Execute IHostingStart instances in the primary assembly (#1033)

* #1000 Execute IHostingStart instances in the primary assembly
Also make the sample app runnable.
Add an opt-out flag, more tests

Hosting.sln

@@ -1,7 +1,6 @@
-
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.26228.4
+VisualStudioVersion = 15.0.26418.1
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{E0497F39-AFFB-4819-A116-E39E361915AB}"
 EndProject
@@ -31,6 +30,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.AspNetCore.Hostin
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.AspNetCore.Hosting.TestSites", "test\Microsoft.AspNetCore.Hosting.TestSites\Microsoft.AspNetCore.Hosting.TestSites.csproj", "{542D4600-B232-4B17-A08C-E31EBFA0D74E}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "TestStartupAssembly1", "test\TestStartupAssembly1\TestStartupAssembly1.csproj", "{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -165,6 +166,18 @@ Global
 		{542D4600-B232-4B17-A08C-E31EBFA0D74E}.Release|Mixed Platforms.Build.0 = Release|Any CPU
 		{542D4600-B232-4B17-A08C-E31EBFA0D74E}.Release|x86.ActiveCfg = Release|Any CPU
 		{542D4600-B232-4B17-A08C-E31EBFA0D74E}.Release|x86.Build.0 = Release|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Debug|x86.Build.0 = Debug|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Release|Any CPU.Build.0 = Release|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Release|x86.ActiveCfg = Release|Any CPU
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -181,5 +194,6 @@ Global
 		{03148731-EA95-40A2-BAE8-A12315EA1748} = {E0497F39-AFFB-4819-A116-E39E361915AB}
 		{FC578F4E-171C-4F82-B301-3ABF6318D082} = {FEB39027-9158-4DE2-997F-7ADAEF8188D0}
 		{542D4600-B232-4B17-A08C-E31EBFA0D74E} = {FEB39027-9158-4DE2-997F-7ADAEF8188D0}
+		{39D3B138-37DB-4D03-A5A0-3F2B02EFC671} = {FEB39027-9158-4DE2-997F-7ADAEF8188D0}
 	EndGlobalSection
 EndGlobal

build/repo.props

@@ -1,5 +1,6 @@
 <Project>
   <ItemGroup>
     <ExcludeFromTest Include="$(RepositoryRoot)test\Microsoft.AspNetCore.Hosting.TestSites\Microsoft.AspNetCore.Hosting.TestSites.csproj" />
+    <ExcludeFromTest Include="$(RepositoryRoot)test\TestStartupAssembly1\TestStartupAssembly1.csproj" />
   </ItemGroup>
 </Project>

samples/SampleStartups/FakeServer.cs

@@ -0,0 +1,32 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Hosting.Server;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace SampleStartups
+{
+    // We can't reference real servers in this sample without creating a circular repo dependency.
+    // This fake server lets us at least run the code.
+    public class FakeServer : IServer
+    {
+        public IFeatureCollection Features => new FeatureCollection();
+
+        public Task StartAsync<TContext>(IHttpApplication<TContext> application, CancellationToken cancellationToken) => Task.CompletedTask;
+
+        public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
+
+        public void Dispose()
+        {
+        }
+    }
+
+    public static class FakeServerWebHostBuliderExtensions
+    {
+        public static IWebHostBuilder UseFakeServer(this IWebHostBuilder builder)
+        {
+            return builder.ConfigureServices(services => services.AddSingleton<IServer, FakeServer>());
+        }
+    }
+}

samples/SampleStartups/SampleStartups.csproj

@@ -4,6 +4,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>net46;netcoreapp2.0</TargetFrameworks>
+    <StartupObject>SampleStartups.StartupInjection</StartupObject>
+    <OutputType>exe</OutputType>
   </PropertyGroup>
 
   <ItemGroup>

samples/SampleStartups/StartupBlockingOnStart.cs

@@ -34,6 +34,7 @@ namespace SampleStartups
 
             var host = new WebHostBuilder()
                 .UseConfiguration(config)
+                .UseFakeServer()
                 .UseStartup<StartupBlockingOnStart>()
                 .Build();
 

samples/SampleStartups/StartupConfigureAddresses.cs

@@ -25,6 +25,7 @@ namespace SampleStartups
 
             var host = new WebHostBuilder()
                 .UseConfiguration(config)
+                .UseFakeServer()
                 .UseStartup<StartupConfigureAddresses>()
                 .UseUrls("http://localhost:5000", "http://localhost:5001")
                 .Build();

samples/SampleStartups/StartupExternallyControlled.cs

@@ -32,6 +32,7 @@ namespace SampleStartups
         {
             _host = new WebHostBuilder()
                 //.UseKestrel()
+                .UseFakeServer()
                 .UseStartup<StartupExternallyControlled>()
                 .Start(_urls.ToArray());
         }

samples/SampleStartups/StartupFullControl.cs

@@ -22,7 +22,8 @@ namespace SampleStartups
 
             var host = new WebHostBuilder()
                 .UseConfiguration(config) // Default set of configurations to use, may be subsequently overridden 
-              //.UseKestrel()
+                //.UseKestrel()
+                .UseFakeServer()
                 .UseContentRoot(Directory.GetCurrentDirectory()) // Override the content root with the current directory
                 .UseUrls("http://*:1000", "https://*:902")
                 .UseEnvironment("Development")

samples/SampleStartups/StartupHelloWorld.cs

@@ -21,7 +21,8 @@ namespace SampleStartups
         public static void Main(string[] args)
         {
             var host = new WebHostBuilder()
-              //.UseKestrel()
+                //.UseKestrel()
+                .UseFakeServer()
                 .UseStartup<StartupHelloWorld>()
                 .Build();
 

samples/SampleStartups/StartupInjection.cs

@@ -0,0 +1,69 @@
+using System;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+
+// HostingStartup's in the primary assembly are run automatically.
+[assembly: HostingStartup(typeof(SampleStartups.StartupInjection))]
+
+namespace SampleStartups
+{
+    public class StartupInjection : IHostingStartup
+    {
+        public void Configure(IWebHostBuilder builder)
+        {
+            builder.UseStartup<InjectedStartup>();
+        }
+
+        // Entry point for the application.
+        public static void Main(string[] args)
+        {
+            var host = new WebHostBuilder()
+                //.UseKestrel()
+                .UseFakeServer()
+                // Each of these three sets ApplicationName to the current assembly, which is needed in order to
+                // scan the assembly for HostingStartupAttributes.
+                // .UseSetting(WebHostDefaults.ApplicationKey, "SampleStartups")
+                // .Configure(_ => { })
+                .UseStartup<NormalStartup>()
+                .Build();
+
+            host.Run();
+        }
+    }
+
+    public class NormalStartup
+    {
+        public void ConfigureServices(IServiceCollection services)
+        {
+            Console.WriteLine("NormalStartup.ConfigureServices");
+        }
+
+        public void Configure(IApplicationBuilder app)
+        {
+            Console.WriteLine("NormalStartup.Configure");
+            app.Run(async (context) =>
+            {
+                await context.Response.WriteAsync("Hello World!");
+            });
+        }
+    }
+
+    public class InjectedStartup
+    {
+        public void ConfigureServices(IServiceCollection services)
+        {
+            Console.WriteLine("InjectedStartup.ConfigureServices");
+        }
+
+        public void Configure(IApplicationBuilder app)
+        {
+            Console.WriteLine("InjectedStartup.Configure");
+            app.Run(async (context) =>
+            {
+                await context.Response.WriteAsync("Hello World!");
+            });
+        }
+    }
+}

src/Microsoft.AspNetCore.Hosting.Abstractions/WebHostDefaults.cs

@@ -16,6 +16,7 @@ namespace Microsoft.AspNetCore.Hosting
         public static readonly string ServerUrlsKey = "urls";
         public static readonly string ContentRootKey = "contentRoot";
         public static readonly string PreferHostingUrlsKey = "preferHostingUrls";
+        public static readonly string PreventHostingStartupKey = "preventHostingStartup";
 
         public static readonly string ShutdownTimeoutKey = "shutdownTimeoutSeconds";
     }

src/Microsoft.AspNetCore.Hosting/Internal/WebHostOptions.cs

@@ -26,7 +26,10 @@ namespace Microsoft.AspNetCore.Hosting.Internal
             Environment = configuration[WebHostDefaults.EnvironmentKey];
             WebRoot = configuration[WebHostDefaults.WebRootKey];
             ContentRootPath = configuration[WebHostDefaults.ContentRootKey];
-            HostingStartupAssemblies = configuration[WebHostDefaults.HostingStartupAssembliesKey]?.Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries) ?? new string[0];
+            PreventHostingStartup = ParseBool(configuration, WebHostDefaults.PreventHostingStartupKey);
+            // Search the primary assembly and configured assemblies.
+            HostingStartupAssemblies = $"{ApplicationName};{configuration[WebHostDefaults.HostingStartupAssembliesKey]}"
+                .Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries) ?? new string[0];
             PreferHostingUrls = ParseBool(configuration, WebHostDefaults.PreferHostingUrlsKey);
 
             var timeout = configuration[WebHostDefaults.ShutdownTimeoutKey];
@@ -39,6 +42,8 @@ namespace Microsoft.AspNetCore.Hosting.Internal
 
         public string ApplicationName { get; set; }
 
+        public bool PreventHostingStartup { get; set; }
+
         public IReadOnlyList<string> HostingStartupAssemblies { get; set; }
 
         public bool DetailedErrors { get; set; }

src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs

@@ -302,36 +302,39 @@ namespace Microsoft.AspNetCore.Hosting
             services.AddSingleton(loggerFactory);
             _context.LoggerFactory = loggerFactory;
 
-            var exceptions = new List<Exception>();
+            if (!_options.PreventHostingStartup)
-
-            // Execute the hosting startup assemblies
-            foreach (var assemblyName in _options.HostingStartupAssemblies)
             {
-                try
+                var exceptions = new List<Exception>();
-                {
-                    var assembly = Assembly.Load(new AssemblyName(assemblyName));
 
-                    foreach (var attribute in assembly.GetCustomAttributes<HostingStartupAttribute>())
+                // Execute the hosting startup assemblies
+                foreach (var assemblyName in _options.HostingStartupAssemblies)
+                {
+                    try
                     {
-                        var hostingStartup = (IHostingStartup)Activator.CreateInstance(attribute.HostingStartupType);
+                        var assembly = Assembly.Load(new AssemblyName(assemblyName));
-                        hostingStartup.Configure(this);
+
+                        foreach (var attribute in assembly.GetCustomAttributes<HostingStartupAttribute>())
+                        {
+                            var hostingStartup = (IHostingStartup)Activator.CreateInstance(attribute.HostingStartupType);
+                            hostingStartup.Configure(this);
+                        }
+                    }
+                    catch (Exception ex)
+                    {
+                        // Capture any errors that happen during startup
+                        exceptions.Add(new InvalidOperationException($"Startup assembly {assemblyName} failed to execute. See the inner exception for more details.", ex));
                     }
                 }
-                catch (Exception ex)
-                {
-                    // Capture any errors that happen during startup
-                    exceptions.Add(new InvalidOperationException($"Startup assembly {assemblyName} failed to execute. See the inner exception for more details.", ex));
-                }
-            }
 
-            if (exceptions.Count > 0)
+                if (exceptions.Count > 0)
-            {
-                hostingStartupErrors = new AggregateException(exceptions);
-
-                // Throw directly if we're not capturing startup errors
-                if (!_options.CaptureStartupErrors)
                 {
-                    throw hostingStartupErrors;
+                    hostingStartupErrors = new AggregateException(exceptions);
+
+                    // Throw directly if we're not capturing startup errors
+                    if (!_options.CaptureStartupErrors)
+                    {
+                        throw hostingStartupErrors;
+                    }
                 }
             }
 

test/Microsoft.AspNetCore.Hosting.Tests/Microsoft.AspNetCore.Hosting.Tests.csproj

@@ -13,6 +13,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Microsoft.AspNetCore.Hosting\Microsoft.AspNetCore.Hosting.csproj" />
+    <ProjectReference Include="..\TestStartupAssembly1\TestStartupAssembly1.csproj" />
   </ItemGroup>
 
   <ItemGroup>

test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs

@@ -833,13 +833,30 @@ namespace Microsoft.AspNetCore.Hosting
         {
             var builder = CreateWebHostBuilder()
                 .CaptureStartupErrors(false)
-                .UseSetting(WebHostDefaults.HostingStartupAssembliesKey, typeof(WebHostBuilderTests).GetTypeInfo().Assembly.FullName)
+                .UseSetting(WebHostDefaults.HostingStartupAssembliesKey, typeof(TestStartupAssembly1.TestHostingStartup1).GetTypeInfo().Assembly.FullName)
                 .Configure(app => { })
                 .UseServer(new TestServer());
 
             using (var host = builder.Build())
             {
-                Assert.Equal("1", builder.GetSetting("testhostingstartup"));
+                Assert.Equal("1", builder.GetSetting("testhostingstartup1"));
+            }
+        }
+
+        [Fact]
+        public void Build_RunsHostingStartupRunsPrimaryAssemblyFirst()
+        {
+            var builder = CreateWebHostBuilder()
+                .CaptureStartupErrors(false)
+                .UseSetting(WebHostDefaults.HostingStartupAssembliesKey, typeof(TestStartupAssembly1.TestHostingStartup1).GetTypeInfo().Assembly.FullName)
+                .Configure(app => { })
+                .UseServer(new TestServer());
+
+            using (var host = builder.Build())
+            {
+                Assert.Equal("0", builder.GetSetting("testhostingstartup"));
+                Assert.Equal("1", builder.GetSetting("testhostingstartup1"));
+                Assert.Equal("01", builder.GetSetting("testhostingstartup_chain"));
             }
         }
 
@@ -871,7 +888,6 @@ namespace Microsoft.AspNetCore.Hosting
         {
             var builder = CreateWebHostBuilder()
                 .CaptureStartupErrors(false)
-                .UseSetting(WebHostDefaults.HostingStartupAssembliesKey, typeof(WebHostBuilderTests).GetTypeInfo().Assembly.FullName)
                 .Configure(app =>
                 {
                     var loggerFactory = app.ApplicationServices.GetService<ILoggerFactory>();
@@ -888,12 +904,26 @@ namespace Microsoft.AspNetCore.Hosting
         }
 
         [Fact]
-        public void Build_DoesNotRunHostingStartupAssembliesDoNotRunIfNotSpecified()
+        public void Build_DoesRunHostingStartupFromPrimaryAssemblyEvenIfNotSpecified()
         {
             var builder = CreateWebHostBuilder()
                 .Configure(app => { })
                 .UseServer(new TestServer());
 
+            using (builder.Build())
+            {
+                Assert.Equal("0", builder.GetSetting("testhostingstartup"));
+            }
+        }
+
+        [Fact]
+        public void Build_HostingStartupFromPrimaryAssemblyCanBeDisabled()
+        {
+            var builder = CreateWebHostBuilder()
+                .UseSetting(WebHostDefaults.PreventHostingStartupKey, "true")
+                .Configure(app => { })
+                .UseServer(new TestServer());
+
             using (builder.Build())
             {
                 Assert.Null(builder.GetSetting("testhostingstartup"));
@@ -1027,7 +1057,8 @@ namespace Microsoft.AspNetCore.Hosting
             public void Configure(IWebHostBuilder builder)
             {
                 var loggerProvider = new TestLoggerProvider();
-                builder.UseSetting("testhostingstartup", "1")
+                builder.UseSetting("testhostingstartup", "0")
+                       .UseSetting("testhostingstartup_chain", builder.GetSetting("testhostingstartup_chain") + "0")
                        .ConfigureServices(services => services.AddSingleton<ServiceA>())
                        .ConfigureServices(services => services.AddSingleton<ITestSink>(loggerProvider.Sink))
                        .ConfigureLogging(lf => lf.AddProvider(loggerProvider));

test/TestStartupAssembly1/TestHostingStartup1.cs

@@ -0,0 +1,18 @@
+// 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 Microsoft.AspNetCore.Hosting;
+
+[assembly: HostingStartup(typeof(TestStartupAssembly1.TestHostingStartup1))]
+
+namespace TestStartupAssembly1
+{
+    public class TestHostingStartup1 : IHostingStartup
+    {
+        public void Configure(IWebHostBuilder builder)
+        {
+            builder.UseSetting("testhostingstartup1", "1");
+            builder.UseSetting("testhostingstartup_chain", builder.GetSetting("testhostingstartup_chain") + "1");
+        }
+    }
+}

test/TestStartupAssembly1/TestStartupAssembly1.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <Import Project="..\..\build\common.props" />
+  
+  <PropertyGroup>
+    <TargetFrameworks>netcoreapp2.0;net46</TargetFrameworks>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Microsoft.AspNetCore.Hosting.Abstractions\Microsoft.AspNetCore.Hosting.Abstractions.csproj" />
+  </ItemGroup>
+
+</Project>