start of request queue

eng/ProjectReferences.props

@@ -79,6 +79,7 @@
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.HttpOverrides" ProjectPath="$(RepoRoot)src\Middleware\HttpOverrides\src\Microsoft.AspNetCore.HttpOverrides.csproj" RefProjectPath="$(RepoRoot)src\Middleware\HttpOverrides\ref\Microsoft.AspNetCore.HttpOverrides.csproj" />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.HttpsPolicy" ProjectPath="$(RepoRoot)src\Middleware\HttpsPolicy\src\Microsoft.AspNetCore.HttpsPolicy.csproj" RefProjectPath="$(RepoRoot)src\Middleware\HttpsPolicy\ref\Microsoft.AspNetCore.HttpsPolicy.csproj" />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.Localization.Routing" ProjectPath="$(RepoRoot)src\Middleware\Localization.Routing\src\Microsoft.AspNetCore.Localization.Routing.csproj" RefProjectPath="$(RepoRoot)src\Middleware\Localization.Routing\ref\Microsoft.AspNetCore.Localization.Routing.csproj" />
+    <ProjectReferenceProvider Include="Microsoft.AspNetCore.RequestQueue" ProjectPath="$(RepositoryRoot)src\Middleware\RequestQueue\src\Microsoft.AspNetCore.RequestQueue.csproj" RefProjectPath="$(RepositoryRoot)src\Middleware\RequestQueue\ref\Microsoft.AspNetCore.RequestQueue.csproj" />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.Localization" ProjectPath="$(RepoRoot)src\Middleware\Localization\src\Microsoft.AspNetCore.Localization.csproj" RefProjectPath="$(RepoRoot)src\Middleware\Localization\ref\Microsoft.AspNetCore.Localization.csproj" />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.MiddlewareAnalysis" ProjectPath="$(RepoRoot)src\Middleware\MiddlewareAnalysis\src\Microsoft.AspNetCore.MiddlewareAnalysis.csproj" RefProjectPath="$(RepoRoot)src\Middleware\MiddlewareAnalysis\ref\Microsoft.AspNetCore.MiddlewareAnalysis.csproj" />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.NodeServices" ProjectPath="$(RepoRoot)src\Middleware\NodeServices\src\Microsoft.AspNetCore.NodeServices.csproj" RefProjectPath="$(RepoRoot)src\Middleware\NodeServices\ref\Microsoft.AspNetCore.NodeServices.csproj" />

src/Middleware/RequestQueue/ref/Microsoft.AspNetCore.RequestQueue.csproj

@@ -0,0 +1,14 @@
+<!-- This file is automatically generated. -->
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>netcoreapp3.0</TargetFrameworks>
+  </PropertyGroup>
+  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+    <Compile Include="Microsoft.AspNetCore.HttpsPolicy.netcoreapp3.0.cs" />
+    <Reference Include="Microsoft.AspNetCore.Http"  />
+    <Reference Include="Microsoft.AspNetCore.Http.Extensions"  />
+    <Reference Include="Microsoft.Extensions.Configuration.Binder"  />
+    <Reference Include="Microsoft.Extensions.Options"  />
+    <Reference Include="Microsoft.AspNetCore.Hosting.Abstractions"  />
+  </ItemGroup>
+</Project>

src/Middleware/RequestQueue/ref/Microsoft.AspNetCore.RequestQueue.netcoreapp3.0.cs

@@ -0,0 +1,51 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNetCore.Builder
+{
+    public static partial class HstsBuilderExtensions
+    {
+        public static Microsoft.AspNetCore.Builder.IApplicationBuilder UseHsts(this Microsoft.AspNetCore.Builder.IApplicationBuilder app) { throw null; }
+    }
+    public static partial class HstsServicesExtensions
+    {
+        public static Microsoft.Extensions.DependencyInjection.IServiceCollection AddHsts(this Microsoft.Extensions.DependencyInjection.IServiceCollection services, System.Action<Microsoft.AspNetCore.HttpsPolicy.HstsOptions> configureOptions) { throw null; }
+    }
+    public static partial class HttpsPolicyBuilderExtensions
+    {
+        public static Microsoft.AspNetCore.Builder.IApplicationBuilder UseHttpsRedirection(this Microsoft.AspNetCore.Builder.IApplicationBuilder app) { throw null; }
+    }
+    public static partial class HttpsRedirectionServicesExtensions
+    {
+        public static Microsoft.Extensions.DependencyInjection.IServiceCollection AddHttpsRedirection(this Microsoft.Extensions.DependencyInjection.IServiceCollection services, System.Action<Microsoft.AspNetCore.HttpsPolicy.HttpsRedirectionOptions> configureOptions) { throw null; }
+    }
+}
+namespace Microsoft.AspNetCore.HttpsPolicy
+{
+    public partial class HstsMiddleware
+    {
+        public HstsMiddleware(Microsoft.AspNetCore.Http.RequestDelegate next, Microsoft.Extensions.Options.IOptions<Microsoft.AspNetCore.HttpsPolicy.HstsOptions> options) { }
+        public HstsMiddleware(Microsoft.AspNetCore.Http.RequestDelegate next, Microsoft.Extensions.Options.IOptions<Microsoft.AspNetCore.HttpsPolicy.HstsOptions> options, Microsoft.Extensions.Logging.ILoggerFactory loggerFactory) { }
+        public System.Threading.Tasks.Task Invoke(Microsoft.AspNetCore.Http.HttpContext context) { throw null; }
+    }
+    public partial class HstsOptions
+    {
+        public HstsOptions() { }
+        public System.Collections.Generic.IList<string> ExcludedHosts { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public bool IncludeSubDomains { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
+        public System.TimeSpan MaxAge { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
+        public bool Preload { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
+    }
+    public partial class HttpsRedirectionMiddleware
+    {
+        public HttpsRedirectionMiddleware(Microsoft.AspNetCore.Http.RequestDelegate next, Microsoft.Extensions.Options.IOptions<Microsoft.AspNetCore.HttpsPolicy.HttpsRedirectionOptions> options, Microsoft.Extensions.Configuration.IConfiguration config, Microsoft.Extensions.Logging.ILoggerFactory loggerFactory) { }
+        public HttpsRedirectionMiddleware(Microsoft.AspNetCore.Http.RequestDelegate next, Microsoft.Extensions.Options.IOptions<Microsoft.AspNetCore.HttpsPolicy.HttpsRedirectionOptions> options, Microsoft.Extensions.Configuration.IConfiguration config, Microsoft.Extensions.Logging.ILoggerFactory loggerFactory, Microsoft.AspNetCore.Hosting.Server.Features.IServerAddressesFeature serverAddressesFeature) { }
+        public System.Threading.Tasks.Task Invoke(Microsoft.AspNetCore.Http.HttpContext context) { throw null; }
+    }
+    public partial class HttpsRedirectionOptions
+    {
+        public HttpsRedirectionOptions() { }
+        public int? HttpsPort { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
+        public int RedirectStatusCode { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
+    }
+}

src/Middleware/RequestQueue/sample/RequestQueueSample.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Reference Include="Microsoft.AspNetCore.Server.Kestrel" />
+    <Reference Include="Microsoft.Extensions.Logging.Console" />
+    <Reference Include="Microsoft.AspNetCore.HttpsPolicy" />
+  </ItemGroup>
+
+</Project>

src/Middleware/RequestQueue/sample/Startup.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Net;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.HttpsPolicy;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace RequestQueueSample
+{
+    public class Startup
+    {
+        // This method gets called by the runtime. Use this method to add services to the container.
+        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
+        public void ConfigureServices(IServiceCollection services)
+        {
+        }
+
+        public void Configure(IApplicationBuilder app, IWebHostEnvironment environment)
+        {
+            app.Run(async context =>
+            {
+                await context.Response.WriteAsync("Hello world!");
+            });
+        }
+
+        // Entry point for the application.
+        public static void Main(string[] args)
+        {
+            var host = new WebHostBuilder()
+                .UseKestrel()
+                .UseContentRoot(Directory.GetCurrentDirectory()) // for the cert file
+                .ConfigureLogging(factory =>
+                {
+                    factory.SetMinimumLevel(LogLevel.Debug);
+                    factory.AddConsole();
+                })
+                .UseStartup<Startup>()
+                .Build();
+
+            host.Run();
+        }
+    }
+}

src/Middleware/RequestQueue/src/Microsoft.AspNetCore.RequestQueue.csproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <Description>ASP.NET Core middleware for queuing incoming HTTP requests, to avoid threadpool starvation.</Description>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
+    <NoWarn>$(NoWarn);CS1591</NoWarn>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+    <WarningsNotAsErrors>$(WarningsNotAsErrors);CS1591</WarningsNotAsErrors>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Reference Include="Microsoft.AspNetCore.Http" />
+    <Reference Include="Microsoft.AspNetCore.Http.Extensions" />
+    <Reference Include="Microsoft.Extensions.Configuration.Binder" />
+    <Reference Include="Microsoft.Extensions.Options" />
+    <Reference Include="Microsoft.AspNetCore.Hosting.Abstractions" />
+  </ItemGroup>
+</Project>

src/Middleware/RequestQueue/src/SemaphoreWrapper.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.RequestQueue
+{
+    internal class SemaphoreWrapper
+    {
+        private static SemaphoreSlim semaphore;
+
+        public SemaphoreWrapper(int qlength)
+        {
+            semaphore = new SemaphoreSlim(qlength);
+        }
+
+        public Task EnterQueue()
+        {
+            return semaphore.WaitAsync();
+        }
+
+        public void LeaveQueue()
+        {
+            semaphore.Release();
+        }
+
+        public int SpotsLeft
+        {
+            get => semaphore.CurrentCount;
+        }
+    }
+}

src/Middleware/RequestQueue/test/Microsoft.AspNetCore.RequestQueue.Tests.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Reference Include="Microsoft.AspNetCore.RequestQueue" />
+  </ItemGroup>
+</Project>

src/Middleware/RequestQueue/test/SemaphoreWrapperTests.cs

@@ -0,0 +1,56 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Xunit;
+using System.Threading;
+using System.Threading.Tasks;
+using System;
+using System.Runtime.CompilerServices;
+using Microsoft.AspNetCore.Testing;
+
+namespace Microsoft.AspNetCore.RequestQueue.Tests
+{
+    public class SemaphoreWrapperTests
+    {
+        [Fact]
+        public async Task TestBehavior()
+        {
+            var s = new SemaphoreWrapper(1);
+            Assert.Equal(1, s.SpotsLeft);
+
+            await s.EnterQueue();
+            Assert.Equal(0, s.SpotsLeft);
+
+            s.LeaveQueue();
+            Assert.Equal(1, s.SpotsLeft);
+        }
+
+        [Fact]
+        public void TestQueueLength()
+        {
+            var s = new SemaphoreWrapper(2);
+
+            var t1 = s.EnterQueue();
+            Assert.True(t1.IsCompleted);
+
+            var t2 = s.EnterQueue();
+            Assert.True(t2.IsCompleted);
+
+            var t3 = s.EnterQueue();
+            Assert.False(t3.IsCompleted);
+        }
+
+        [Fact]
+        public async Task TestWaiting()
+        {
+            var s = new SemaphoreWrapper(1);
+            await s.EnterQueue();
+
+            var waitingTask = s.EnterQueue();
+            Assert.False(waitingTask.IsCompleted);
+
+            s.LeaveQueue();
+            await waitingTask.TimeoutAfter(TimeSpan.FromSeconds(1));
+        }
+    }
+}

src/Middleware/build.cmd

@@ -0,0 +1,3 @@
+@ECHO OFF
+SET RepoRoot=%~dp0..\..
+%RepoRoot%\build.cmd -projects %~dp0\**\*.*proj %*