Service Discovery API refactoring (#3114)

* API review feedback & general cleanup including removal of currently unused features

* Align namespaces

* Hide more of the API, rename for consistency

* Hide more, rename more

* ResolutionStatus does not need to be equatable

* Make ServiceEndPointQuery public to break InternalsVisibleTo with Dns provider

* Break InternalsVisibleTo from ServiceDiscovery package to YARP by adding a middleware factory

* Remove ResolutionStatus, simplifying Service Discovery interfaces

* Clean up ServiceEndPointImpl

* Mark ServiceEndPointResolverResult as internal

* Remove unnecessary members from ServiceEndPointCollection/Source

* Seal service discovery types

* Remove IServiceEndPointSelectorFactory and use DI instead

* Remove unused endpoint selectors

* Remove unused PendingStatusRefreshPeriod option

* Rename UseServiceDiscovery to AddServiceDiscovery

* Remove possible ambiguity in AddConfigurationServiceEndPointResolver signature

* Add configuration delegate overloads to AddServiceDiscovery methods

* Clean up logging in configuration-based service endpoint provider

* API review: rename ServiceEndPointCollectionSource to IServiceEndPointBuilder

* Rename IServiceDiscoveryDelegatingHttpMessageHandlerFactory

* Rename IServiceEndPointProvider.ResolveAsync to PopulateAsync

* Hide IServiceEndPointSelector

* Remove allowedSchemes from ServiceEndPointQuery.TryParse

* Rename ServiceEndPointQuery.Host to .ServiceName

* Fix build

* Review feedback

* nit param rename

* Improve ServiceEndPointQuery.ToString output

* fixup

playground/AWS/AWS.ServiceDefaults/Extensions.cs

@@ -28,7 +28,7 @@ public static IHostApplicationBuilder AddServiceDefaults(this IHostApplicationBu
             http.AddStandardResilienceHandler();
 
             // Turn on service discovery by default
-            http.UseServiceDiscovery();
+            http.AddServiceDiscovery();
         });
 
         // Uncomment the following to restrict the allowed schemes for service discovery.

playground/Playground.ServiceDefaults/Extensions.cs

@@ -28,7 +28,7 @@ public static IHostApplicationBuilder AddServiceDefaults(this IHostApplicationBu
             http.AddStandardResilienceHandler();
 
             // Turn on service discovery by default
-            http.UseServiceDiscovery();
+            http.AddServiceDiscovery();
         });
 
         // Uncomment the following to restrict the allowed schemes for service discovery.

playground/TestShop/ServiceDefaults/Extensions.cs

@@ -25,7 +25,7 @@ public static IHostApplicationBuilder AddServiceDefaults(this IHostApplicationBu
             http.AddStandardResilienceHandler();
 
             // Turn on service discovery by default
-            http.UseServiceDiscovery();
+            http.AddServiceDiscovery();
         });
 
         // Uncomment the following to restrict the allowed schemes for service discovery.

playground/orleans/OrleansServiceDefaults/Extensions.cs

@@ -25,7 +25,7 @@ public static IHostApplicationBuilder AddServiceDefaults(this IHostApplicationBu
             http.AddStandardResilienceHandler();
 
             // Turn on service discovery by default
-            http.UseServiceDiscovery();
+            http.AddServiceDiscovery();
         });
 
         // Uncomment the following to restrict the allowed schemes for service discovery.

playground/seq/Seq.ServiceDefaults/Extensions.cs

@@ -29,7 +29,7 @@ public static IHostApplicationBuilder AddServiceDefaults(this IHostApplicationBu
             http.AddStandardResilienceHandler();
 
             // Turn on service discovery by default
-            http.UseServiceDiscovery();
+            http.AddServiceDiscovery();
         });
 
         // Uncomment the following to restrict the allowed schemes for service discovery.

src/Microsoft.Extensions.ServiceDiscovery.Abstractions/Features/IHostNameFeature.cs → src/Microsoft.Extensions.ServiceDiscovery.Abstractions/IHostNameFeature.cs

@@ -1,7 +1,7 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-namespace Microsoft.Extensions.ServiceDiscovery.Abstractions;
+namespace Microsoft.Extensions.ServiceDiscovery;
 
 /// <summary>
 /// Exposes the host name of the end point.

src/Microsoft.Extensions.ServiceDiscovery.Abstractions/IServiceEndPointBuilder.cs

@@ -0,0 +1,29 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.Primitives;
+
+namespace Microsoft.Extensions.ServiceDiscovery;
+
+/// <summary>
+/// Builder to create a <see cref="ServiceEndPointSource"/> instances.
+/// </summary>
+public interface IServiceEndPointBuilder
+{
+    /// <summary>
+    /// Gets the endpoints.
+    /// </summary>
+    IList<ServiceEndPoint> EndPoints { get; }
+
+    /// <summary>
+    /// Gets the feature collection.
+    /// </summary>
+    IFeatureCollection Features { get; }
+
+    /// <summary>
+    /// Adds a change token to the resulting <see cref="ServiceEndPointSource"/>.
+    /// </summary>
+    /// <param name="changeToken">The change token.</param>
+    void AddChangeToken(IChangeToken changeToken);
+}

src/Microsoft.Extensions.ServiceDiscovery.Abstractions/IServiceEndPointProvider.cs

@@ -1,7 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-namespace Microsoft.Extensions.ServiceDiscovery.Abstractions;
+namespace Microsoft.Extensions.ServiceDiscovery;
 
 /// <summary>
 /// Provides details about a service's endpoints.
@@ -14,5 +14,5 @@ public interface IServiceEndPointProvider : IAsyncDisposable
     /// <param name="endPoints">The endpoint collection, which resolved endpoints will be added to.</param>
     /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
     /// <returns>The resolution status.</returns>
-    ValueTask<ResolutionStatus> ResolveAsync(ServiceEndPointCollectionSource endPoints, CancellationToken cancellationToken);
+    ValueTask PopulateAsync(IServiceEndPointBuilder endPoints, CancellationToken cancellationToken);
 }

src/Microsoft.Extensions.ServiceDiscovery.Abstractions/IServiceEndPointResolverProvider.cs → src/Microsoft.Extensions.ServiceDiscovery.Abstractions/IServiceEndPointProviderFactory.cs

@@ -3,18 +3,18 @@
 
 using System.Diagnostics.CodeAnalysis;
 
-namespace Microsoft.Extensions.ServiceDiscovery.Abstractions;
+namespace Microsoft.Extensions.ServiceDiscovery;
 
 /// <summary>
 /// Creates <see cref="IServiceEndPointProvider"/> instances.
 /// </summary>
-public interface IServiceEndPointResolverProvider
+public interface IServiceEndPointProviderFactory
 {
     /// <summary>
-    /// Tries to create an <see cref="IServiceEndPointProvider"/> instance for the specified <paramref name="serviceName"/>.
+    /// Tries to create an <see cref="IServiceEndPointProvider"/> instance for the specified <paramref name="query"/>.
     /// </summary>
-    /// <param name="serviceName">The service to create the resolver for.</param>
+    /// <param name="query">The service to create the resolver for.</param>
     /// <param name="resolver">The resolver.</param>
     /// <returns><see langword="true"/> if the resolver was created, <see langword="false"/> otherwise.</returns>
-    bool TryCreateResolver(string serviceName, [NotNullWhen(true)] out IServiceEndPointProvider? resolver);
+    bool TryCreateProvider(ServiceEndPointQuery query, [NotNullWhen(true)] out IServiceEndPointProvider? resolver);
 }

src/Microsoft.Extensions.ServiceDiscovery.Abstractions/Internal/ServiceEndPointImpl.cs

@@ -4,21 +4,11 @@
 using System.Net;
 using Microsoft.AspNetCore.Http.Features;
 
-namespace Microsoft.Extensions.ServiceDiscovery.Abstractions;
+namespace Microsoft.Extensions.ServiceDiscovery.Internal;
 
-internal sealed class ServiceEndPointImpl : ServiceEndPoint
+internal sealed class ServiceEndPointImpl(EndPoint endPoint, IFeatureCollection? features = null) : ServiceEndPoint
 {
-    private readonly IFeatureCollection _features;
-    private readonly EndPoint _endPoint;
-
-    public ServiceEndPointImpl(EndPoint endPoint, IFeatureCollection? features = null)
-    {
-        _endPoint = endPoint;
-        _features = features ?? new FeatureCollection();
-    }
-
-    public override EndPoint EndPoint => _endPoint;
-    public override IFeatureCollection Features => _features;
-
+    public override EndPoint EndPoint { get; } = endPoint;
+    public override IFeatureCollection Features { get; } = features ?? new FeatureCollection();
     public override string? ToString() => GetEndPointString();
 }

src/Microsoft.Extensions.ServiceDiscovery.Abstractions/ServiceEndPoint.cs

@@ -4,8 +4,9 @@
 using System.Diagnostics;
 using System.Net;
 using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.ServiceDiscovery.Internal;
 
-namespace Microsoft.Extensions.ServiceDiscovery.Abstractions;
+namespace Microsoft.Extensions.ServiceDiscovery;
 
 /// <summary>
 /// Represents an endpoint for a service.