UI for Feature Flags (#7052)

Author: Scott Bommarito

src/NuGetGallery.Core/Features/FeatureFlagFileStorageService.cs

@@ -49,47 +49,27 @@ public FeatureFlagFileStorageService(
         public async Task<FeatureFlags> GetAsync()
         {
             using (var stream = await _storage.GetFileAsync(CoreConstants.Folders.ContentFolderName, CoreConstants.FeatureFlagsFileName))
-            using (var streamReader = new StreamReader(stream))
-            using (var reader = new JsonTextReader(streamReader))
             {
-                return Serializer.Deserialize<FeatureFlags>(reader);
+                return ReadFeatureFlagsFromStream(stream);
             }
         }
 
         public async Task<FeatureFlagReference> GetReferenceAsync()
         {
             var reference = await _storage.GetFileReferenceAsync(CoreConstants.Folders.ContentFolderName, CoreConstants.FeatureFlagsFileName);
 
-            string json;
-            using (var stream = reference.OpenRead())
-            using (var streamReader = new StreamReader(stream))
-            {
-                json = await streamReader.ReadToEndAsync();
-            }
-
             return new FeatureFlagReference(
-                PrettifyJson(json),
+                ReadFeatureFlagsFromStream(reference.OpenRead()),
                 reference.ContentId);
         }
 
-        public async Task<FeatureFlagSaveResult> TrySaveAsync(string flagsJson, string contentId)
+        private FeatureFlags ReadFeatureFlagsFromStream(Stream stream)
         {
-            // Ensure the feature flags are valid before saving them.
-            FeatureFlags flags;
-            try
-            {
-                using (var reader = new StringReader(flagsJson))
-                using (var jsonReader = new JsonTextReader(reader))
-                {
-                    flags = Serializer.Deserialize<FeatureFlags>(jsonReader);
-                }
-            }
-            catch (JsonException e)
+            using (var streamReader = new StreamReader(stream))
+            using (var reader = new JsonTextReader(streamReader))
             {
-                return FeatureFlagSaveResult.Invalid(e.Message);
+                return Serializer.Deserialize<FeatureFlags>(reader);
             }
-
-            return await TrySaveAsync(flags, contentId);
         }
 
         public async Task RemoveUserAsync(User user)
@@ -122,7 +102,7 @@ public async Task RemoveUserAsync(User user)
                            f => RemoveUser(f.Value, user)));
 
                 var saveResult = await TrySaveAsync(result, reference.ContentId);
-                if (saveResult.Type == FeatureFlagSaveResultType.Ok)
+                if (saveResult == FeatureFlagSaveResult.Ok)
                 {
                     return;
                 }
@@ -137,7 +117,7 @@ public async Task RemoveUserAsync(User user)
             throw new InvalidOperationException($"Unable to remove user from feature flags after {MaxRemoveUserAttempts} attempts");
         }
 
-        private async Task<FeatureFlagSaveResult> TrySaveAsync(FeatureFlags flags, string contentId)
+        public async Task<FeatureFlagSaveResult> TrySaveAsync(FeatureFlags flags, string contentId)
         {
             var accessCondition = AccessConditionWrapper.GenerateIfMatchCondition(contentId);
 
@@ -170,10 +150,5 @@ private Flight RemoveUser(Flight flight, User user)
                 flight.Accounts.Where(a => !a.Equals(user.Username, StringComparison.OrdinalIgnoreCase)).ToList(),
                 flight.Domains);
         }
-
-        private string PrettifyJson(string json)
-        {
-            return JToken.Parse(json).ToString(Formatting.Indented);
-        }
     }
 }

src/NuGetGallery.Core/Features/FeatureFlagReference.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using NuGet.Services.FeatureFlags;
 
 namespace NuGetGallery.Features
 {
@@ -10,26 +11,21 @@ namespace NuGetGallery.Features
     /// </summary>
     public class FeatureFlagReference
     {
-        public FeatureFlagReference(string flagsJson, string contentId)
+        public FeatureFlagReference(FeatureFlags flags, string contentId)
         {
-            if (string.IsNullOrEmpty(flagsJson))
-            {
-                throw new ArgumentException(nameof(flagsJson));
-            }
-
             if (string.IsNullOrEmpty(contentId))
             {
                 throw new ArgumentException(nameof(contentId));
             }
 
-            FlagsJson = flagsJson;
+            Flags = flags ?? throw new ArgumentException(nameof(flags));
             ContentId = contentId;
         }
 
         /// <summary>
         /// The feature flag's content, serialized as JSON.
         /// </summary>
-        public string FlagsJson { get; }
+        public FeatureFlags Flags { get; }
 
         /// <summary>
         /// The feature flag's ETag.

src/NuGetGallery.Core/Features/FeatureFlagSaveResult.cs

@@ -6,30 +6,16 @@ namespace NuGetGallery.Features
     /// <summary>
     /// The result of calling <see cref="FeatureFlagFileStorageService.TrySaveAsync(string, string)"/>.
     /// </summary>
-    public class FeatureFlagSaveResult
+    public enum FeatureFlagSaveResult
     {
-        private FeatureFlagSaveResult(FeatureFlagSaveResultType type, string message = null)
-        {
-            Type = type;
-            Message = message ?? string.Empty;
-        }
-
-        public static readonly FeatureFlagSaveResult Ok = new FeatureFlagSaveResult(FeatureFlagSaveResultType.Ok);
-        public static readonly FeatureFlagSaveResult Conflict = new FeatureFlagSaveResult(FeatureFlagSaveResultType.Conflict);
-
-        public static FeatureFlagSaveResult Invalid(string message)
-        {
-            return new FeatureFlagSaveResult(FeatureFlagSaveResultType.Invalid, message);
-        }
-
         /// <summary>
-        /// An error code explaining whether the save operation succeeded.
+        /// The flags were saved successfully.
         /// </summary>
-        public FeatureFlagSaveResultType Type { get; }
+        Ok,
 
         /// <summary>
-        /// A non-null string explaining the result. Empty unless <see cref="Type"/> is <see cref="FeatureFlagSaveResultType.Invalid"/>.
+        /// The flags were modified by someone else.
         /// </summary>
-        public string Message { get; }
+        Conflict,
     }
 }

src/NuGetGallery.Core/Features/FeatureFlagSaveResultType.cs

@@ -20,10 +20,10 @@ public interface IEditableFeatureFlagStorageService : IFeatureFlagStorageService
         /// <summary>
         /// Try to update the feature flags.
         /// </summary>
-        /// <param name="flags">The feature flags serialized in JSON.</param>
+        /// <param name="flags">The feature flags.</param>
         /// <param name="contentId">The feature flag's ETag.</param>
         /// <returns>The result of the save operation.</returns>
-        Task<FeatureFlagSaveResult> TrySaveAsync(string flags, string contentId);
+        Task<FeatureFlagSaveResult> TrySaveAsync(FeatureFlags flags, string contentId);
 
         /// <summary>
         /// Remove the user from the feature flags if needed. This may throw on failure.

src/NuGetGallery.Core/Features/IEditableFeatureFlagStorageService.cs

@@ -136,7 +136,6 @@
     <Compile Include="Features\FeatureFlagClientExtensions.cs" />
     <Compile Include="Features\FeatureFlagReference.cs" />
     <Compile Include="Features\FeatureFlagSaveResult.cs" />
-    <Compile Include="Features\FeatureFlagSaveResultType.cs" />
     <Compile Include="Features\IEditableFeatureFlagStorageService.cs" />
     <Compile Include="ICloudStorageStatusDependency.cs" />
     <Compile Include="Infrastructure\AzureEntityList.cs" />