.TargetingContext != null)
+            {
+                properties["TargetingId"] = evaluationEvent.TargetingContext.UserId;
+            }
+
             if (evaluationEvent.VariantAssignmentReason != VariantAssignmentReason.None)
             {
                 properties["Variant"] = evaluationEvent.Variant?.Name;

src/Microsoft.FeatureManagement/FeatureManager.cs

@@ -263,6 +263,21 @@ private async Task<EvaluationEvent> EvaluateFeature<TContext>(string feature, TC
                 FeatureDefinition = await GetFeatureDefinition(feature).ConfigureAwait(false)
             };
 
+            //
+            // Determine Targeting Context
+            TargetingContext targetingContext;
+
+            if (useContext)
+            {
+                targetingContext = context as TargetingContext;
+            }
+            else
+            {
+                targetingContext = await ResolveTargetingContextAsync(cancellationToken).ConfigureAwait(false);
+            }
+
+            evaluationEvent.TargetingContext = targetingContext;
+
             if (evaluationEvent.FeatureDefinition != null)
             {
                 //
@@ -296,17 +311,6 @@ private async Task<EvaluationEvent> EvaluateFeature<TContext>(string feature, TC
                     }
                     else
                     {
-                        TargetingContext targetingContext;
-
-                        if (useContext)
-                        {
-                            targetingContext = context as TargetingContext;
-                        }
-                        else
-                        {
-                            targetingContext = await ResolveTargetingContextAsync(cancellationToken).ConfigureAwait(false);
-                        }
-
                         if (targetingContext != null && evaluationEvent.FeatureDefinition.Allocation != null)
                         {
                             variantDefinition = await AssignVariantAsync(evaluationEvent, targetingContext, cancellationToken).ConfigureAwait(false);

src/Microsoft.FeatureManagement/Telemetry/EvaluationEvent.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 //
+using Microsoft.FeatureManagement.FeatureFilters;
+
 namespace Microsoft.FeatureManagement.Telemetry
 {
     /// <summary>
@@ -13,6 +15,11 @@ public class EvaluationEvent
         /// </summary>
         public FeatureDefinition FeatureDefinition { get; set; }
 
+        /// <summary>
+        /// The targeting context used to evaluate the feature.
+        /// </summary>
+        public TargetingContext TargetingContext { get; set; }
+
         /// <summary>
         /// The enabled state of the feature after evaluation.
         /// </summary>

tests/Tests.FeatureManagement/FeatureManagement.cs

@@ -1087,6 +1087,7 @@ public async Task TelemetryPublishing()
             variantResult = await featureManager.GetVariantAsync(Features.VariantFeaturePercentileOn, cancellationToken);
             Assert.Equal("Big", variantResult.Name);
             Assert.Equal("Big", testPublisher.evaluationEventCache.Variant.Name);
+            Assert.Equal("Marsha", testPublisher.evaluationEventCache.TargetingContext.UserId);
             Assert.Equal(VariantAssignmentReason.Percentile, testPublisher.evaluationEventCache.VariantAssignmentReason);
 
             variantResult = await featureManager.GetVariantAsync(Features.VariantFeaturePercentileOff, cancellationToken);