Feat: Add support for provider hooks

- [Breaking] Remove IFeatureProvider interface infavor of FeatureProvider abstract class so default implementations can exist - Make sure Provider hooks are called in the correct order - Use strick mocking mode so sequence is validated correctly - Update test cases for provider hooks support Signed-off-by: Benjamin Evenson <[email protected]>
open-feature · Aug 9, 2022 · 8cb5f6b · 8cb5f6b
1 parent aae53c6
commit 8cb5f6b
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Showing 11 changed files with 268 additions and 126 deletions.
diff --git a/src/OpenFeature.SDK/IFeatureProvider.cs → src/OpenFeature.SDK/FeatureProvider.cs b/src/OpenFeature.SDK/IFeatureProvider.cs → src/OpenFeature.SDK/FeatureProvider.cs
@@ -1,3 +1,5 @@
+using System;
+using System.Collections.Generic;
 using System.Threading.Tasks;
 using OpenFeature.SDK.Model;
 
@@ -8,13 +10,26 @@ namespace OpenFeature.SDK
     /// A provider acts as the translates layer between the generic feature flag structure to a target feature flag system.
     /// </summary>
     /// <seealso href="https://github.com/open-feature/spec/blob/main/specification/providers.md">Provider specification</seealso>
-    public interface IFeatureProvider
+    public abstract class FeatureProvider
     {
+        /// <summary>
+        /// Gets a immutable list of hooks that belong to the provider.
+        /// By default return a empty list
+        ///
+        /// Executed in the order of hooks
+        /// before: API, Client, Invocation, Provider
+        /// after: Provider, Invocation, Client, API
+        /// error (if applicable): Provider, Invocation, Client, API
+        /// finally: Provider, Invocation, Client, API
+        /// </summary>
+        /// <returns></returns>
+        public virtual IReadOnlyList<Hook> GetProviderHooks() => Array.Empty<Hook>();
+
         /// <summary>
         /// Metadata describing the provider.
         /// </summary>
         /// <returns><see cref="Metadata"/></returns>
-        Metadata GetMetadata();
+        public abstract Metadata GetMetadata();
 
         /// <summary>
         /// Resolves a boolean feature flag
@@ -24,7 +39,7 @@ public interface IFeatureProvider
         /// <param name="context"><see cref="EvaluationContext"/></param>
         /// <param name="config"><see cref="FlagEvaluationOptions"/></param>
         /// <returns><see cref="ResolutionDetails{T}"/></returns>
-        Task<ResolutionDetails<bool>> ResolveBooleanValue(string flagKey, bool defaultValue,
+        public abstract Task<ResolutionDetails<bool>> ResolveBooleanValue(string flagKey, bool defaultValue,
             EvaluationContext context = null, FlagEvaluationOptions config = null);
 
         /// <summary>
@@ -35,7 +50,7 @@ Task<ResolutionDetails<bool>> ResolveBooleanValue(string flagKey, bool defaultVa
         /// <param name="context"><see cref="EvaluationContext"/></param>
         /// <param name="config"><see cref="FlagEvaluationOptions"/></param>
         /// <returns><see cref="ResolutionDetails{T}"/></returns>
-        Task<ResolutionDetails<string>> ResolveStringValue(string flagKey, string defaultValue,
+        public abstract Task<ResolutionDetails<string>> ResolveStringValue(string flagKey, string defaultValue,
             EvaluationContext context = null, FlagEvaluationOptions config = null);
 
         /// <summary>
@@ -46,7 +61,7 @@ Task<ResolutionDetails<string>> ResolveStringValue(string flagKey, string defaul
         /// <param name="context"><see cref="EvaluationContext"/></param>
         /// <param name="config"><see cref="FlagEvaluationOptions"/></param>
         /// <returns><see cref="ResolutionDetails{T}"/></returns>
-        Task<ResolutionDetails<int>> ResolveIntegerValue(string flagKey, int defaultValue,
+        public abstract Task<ResolutionDetails<int>> ResolveIntegerValue(string flagKey, int defaultValue,
             EvaluationContext context = null, FlagEvaluationOptions config = null);
 
         /// <summary>
@@ -57,7 +72,7 @@ Task<ResolutionDetails<int>> ResolveIntegerValue(string flagKey, int defaultValu
         /// <param name="context"><see cref="EvaluationContext"/></param>
         /// <param name="config"><see cref="FlagEvaluationOptions"/></param>
         /// <returns><see cref="ResolutionDetails{T}"/></returns>
-        Task<ResolutionDetails<double>> ResolveDoubleValue(string flagKey, double defaultValue,
+        public abstract Task<ResolutionDetails<double>> ResolveDoubleValue(string flagKey, double defaultValue,
             EvaluationContext context = null, FlagEvaluationOptions config = null);
 
         /// <summary>
@@ -69,7 +84,7 @@ Task<ResolutionDetails<double>> ResolveDoubleValue(string flagKey, double defaul
         /// <param name="config"><see cref="FlagEvaluationOptions"/></param>
         /// <typeparam name="T">Type of object</typeparam>
         /// <returns><see cref="ResolutionDetails{T}"/></returns>
-        Task<ResolutionDetails<T>> ResolveStructureValue<T>(string flagKey, T defaultValue,
+        public abstract Task<ResolutionDetails<T>> ResolveStructureValue<T>(string flagKey, T defaultValue,
             EvaluationContext context = null, FlagEvaluationOptions config = null);
     }
 }
diff --git a/src/OpenFeature.SDK/Model/ResolutionDetails.cs b/src/OpenFeature.SDK/Model/ResolutionDetails.cs
@@ -3,7 +3,7 @@
 namespace OpenFeature.SDK.Model
 {
     /// <summary>
-    /// Defines the contract that the <see cref="IFeatureProvider"/> is required to return
+    /// Defines the contract that the <see cref="FeatureProvider"/> is required to return
     /// Describes the details of the feature flag being evaluated
     /// </summary>
     /// <typeparam name="T">Flag value type</typeparam>

diff --git a/src/OpenFeature.SDK/NoOpProvider.cs b/src/OpenFeature.SDK/NoOpProvider.cs
@@ -4,37 +4,37 @@
 
 namespace OpenFeature.SDK
 {
-    internal class NoOpFeatureProvider : IFeatureProvider
+    internal class NoOpFeatureProvider : FeatureProvider
     {
         private readonly Metadata _metadata = new Metadata(NoOpProvider.NoOpProviderName);
 
-        public Metadata GetMetadata()
+        public override Metadata GetMetadata()
         {
             return this._metadata;
         }
 
-        public Task<ResolutionDetails<bool>> ResolveBooleanValue(string flagKey, bool defaultValue, EvaluationContext context = null, FlagEvaluationOptions config = null)
+        public override Task<ResolutionDetails<bool>> ResolveBooleanValue(string flagKey, bool defaultValue, EvaluationContext context = null, FlagEvaluationOptions config = null)
         {
             return Task.FromResult(NoOpResponse(flagKey, defaultValue));
         }
 
-        public Task<ResolutionDetails<string>> ResolveStringValue(string flagKey, string defaultValue, EvaluationContext context = null, FlagEvaluationOptions config = null)
+        public override Task<ResolutionDetails<string>> ResolveStringValue(string flagKey, string defaultValue, EvaluationContext context = null, FlagEvaluationOptions config = null)
         {
             return Task.FromResult(NoOpResponse(flagKey, defaultValue));
         }
 
-        public Task<ResolutionDetails<int>> ResolveIntegerValue(string flagKey, int defaultValue, EvaluationContext context = null, FlagEvaluationOptions config = null)
+        public override Task<ResolutionDetails<int>> ResolveIntegerValue(string flagKey, int defaultValue, EvaluationContext context = null, FlagEvaluationOptions config = null)
         {
             return Task.FromResult(NoOpResponse(flagKey, defaultValue));
         }
 
-        public Task<ResolutionDetails<double>> ResolveDoubleValue(string flagKey, double defaultValue, EvaluationContext context = null,
+        public override Task<ResolutionDetails<double>> ResolveDoubleValue(string flagKey, double defaultValue, EvaluationContext context = null,
             FlagEvaluationOptions config = null)
         {
             return Task.FromResult(NoOpResponse(flagKey, defaultValue));
         }
 
-        public Task<ResolutionDetails<T>> ResolveStructureValue<T>(string flagKey, T defaultValue, EvaluationContext context = null, FlagEvaluationOptions config = null)
+        public override Task<ResolutionDetails<T>> ResolveStructureValue<T>(string flagKey, T defaultValue, EvaluationContext context = null, FlagEvaluationOptions config = null)
         {
             return Task.FromResult(NoOpResponse(flagKey, defaultValue));
         }

diff --git a/src/OpenFeature.SDK/OpenFeature.cs b/src/OpenFeature.SDK/OpenFeature.cs
@@ -12,7 +12,7 @@ namespace OpenFeature.SDK
     public sealed class OpenFeature
     {
         private EvaluationContext _evaluationContext = new EvaluationContext();
-        private IFeatureProvider _featureProvider = new NoOpFeatureProvider();
+        private FeatureProvider _featureProvider = new NoOpFeatureProvider();
         private readonly List<Hook> _hooks = new List<Hook>();
 
         /// <summary>
@@ -29,14 +29,14 @@ private OpenFeature() { }
         /// <summary>
         /// Sets the feature provider
         /// </summary>
-        /// <param name="featureProvider">Implementation of <see cref="IFeatureProvider"/></param>
-        public void SetProvider(IFeatureProvider featureProvider) => this._featureProvider = featureProvider;
+        /// <param name="featureProvider">Implementation of <see cref="FeatureProvider"/></param>
+        public void SetProvider(FeatureProvider featureProvider) => this._featureProvider = featureProvider;
 
         /// <summary>
         /// Gets the feature provider
         /// </summary>
-        /// <returns><see cref="IFeatureProvider"/></returns>
-        public IFeatureProvider GetProvider() => this._featureProvider;
+        /// <returns><see cref="FeatureProvider"/></returns>
+        public FeatureProvider GetProvider() => this._featureProvider;
 
         /// <summary>
         /// Gets providers metadata
@@ -81,7 +81,7 @@ public FeatureClient GetClient(string name = null, string version = null, ILogge
         /// Sets the global <see cref="EvaluationContext"/>
         /// </summary>
         /// <param name="context"></param>
-        public void SetContext(EvaluationContext context) => this._evaluationContext = context;
+        public void SetContext(EvaluationContext context) => this._evaluationContext = context ?? new EvaluationContext();
 
         /// <summary>
         /// Gets the global <see cref="EvaluationContext"/>

diff --git a/src/OpenFeature.SDK/OpenFeatureClient.cs b/src/OpenFeature.SDK/OpenFeatureClient.cs
@@ -17,19 +17,19 @@ namespace OpenFeature.SDK
     public sealed class FeatureClient : IFeatureClient
     {
         private readonly ClientMetadata _metadata;
-        private readonly IFeatureProvider _featureProvider;
+        private readonly FeatureProvider _featureProvider;
         private readonly List<Hook> _hooks = new List<Hook>();
         private readonly ILogger _logger;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="FeatureClient"/> class.
         /// </summary>
-        /// <param name="featureProvider">Feature provider used by client <see cref="IFeatureProvider"/></param>
+        /// <param name="featureProvider">Feature provider used by client <see cref="FeatureProvider"/></param>
         /// <param name="name">Name of client <see cref="ClientMetadata"/></param>
         /// <param name="version">Version of client <see cref="ClientMetadata"/></param>
         /// <param name="logger">Logger used by client</param>
         /// <exception cref="ArgumentNullException">Throws if any of the required parameters are null</exception>
-        public FeatureClient(IFeatureProvider featureProvider, string name, string version, ILogger logger = null)
+        public FeatureClient(FeatureProvider featureProvider, string name, string version, ILogger logger = null)
         {
             this._featureProvider = featureProvider ?? throw new ArgumentNullException(nameof(featureProvider));
             this._metadata = new ClientMetadata(name, version);
@@ -209,6 +209,7 @@ private async Task<FlagEvaluationDetails<T>> EvaluateFlag<T>(
                 .Concat(OpenFeature.Instance.GetHooks())
                 .Concat(this._hooks)
                 .Concat(options?.Hooks ?? Enumerable.Empty<Hook>())
+                .Concat(this._featureProvider.GetProviderHooks())
                 .ToList()
                 .AsReadOnly();
 

diff --git a/test/OpenFeature.SDK.Tests/ClearOpenFeatureInstanceFixture.cs b/test/OpenFeature.SDK.Tests/ClearOpenFeatureInstanceFixture.cs
@@ -0,0 +1,13 @@
+namespace OpenFeature.SDK.Tests
+{
+    public class ClearOpenFeatureInstanceFixture
+    {
+        // Make sure the singleton is cleared between tests
+        public ClearOpenFeatureInstanceFixture()
+        {
+            OpenFeature.Instance.SetContext(null);
+            OpenFeature.Instance.ClearHooks();
+            OpenFeature.Instance.SetProvider(new NoOpFeatureProvider());
+        }
+    }
+}
diff --git a/test/OpenFeature.SDK.Tests/FeatureProviderTests.cs b/test/OpenFeature.SDK.Tests/FeatureProviderTests.cs
@@ -9,7 +9,7 @@
 
 namespace OpenFeature.SDK.Tests
 {
-    public class FeatureProviderTests
+    public class FeatureProviderTests : ClearOpenFeatureInstanceFixture
     {
         [Fact]
         [Specification("2.1", "The provider interface MUST define a `metadata` member or accessor, containing a `name` field or accessor of type string, which identifies the provider implementation.")]
@@ -67,7 +67,7 @@ public async Task Provider_Must_ErrorType()
             var defaultIntegerValue = fixture.Create<int>();
             var defaultDoubleValue = fixture.Create<double>();
             var defaultStructureValue = fixture.Create<TestStructure>();
-            var providerMock = new Mock<IFeatureProvider>();
+            var providerMock = new Mock<FeatureProvider>(MockBehavior.Strict);
 
             providerMock.Setup(x => x.ResolveBooleanValue(flagName, defaultBoolValue, It.IsAny<EvaluationContext>(), It.IsAny<FlagEvaluationOptions>()))
                 .ReturnsAsync(new ResolutionDetails<bool>(flagName, defaultBoolValue, ErrorType.General, NoOpProvider.ReasonNoOp, NoOpProvider.Variant));