in progress, add new classes for variants and define methods in featuremanager

Author: amerjusupovic

src/Microsoft.FeatureManagement/Allocation.cs

@@ -0,0 +1,29 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+using Microsoft.FeatureManagement.FeatureFilters;
+using System.Collections.Generic;
+
+namespace Microsoft.FeatureManagement
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public class Allocation
+    {
+        /// <summary>
+        /// Describes a mapping of user id to variant.
+        /// </summary>
+        public List<string> Users { get; set; }
+
+        /// <summary>
+        /// Describes a mapping of group names to variants.
+        /// </summary>
+        public List<GroupRollout> Groups { get; set; }
+
+        /// <summary>
+        /// Allocate a percentage of the user base to variants.
+        /// </summary>
+        public double Percentile { get; set; }
+    }
+}

src/Microsoft.FeatureManagement/FeatureDefinition.cs

@@ -25,5 +25,20 @@ public class FeatureDefinition
         /// The default value is <see cref="RequirementType.Any"/>.
         /// </summary>
         public RequirementType RequirementType { get; set; } = RequirementType.Any;
+
+        /// <summary>
+        /// kill switch
+        /// </summary>
+        public Status Status { get; set; } = Status.Conditional;
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public Allocation Allocation { get; set; };
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public List<FeatureVariant> Variants { get; set; }
     }
 }

src/Microsoft.FeatureManagement/FeatureManager.cs

@@ -16,7 +16,7 @@ namespace Microsoft.FeatureManagement
     /// <summary>
     /// Used to evaluate whether a feature is enabled or disabled.
     /// </summary>
-    class FeatureManager : IFeatureManager, IDisposable
+    class FeatureManager : IFeatureManager, IDisposable, IVariantFeatureManager
     {
         private readonly TimeSpan ParametersCacheSlidingExpiration = TimeSpan.FromMinutes(5);
         private readonly TimeSpan ParametersCacheAbsoluteExpirationRelativeToNow = TimeSpan.FromDays(1);
@@ -141,6 +141,13 @@ private async Task<bool> IsEnabledAsync<TContext>(string feature, TContext appCo
                             continue;
                         }
 
+                        //
+                        // Handle On filters for variants
+                        if (string.Equals(featureFilterConfiguration.Name, "On", StringComparison.OrdinalIgnoreCase))
+                        {
+                               // TODO
+                        }
+
                         IFeatureFilterMetadata filter = GetFeatureFilterMetadata(featureFilterConfiguration.Name);
 
                         if (filter == null)
@@ -217,6 +224,16 @@ await contextualFilter.EvaluateAsync(context, appContext).ConfigureAwait(false)
             return enabled;
         }
 
+        public ValueTask<Variant> GetVariantAsync(string feature)
+        {
+            throw new NotImplementedException();
+        }
+
+        public ValueTask<Variant> GetVariantAsync<TContext>(string feature, TContext context)
+        {
+            throw new NotImplementedException();
+        }
+
         private void BindSettings(IFeatureFilterMetadata filter, FeatureFilterEvaluationContext context, int filterIndex)
         {
             IFilterParametersBinder binder = filter as IFilterParametersBinder;

src/Microsoft.FeatureManagement/FeatureVariant.cs

@@ -0,0 +1,32 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+
+namespace Microsoft.FeatureManagement
+{
+    /// <summary>
+    /// A variant of a feature.
+    /// </summary>
+    public class FeatureVariant
+    {
+        /// <summary>
+        /// The name of the variant.
+        /// </summary>
+        public string Name { get; set; }
+
+        /// <summary>
+        /// The value of the configuration for this variant of the feature.
+        /// </summary>
+        public string ConfigurationValue { get; set; }
+
+        /// <summary>
+        /// A reference pointing to the configuration for this variant of the feature.
+        /// </summary>
+        public string ConfigurationReference { get; set; }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public StatusOverride StatusOverride { get; set; }
+    }
+}

src/Microsoft.FeatureManagement/IFeatureManager.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license.
 //
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Microsoft.FeatureManagement
@@ -21,15 +22,17 @@ public interface IFeatureManager
         /// Checks whether a given feature is enabled.
         /// </summary>
         /// <param name="feature">The name of the feature to check.</param>
+        /// <param name="cancellationToken">The cancellation token to cancel the operation.</param>
         /// <returns>True if the feature is enabled, otherwise false.</returns>
-        Task<bool> IsEnabledAsync(string feature);
+        Task<bool> IsEnabledAsync(string feature, CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Checks whether a given feature is enabled.
         /// </summary>
         /// <param name="feature">The name of the feature to check.</param>
         /// <param name="context">A context providing information that can be used 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>
-        Task<bool> IsEnabledAsync<TContext>(string feature, TContext context);
+        Task<bool> IsEnabledAsync<TContext>(string feature, TContext context, CancellationToken cancellationToken = default);
     }
 }

src/Microsoft.FeatureManagement/IVariantFeatureManager.cs

@@ -0,0 +1,45 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+using System.Threading.Tasks;
+using System.Threading;
+
+namespace Microsoft.FeatureManagement
+{
+    public interface IVariantFeatureManager
+    {
+        /// <summary>
+        /// Checks whether a given feature is enabled.
+        /// </summary>
+        /// <param name="feature">The name of the feature to check.</param>
+        /// <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        /// <returns>True if the feature is enabled, otherwise false.</returns>
+        Task<bool> IsEnabledAsync(string feature, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Checks whether a given feature is enabled.
+        /// </summary>
+        /// <param name="feature">The name of the feature to check.</param>
+        /// <param name="context">A context providing information that can be used 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>
+        Task<bool> IsEnabledAsync<TContext>(string feature, TContext context, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Gets the assigned variant for a specfic feature.
+        /// </summary>
+        /// <param name="feature">The name of the feature from which the variant will be assigned.</param>
+        /// <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        /// <returns>A variant assigned to the user based on the feature's allocation logic.</returns>
+        ValueTask<Variant> GetVariantAsync(string feature, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Gets the assigned variant for a specfic feature.
+        /// </summary>
+        /// <param name="feature">The name of the feature from which the variant will be assigned.</param>
+        /// <param name="context">A context providing information that can be used to evaluate which variant the user will be assigned.</param>
+        /// <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        /// <returns>A variant assigned to the user based on the feature's allocation logic.</returns>
+        ValueTask<Variant> GetVariantAsync<TContext>(string feature, TContext context, CancellationToken cancellationToken);
+    }
+}

src/Microsoft.FeatureManagement/Status.cs

@@ -0,0 +1,11 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+namespace Microsoft.FeatureManagement
+{
+    public enum Status
+    {
+        Conditional,
+        Disabled
+    }
+}

src/Microsoft.FeatureManagement/StatusOverride.cs

@@ -0,0 +1,11 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+namespace Microsoft.FeatureManagement
+{
+    public enum StatusOverride
+    {
+        Enabled,
+        Disabled
+    }
+}

src/Microsoft.FeatureManagement/Variant.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+using Microsoft.Extensions.Configuration;
+
+namespace Microsoft.FeatureManagement
+{
+    public class Variant
+    {
+        public string Name { get; set; }
+
+        public IConfiguration Configuration { get; set; }
+    }
+}