fix: update DI lifecycle to use container instead of static instance (#534)

* feat: Update Api constructor visibility and adjust service registration

Signed-off-by: André Silva <[email protected]>

* feat: Enhance FeatureClient to use Api instance for provider access and context retrieval

Signed-off-by: André Silva <[email protected]>

* feat: Update Api to support singleton instance setup in Dependency Injection

Signed-off-by: André Silva <[email protected]>

* feat: Refactor FeatureClient constructor to prioritize API instance and improve provider access

Signed-off-by: André Silva <[email protected]>

---------

Signed-off-by: André Silva <[email protected]>

Author: askpt

src/OpenFeature.DependencyInjection/OpenFeatureServiceCollectionExtensions.cs

@@ -24,7 +24,9 @@ public static IServiceCollection AddOpenFeature(this IServiceCollection services
         Guard.ThrowIfNull(configure);
 
         // Register core OpenFeature services as singletons.
-        services.TryAddSingleton(Api.Instance);
+        var api = new Api();
+        Api.SetInstance(api);
+        services.TryAddSingleton(api);
         services.TryAddSingleton<IFeatureLifecycleManager, FeatureLifecycleManager>();
 
         var builder = new OpenFeatureBuilder(services);

src/OpenFeature/Api.cs

@@ -32,7 +32,7 @@ public sealed class Api : IEventBus
     // not to mark type as beforeFieldInit
     // IE Lazy way of ensuring this is thread safe without using locks
     static Api() { }
-    private Api() { }
+    internal Api() { }
 
     /// <summary>
     /// Sets the default feature provider. In order to wait for the provider to be set, and initialization to complete,
@@ -121,7 +121,7 @@ public FeatureProvider GetProvider(string domain)
     /// <returns><see cref="FeatureClient"/></returns>
     public FeatureClient GetClient(string? name = null, string? version = null, ILogger? logger = null,
         EvaluationContext? context = null) =>
-        new FeatureClient(() => this._repository.GetProvider(name), name, version, logger, context);
+        new FeatureClient(this, () => this._repository.GetProvider(name), name, version, logger, context);
 
     /// <summary>
     /// Appends list of hooks to global hooks list
@@ -360,4 +360,12 @@ internal static void ResetApi()
     {
         Instance = new Api();
     }
+
+    /// <summary>
+    /// This method should only be used in the Dependency Injection setup. It will set the singleton instance of the API using the provided instance.
+    /// </summary>
+    internal static void SetInstance(Api api)
+    {
+        Instance = api;
+    }
 }

src/OpenFeature/OpenFeature.csproj

@@ -19,7 +19,8 @@
     <InternalsVisibleTo Include="OpenFeature.Benchmarks" />
     <InternalsVisibleTo Include="OpenFeature.Tests" />
     <InternalsVisibleTo Include="OpenFeature.E2ETests" />
+    <InternalsVisibleTo Include="OpenFeature.DependencyInjection" />
     <None Include="../../README.md" Pack="true" PackagePath="/" />
   </ItemGroup>
 
-</Project>
+</Project>

src/OpenFeature/OpenFeatureClient.cs

@@ -18,6 +18,7 @@ public sealed partial class FeatureClient : IFeatureClient
     private readonly ConcurrentStack<Hook> _hooks = new ConcurrentStack<Hook>();
     private readonly ILogger _logger;
     private readonly Func<FeatureProvider> _providerAccessor;
+    private readonly Api _api;
     private EvaluationContext _evaluationContext;
 
     private readonly object _evaluationContextLock = new object();
@@ -40,7 +41,7 @@ public sealed partial class FeatureClient : IFeatureClient
     {
         // Alias the provider reference so getting the method and returning the provider are
         // guaranteed to be the same object.
-        var provider = Api.Instance.GetProvider(this._metadata.Name!);
+        var provider = this._api.GetProvider(this._metadata.Name!);
 
         return (method(provider), provider);
     }
@@ -69,18 +70,20 @@ public void SetContext(EvaluationContext? context)
     /// <summary>
     /// Initializes a new instance of the <see cref="FeatureClient"/> class.
     /// </summary>
+    /// <param name="api">The API instance for accessing global state and providers</param>
     /// <param name="providerAccessor">Function to retrieve current provider</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>
     /// <param name="context">Context given to this client</param>
     /// <exception cref="ArgumentNullException">Throws if any of the required parameters are null</exception>
-    internal FeatureClient(Func<FeatureProvider> providerAccessor, string? name, string? version, ILogger? logger = null, EvaluationContext? context = null)
+    internal FeatureClient(Api api, Func<FeatureProvider> providerAccessor, string? name, string? version, ILogger? logger = null, EvaluationContext? context = null)
     {
+        this._api = api;
+        this._providerAccessor = providerAccessor;
         this._metadata = new ClientMetadata(name, version);
         this._logger = logger ?? NullLogger<FeatureClient>.Instance;
         this._evaluationContext = context ?? EvaluationContext.Empty;
-        this._providerAccessor = providerAccessor;
     }
 
     /// <inheritdoc />
@@ -99,13 +102,13 @@ internal FeatureClient(Func<FeatureProvider> providerAccessor, string? name, str
     /// <inheritdoc />
     public void AddHandler(ProviderEventTypes eventType, EventHandlerDelegate handler)
     {
-        Api.Instance.AddClientHandler(this._metadata.Name!, eventType, handler);
+        this._api.AddClientHandler(this._metadata.Name!, eventType, handler);
     }
 
     /// <inheritdoc />
     public void RemoveHandler(ProviderEventTypes type, EventHandlerDelegate handler)
     {
-        Api.Instance.RemoveClientHandler(this._metadata.Name!, type, handler);
+        this._api.RemoveClientHandler(this._metadata.Name!, type, handler);
     }
 
     /// <inheritdoc />
@@ -213,13 +216,13 @@ private async Task<FlagEvaluationDetails<T>> EvaluateFlagAsync<T>(
 
         // merge api, client, transaction and invocation context
         var evaluationContextBuilder = EvaluationContext.Builder();
-        evaluationContextBuilder.Merge(Api.Instance.GetContext()); // API context
+        evaluationContextBuilder.Merge(this._api.GetContext()); // API context
         evaluationContextBuilder.Merge(this.GetContext()); // Client context
-        evaluationContextBuilder.Merge(Api.Instance.GetTransactionContext()); // Transaction context
+        evaluationContextBuilder.Merge(this._api.GetTransactionContext()); // Transaction context
         evaluationContextBuilder.Merge(context); // Invocation context
 
         var allHooks = ImmutableList.CreateBuilder<Hook>()
-            .Concat(Api.Instance.GetHooks())
+            .Concat(this._api.GetHooks())
             .Concat(this.GetHooks())
             .Concat(options?.Hooks ?? Enumerable.Empty<Hook>())
             .Concat(provider.GetProviderHooks())
@@ -310,7 +313,7 @@ public void Track(string trackingEventName, EvaluationContext? evaluationContext
             throw new ArgumentException("Tracking event cannot be null or empty.", nameof(trackingEventName));
         }
 
-        var globalContext = Api.Instance.GetContext();
+        var globalContext = this._api.GetContext();
         var clientContext = this.GetContext();
 
         var evaluationContextBuilder = EvaluationContext.Builder()