API that allows to remove all resilience handlers from the HTTP client (

#5801)

* Add API to clear the http client resilience handlers

* Additional tests

* Add experimental attribute to the new API

* Fix formatting

* Add the check for the handler type, formatting

* Formatting

* Additional test to ensure that new API removes only resilience handlers

* Review fixes

* Review fixes

src/Libraries/Microsoft.Extensions.Http.Resilience/Resilience/ResilienceHttpClientBuilderExtensions.Resilience.cs

@@ -2,11 +2,13 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Net.Http;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Diagnostics.ExceptionSummarization;
 using Microsoft.Extensions.Http.Resilience;
 using Microsoft.Extensions.Http.Resilience.Internal;
+using Microsoft.Shared.DiagnosticIds;
 using Microsoft.Shared.Diagnostics;
 using Polly;
 using Polly.Registry;
@@ -75,6 +77,28 @@ public static IHttpResiliencePipelineBuilder AddResilienceHandler(
         return pipelineBuilder;
     }
 
+    /// <summary>
+    /// Removes all resilience handlers registered earlier.
+    /// </summary>
+    /// <param name="builder">The builder instance.</param>
+    /// <returns>The value of <paramref name="builder"/>.</returns>
+    [Experimental(diagnosticId: DiagnosticIds.Experiments.Resilience, UrlFormat = DiagnosticIds.UrlFormat)]
+    public static IHttpClientBuilder RemoveAllResilienceHandlers(this IHttpClientBuilder builder)
+    {
+        _ = Throw.IfNull(builder);
+        _ = builder.ConfigureAdditionalHttpMessageHandlers(static (handlers, _) =>
+        {
+            for (int i = handlers.Count - 1; i >= 0; i--)
+            {
+                if (handlers[i] is ResilienceHandler)
+                {
+                    handlers.RemoveAt(i);
+                }
+            }
+        });
+        return builder;
+    }
+
     private static Func<HttpRequestMessage, ResiliencePipeline<HttpResponseMessage>> CreatePipelineSelector(IServiceProvider serviceProvider, string pipelineName)
     {
         var resilienceProvider = serviceProvider.GetRequiredService<ResiliencePipelineProvider<HttpKey>>();

test/Libraries/Microsoft.Extensions.Http.Resilience.Tests/Resilience/HttpClientBuilderExtensionsTests.Resilience.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Net;
 using System.Net.Http;
 using System.Threading.Tasks;
@@ -286,6 +287,77 @@ public void AddResilienceHandler_AuthorityByCustomSelector_NotValidated()
         Assert.NotNull(factory.CreateClient("my-client"));
     }
 
+    [Fact]
+    public void RemoveAllResilienceHandlers_ArgumentValidation()
+    {
+        var services = new ServiceCollection();
+        IHttpClientBuilder? builder = null;
+        Assert.Throws<ArgumentNullException>(() => builder!.RemoveAllResilienceHandlers());
+    }
+
+    [Fact]
+    public void RemoveAllResilienceHandlers_EnsureHandlersRemoved()
+    {
+        var services = new ServiceCollection();
+
+        IHttpClientBuilder? builder = services.AddHttpClient("custom");
+
+        builder.AddStandardResilienceHandler();
+
+        builder.ConfigureAdditionalHttpMessageHandlers((handlers, _) =>
+        {
+            Assert.Single(handlers);
+        });
+
+        builder.RemoveAllResilienceHandlers();
+
+        builder.ConfigureAdditionalHttpMessageHandlers((handlers, _) =>
+        {
+            Assert.Empty(handlers);
+        });
+
+        using ServiceProvider serviceProvider = services.BuildServiceProvider();
+        serviceProvider.GetRequiredService<IHttpClientFactory>().CreateClient("custom");
+    }
+
+    [Fact]
+    public void RemoveAllResilienceHandlers_AddHandlersAfterRemoval()
+    {
+        var services = new ServiceCollection();
+
+        IHttpClientBuilder? builder = services.AddHttpClient("custom");
+        builder.RemoveAllResilienceHandlers().AddStandardResilienceHandler();
+        builder.ConfigureAdditionalHttpMessageHandlers((handlers, _) =>
+        {
+            Assert.Single(handlers);
+        });
+
+        using ServiceProvider serviceProvider = services.BuildServiceProvider();
+        serviceProvider.GetRequiredService<IHttpClientFactory>().CreateClient("custom");
+    }
+
+    [Fact]
+    public void RemoveAllResilienceHandlers_EnsureOnlyResilienceHandlersRemoved()
+    {
+        var services = new ServiceCollection();
+
+        IHttpClientBuilder? builder = services.AddHttpClient("custom");
+
+        builder.AddHttpMessageHandler(() => new TestHandlerStub(HttpStatusCode.OK));
+        builder.AddStandardResilienceHandler();
+
+        builder.RemoveAllResilienceHandlers();
+
+        builder.ConfigureAdditionalHttpMessageHandlers((handlers, _) =>
+        {
+            Assert.Single(handlers);
+            Assert.Equal(typeof(TestHandlerStub), handlers.First().GetType());
+        });
+
+        using ServiceProvider serviceProvider = services.BuildServiceProvider();
+        serviceProvider.GetRequiredService<IHttpClientFactory>().CreateClient("custom");
+    }
+
     private void ConfigureBuilder(ResiliencePipelineBuilder<HttpResponseMessage> builder) => builder.AddTimeout(TimeSpan.FromSeconds(1));
 
     private class TestMetricsEnricher : MeteringEnricher