Add support for dynamic features.

Microsoft.FeatureManagement.sln

@@ -19,6 +19,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ConsoleApp", "examples\Cons
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "TargetingConsoleApp", "examples\TargetingConsoleApp\TargetingConsoleApp.csproj", "{6558C21E-CF20-4278-AA08-EB9D1DF29D66}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CustomAssignmentConsoleApp", "examples\CustomAssignmentConsoleApp\CustomAssignmentConsoleApp.csproj", "{06C10E31-4C33-4567-85DB-00056A2BB511}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -49,6 +51,10 @@ Global
 		{6558C21E-CF20-4278-AA08-EB9D1DF29D66}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{6558C21E-CF20-4278-AA08-EB9D1DF29D66}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{6558C21E-CF20-4278-AA08-EB9D1DF29D66}.Release|Any CPU.Build.0 = Release|Any CPU
+		{06C10E31-4C33-4567-85DB-00056A2BB511}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{06C10E31-4C33-4567-85DB-00056A2BB511}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{06C10E31-4C33-4567-85DB-00056A2BB511}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{06C10E31-4C33-4567-85DB-00056A2BB511}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -58,6 +64,7 @@ Global
 		{FDBB27BA-C5BA-48A7-BA9B-63159943EA9F} = {8ED6FFEE-4037-49A2-9709-BC519C104A90}
 		{E50FB931-7A42-440E-AC47-B8DFE5E15394} = {FB5C34DF-695C-4DF9-8AED-B3EA2516EA72}
 		{6558C21E-CF20-4278-AA08-EB9D1DF29D66} = {FB5C34DF-695C-4DF9-8AED-B3EA2516EA72}
+		{06C10E31-4C33-4567-85DB-00056A2BB511} = {FB5C34DF-695C-4DF9-8AED-B3EA2516EA72}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {84DA6C54-F140-4518-A1B4-E4CF42117FBD}

examples/CustomAssignmentConsoleApp/CustomAssignmentConsoleApp.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+    <RootNamespace>Consoto.Banking.AccountService</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="5.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="5.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Microsoft.FeatureManagement\Microsoft.FeatureManagement.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Update="appsettings.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>

examples/CustomAssignmentConsoleApp/DailyDiscountOptions.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+namespace Consoto.Banking.HelpDesk
+{
+    class DailyDiscountOptions
+    {
+        public string ProductName { get; set; }
+
+        public int Discount { get; set; }
+    }
+}

examples/CustomAssignmentConsoleApp/Program.cs

@@ -0,0 +1,49 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+using Consoto.Banking.AccountService;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.FeatureManagement;
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Consoto.Banking.HelpDesk
+{
+    class Program
+    {
+        public static async Task Main(string[] args)
+        {
+            //
+            // Setup configuration
+            IConfiguration configuration = new ConfigurationBuilder()
+                .AddJsonFile("appsettings.json", false, true)
+                .Build();
+
+            //
+            // Setup application services + feature management
+            IServiceCollection services = new ServiceCollection();
+
+            services.AddSingleton(typeof(IFeatureVariantAssignerMetadata), typeof(RecurringAssigner));
+
+            services.AddSingleton(configuration)
+                    .AddFeatureManagement()
+                    .AddFeatureVariantAssigner<RecurringAssigner>();
+
+            //
+            // Get the feature manager from application services
+            using (ServiceProvider serviceProvider = services.BuildServiceProvider())
+            {
+                IFeatureVariantManager variantManager = serviceProvider.GetRequiredService<IFeatureVariantManager>();
+
+                DailyDiscountOptions discountOptions = await variantManager
+                    .GetVariantAsync<DailyDiscountOptions>("DailyDiscount", CancellationToken.None);
+
+                //
+                // Output results
+                Console.WriteLine($"Today there is a {discountOptions.Discount}% discount on {discountOptions.ProductName}!");
+            }
+        }
+    }
+}

examples/CustomAssignmentConsoleApp/RecurringAssigner.cs

@@ -0,0 +1,41 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+using Microsoft.Extensions.Configuration;
+using Microsoft.FeatureManagement;
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Consoto.Banking.AccountService
+{
+    [AssignerAlias("Recurring")]
+    class RecurringAssigner : IFeatureVariantAssigner
+    {
+        public ValueTask<FeatureVariant> AssignVariantAsync(FeatureVariantAssignmentContext variantAssignmentContext, CancellationToken _)
+        {
+            FeatureDefinition featureDefinition = variantAssignmentContext.FeatureDefinition;
+
+            FeatureVariant chosenVariant = null;
+
+            string currentDay = DateTimeOffset.UtcNow.DayOfWeek.ToString();
+
+            foreach (var variant in featureDefinition.Variants)
+            {
+                RecurringAssignmentParameters p = variant.AssignmentParameters.Get<RecurringAssignmentParameters>() ??
+                                                    new RecurringAssignmentParameters();
+
+                if (p.Days != null &&
+                    p.Days.Any(d => d.Equals(currentDay, StringComparison.OrdinalIgnoreCase)))
+                {
+                    chosenVariant = variant;
+
+                    break;
+                }
+            }
+
+            return new ValueTask<FeatureVariant>(chosenVariant);
+        }
+    }
+}

examples/CustomAssignmentConsoleApp/RecurringAssignmentParameters.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+using System.Collections.Generic;
+
+namespace Consoto.Banking.AccountService
+{
+    class RecurringAssignmentParameters
+    {
+        public List<string> Days { get; set; }
+    }
+}

examples/CustomAssignmentConsoleApp/appsettings.json

@@ -0,0 +1,33 @@
+{
+  "FeatureManagement": {
+    "DailyDiscount": {
+      "Assigner": "Recurring",
+      "Variants": [
+        {
+          "Default": true,
+          "Name": "Default",
+          "ConfigurationReference": "DailyDiscount:Default"
+        },
+        {
+          "Name": "Special",
+          "ConfigurationReference": "DailyDiscount:Special",
+          "AssignmentParameters": {
+            "Days": [
+              "Tuesday"
+            ]
+          }
+        }
+      ]
+    }
+  },
+  "DailyDiscount": {
+    "Default": {
+      "Discount": 20,
+      "ProductName": "Bananas"
+    },
+    "Special": {
+      "Discount": 30,
+      "ProductName": "Fish"
+    }
+  }
+}

examples/FeatureFlagDemo/Controllers/HomeController.cs

@@ -31,9 +31,9 @@ public async Task<IActionResult> About(CancellationToken cancellationToken)
         {
             ViewData["Message"] = "Your application description page.";
 
-            if (await _featureManager.IsEnabledAsync(nameof(MyFeatureFlags.CustomViewData), cancellationToken))
+            if (await _featureManager.IsEnabledAsync(MyFeatureFlags.CustomViewData, cancellationToken))
             {
-                ViewData["Message"] = $"This is FANCY CONTENT you can see only if '{nameof(MyFeatureFlags.CustomViewData)}' is enabled.";
+                ViewData["Message"] = $"This is FANCY CONTENT you can see only if '{MyFeatureFlags.CustomViewData}' is enabled.";
             };
 
             return View();

examples/FeatureFlagDemo/DiscountBannerOptions.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+namespace FeatureFlagDemo
+{
+    public class DiscountBannerOptions
+    {
+        public int Size { get; set; }
+
+        public string Color { get; set; }
+
+        public string Background { get; set; }
+    }
+}

examples/FeatureFlagDemo/MyFeatureFlags.cs

@@ -3,14 +3,12 @@
 //
 namespace FeatureFlagDemo
 {
-    //
-    // Define feature flags in an enum
-    public enum MyFeatureFlags
+    static class MyFeatureFlags
     {
-        Home,
-        Beta,
-        CustomViewData,
-        ContentEnhancement,
-        EnhancedPipeline
+        public const string Home = "Home";
+        public const string Beta = "Beta";
+        public const string CustomViewData = "CustomViewData";
+        public const string ContentEnhancement = "ContentEnhancement";
+        public const string EnhancedPipeline = "EnhancedPipeline";
     }
 }

examples/FeatureFlagDemo/Startup.cs

@@ -59,6 +59,7 @@ public void ConfigureServices(IServiceCollection services)
                     .AddFeatureFilter<TimeWindowFilter>()
                     .AddFeatureFilter<PercentageFilter>()
                     .AddFeatureFilter<TargetingFilter>()
+                    .AddFeatureVariantAssigner<TargetingFeatureVariantAssigner>()
                     .UseDisabledFeaturesHandler(new FeatureNotEnabledDisabledHandler());
 
             services.AddMvc(o =>

examples/FeatureFlagDemo/Views/Shared/_Layout.cshtml

@@ -1,4 +1,10 @@
-<!DOCTYPE html>
+@using Microsoft.FeatureManagement
+@inject IFeatureVariantManager variantManager;
+@{
+    DiscountBannerOptions opts = await variantManager.GetVariantAsync<DiscountBannerOptions>("DiscountBanner", Context.RequestAborted);
+}
+
+<!DOCTYPE html>
 <html>
 <head>
     <meta charset="utf-8" />
@@ -15,6 +21,14 @@
               asp-fallback-test-class="sr-only" asp-fallback-test-property="position" asp-fallback-test-value="absolute" />
         <link rel="stylesheet" href="~/css/site.min.css" asp-append-version="true" />
     </environment>
+    <style type="text/css">
+        .notification-banner {
+            text-align: center;
+            color: @opts.Color;
+            font-size: @(opts.Size)px;
+            background: @(opts.Background)
+        }
+    </style>
 </head>
 <body>
     <nav class="navbar navbar-inverse navbar-fixed-top">
@@ -42,7 +56,9 @@
     </nav>
 
     <partial name="_CookieConsentPartial" />
-
+    <div class="notification-banner">
+        New Sale, 50% Off !
+    </div>
     <div class="container body-content">
         @RenderBody()
     </div>

examples/FeatureFlagDemo/appsettings.json

@@ -66,6 +66,51 @@
           }
         }
       ]
+    },
+    "DiscountBanner": {
+      "Assigner": "Targeting",
+      "Variants": [
+        {
+          "Default": true,
+          "Name": "Big",
+          "ConfigurationReference": "DiscountBanner:Big"
+        },
+        {
+          "Name": "Small",
+          "ConfigurationReference": "DiscountBanner:Small",
+          "AssignmentParameters": {
+            "Audience": {
+              "Users": [
+                "Jeff",
+                "Alicia"
+              ],
+              "Groups": [
+                {
+                  "Name": "Ring0",
+                  "RolloutPercentage": 80
+                },
+                {
+                  "Name": "Ring1",
+                  "RolloutPercentage": 50
+                }
+              ],
+              "DefaultRolloutPercentage": 20
+            }
+          }
+        }
+      ]
+    }
+  },
+  "DiscountBanner": {
+    "Small": {
+      "Size": 24,
+      "Color": "#c9f568",
+      "Background": "#f35220"
+    },
+    "Big": {
+      "Size": 48,
+      "Color": "#007cb3",
+      "Background": "#ffbb02"
     }
   }
 }

examples/TargetingConsoleApp/CartOptions.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+namespace Consoto.Banking.HelpDesk
+{
+    class CartOptions
+    {
+        public int Size { get; set; }
+
+        public string Color { get; set; }
+    }
+}