use ITargetingContext & check runtime context type

Author: zhiyuanliang-ms

src/Microsoft.FeatureManagement/FeatureManager.cs

@@ -144,7 +144,7 @@ public async Task<bool> IsEnabledAsync(string feature)
         /// Checks whether a given feature is enabled.
         /// </summary>
         /// <param name="feature">The name of the feature to check.</param>
-        /// <param name="appContext">A context that provides information that can be used to evaluate whether a feature should be on or off.</param>
+        /// <param name="appContext">A context that provides information to evaluate whether a feature should be on or off.</param>
         /// <returns>True if the feature is enabled, otherwise false.</returns>
         public async Task<bool> IsEnabledAsync<TContext>(string feature, TContext appContext)
         {
@@ -170,7 +170,7 @@ public async ValueTask<bool> IsEnabledAsync(string feature, CancellationToken ca
         /// Checks whether a given feature is enabled.
         /// </summary>
         /// <param name="feature">The name of the feature to check.</param>
-        /// <param name="appContext">A context that provides information that can be used to evaluate whether a feature should be on or off.</param>
+        /// <param name="appContext">A context that provides information to evaluate whether a feature should be on or off.</param>
         /// <param name="cancellationToken">The cancellation token to cancel the operation.</param>
         /// <returns>True if the feature is enabled, otherwise false.</returns>
         public async ValueTask<bool> IsEnabledAsync<TContext>(string feature, TContext appContext, CancellationToken cancellationToken = default)
@@ -228,7 +228,7 @@ public async ValueTask<Variant> GetVariantAsync(string feature, CancellationToke
         /// <param name="context">A context that provides information to evaluate which variant will be assigned to the user.</param>
         /// <param name="cancellationToken">The cancellation token to cancel the operation.</param>
         /// <returns>A variant assigned to the user based on the feature's configured allocation.</returns>
-        public async ValueTask<Variant> GetVariantAsync<TContext>(string feature, TContext context, CancellationToken cancellationToken = default)
+        public async ValueTask<Variant> GetVariantAsync(string feature, ITargetingContext context, CancellationToken cancellationToken = default)
         {
             if (string.IsNullOrEmpty(feature))
             {
@@ -318,7 +318,7 @@ private async ValueTask<EvaluationEvent> EvaluateFeature<TContext>(string featur
 
                             if (useContext)
                             {
-                                message = $"A {nameof(ITargetingContext)} required for variant assignment was not provided.";
+                                message = $"The context of type {context.GetType().Name} does not implement {nameof(ITargetingContext)} for variant assignment.";
                             }
                             else if (TargetingContextAccessor == null)
                             {
@@ -500,7 +500,7 @@ private async ValueTask<bool> IsEnabledAsync<TContext>(FeatureDefinition feature
 
                     if (useAppContext)
                     {
-                        filter = GetFeatureFilterMetadata(featureFilterConfiguration.Name, typeof(TContext)) ??
+                        filter = GetFeatureFilterMetadata(featureFilterConfiguration.Name, appContext.GetType()) ??
                                  GetFeatureFilterMetadata(featureFilterConfiguration.Name);
                     }
                     else
@@ -542,7 +542,7 @@ private async ValueTask<bool> IsEnabledAsync<TContext>(FeatureDefinition feature
                     // IContextualFeatureFilter
                     if (useAppContext)
                     {
-                        ContextualFeatureFilterEvaluator contextualFilter = GetContextualFeatureFilter(featureFilterConfiguration.Name, typeof(TContext));
+                        ContextualFeatureFilterEvaluator contextualFilter = GetContextualFeatureFilter(featureFilterConfiguration.Name, appContext.GetType());
 
                         if (contextualFilter != null &&
                             await contextualFilter.EvaluateAsync(context, appContext).ConfigureAwait(false) == targetEvaluation)

src/Microsoft.FeatureManagement/FeatureManagerSnapshot.cs

@@ -97,7 +97,7 @@ public async ValueTask<Variant> GetVariantAsync(string feature, CancellationToke
             return variant;
         }
 
-        public async ValueTask<Variant> GetVariantAsync<TContext>(string feature, TContext context, CancellationToken cancellationToken)
+        public async ValueTask<Variant> GetVariantAsync(string feature, ITargetingContext context, CancellationToken cancellationToken)
         {
             string cacheKey = GetVariantCacheKey(feature);
 

src/Microsoft.FeatureManagement/IFeatureManager.cs

@@ -28,7 +28,7 @@ public interface IFeatureManager
         /// Checks whether a given feature is enabled.
         /// </summary>
         /// <param name="feature">The name of the feature to check.</param>
-        /// <param name="context">A context that provides information that can be used to evaluate whether a feature should be on or off.</param>
+        /// <param name="context">A context that provides information to evaluate whether a feature should be on or off.</param>
         /// <returns>True if the feature is enabled, otherwise false.</returns>
         Task<bool> IsEnabledAsync<TContext>(string feature, TContext context);
     }

src/Microsoft.FeatureManagement/IVariantFeatureManager.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 //
+using Microsoft.FeatureManagement.FeatureFilters;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
@@ -31,7 +32,7 @@ public interface IVariantFeatureManager
         /// Checks whether a given feature is enabled.
         /// </summary>
         /// <param name="feature">The name of the feature to check.</param>
-        /// <param name="context">A context that provides information that can be used to evaluate whether a feature should be on or off.</param>
+        /// <param name="context">A context that provides information to evaluate whether a feature should be on or off.</param>
         /// <param name="cancellationToken">The cancellation token to cancel the operation.</param>
         /// <returns>True if the feature is enabled, otherwise false.</returns>
         ValueTask<bool> IsEnabledAsync<TContext>(string feature, TContext context, CancellationToken cancellationToken = default);
@@ -51,6 +52,6 @@ public interface IVariantFeatureManager
         /// <param name="context">A context that provides information to evaluate which variant will be assigned to the user.</param>
         /// <param name="cancellationToken">The cancellation token to cancel the operation.</param>
         /// <returns>A variant assigned to the user based on the feature's configured allocation.</returns>
-        ValueTask<Variant> GetVariantAsync<TContext>(string feature, TContext context, CancellationToken cancellationToken = default);
+        ValueTask<Variant> GetVariantAsync(string feature, ITargetingContext context, CancellationToken cancellationToken = default);
     }
 }

tests/Tests.FeatureManagement/AppContext.cs

@@ -1,10 +1,17 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 //
+using Microsoft.FeatureManagement.FeatureFilters;
+using System.Collections.Generic;
+
 namespace Tests.FeatureManagement
 {
-    class AppContext : IAccountContext
+    class AppContext : IAccountContext, ITargetingContext
     {
         public string AccountId { get; set; }
+
+        public string UserId { get; set; }
+
+        public IEnumerable<string> Groups { get; set; }
     }
 }

tests/Tests.FeatureManagement/ContextualTestFilter.cs

@@ -7,11 +7,11 @@
 
 namespace Tests.FeatureManagement
 {
-    class ContextualTestFilter : IContextualFeatureFilter<IAccountContext>
+    class ContextualTestFilter : IContextualFeatureFilter<AppContext>
     {
-        public Func<FeatureFilterEvaluationContext, IAccountContext, bool> ContextualCallback { get; set; }
+        public Func<FeatureFilterEvaluationContext, AppContext, bool> ContextualCallback { get; set; }
 
-        public Task<bool> EvaluateAsync(FeatureFilterEvaluationContext context, IAccountContext accountContext)
+        public Task<bool> EvaluateAsync(FeatureFilterEvaluationContext context, AppContext accountContext)
         {
             return Task.FromResult(ContextualCallback?.Invoke(context, accountContext) ?? false);
         }

tests/Tests.FeatureManagement/FeatureManagementTest.cs

@@ -1670,7 +1670,7 @@ public async Task VariantFeatureFlagWithContextualFeatureFilter()
 
             IVariantFeatureManager featureManager = serviceProvider.GetRequiredService<IVariantFeatureManager>();
 
-            AppContext context = new AppContext();
+            var context = new AppContext();
 
             context.AccountId = "NotEnabledAccount";