From 2c1376c95ff46b0870d323ee5c5b064af263062e Mon Sep 17 00:00:00 2001
From: "Chris Ross (ASP.NET)" <chrross@microsoft.com>
Date: Tue, 1 May 2018 11:06:25 -0700
Subject: [PATCH] Add a AddHostedService extension #1402

---
 .../ProgramExternallyControlled.cs            |  4 ++--
 .../GenericHostSample/ProgramFullControl.cs   |  4 ++--
 .../GenericHostSample/ProgramHelloWorld.cs    |  4 ++--
 .../ServiceBaseControlled.cs                  |  4 ++--
 samples/GenericWebHost/WebHostExtensions.cs   |  2 +-
 ...erviceCollectionHostedServiceExtensions.cs | 20 +++++++++++++++++++
 .../WebHostTests.cs                           |  2 +-
 .../HostTests.cs                              |  4 ++--
 8 files changed, 32 insertions(+), 12 deletions(-)
 create mode 100644 src/Microsoft.Extensions.Hosting.Abstractions/ServiceCollectionHostedServiceExtensions.cs

diff --git a/samples/GenericHostSample/ProgramExternallyControlled.cs b/samples/GenericHostSample/ProgramExternallyControlled.cs
index 749442b161..7691b73ef2 100644
--- a/samples/GenericHostSample/ProgramExternallyControlled.cs
+++ b/samples/GenericHostSample/ProgramExternallyControlled.cs
@@ -25,8 +25,8 @@ namespace GenericHostSample
                 })
                 .ConfigureServices((hostContext, services) =>
                 {
-                    services.AddScoped<IHostedService, MyServiceA>();
-                    services.AddScoped<IHostedService, MyServiceB>();
+                    services.AddHostedService<MyServiceA>();
+                    services.AddHostedService<MyServiceB>();
                 })
                 .Build();
         }
diff --git a/samples/GenericHostSample/ProgramFullControl.cs b/samples/GenericHostSample/ProgramFullControl.cs
index 59400077bb..e94477e003 100644
--- a/samples/GenericHostSample/ProgramFullControl.cs
+++ b/samples/GenericHostSample/ProgramFullControl.cs
@@ -23,8 +23,8 @@ namespace GenericHostSample
                 })
                 .ConfigureServices((hostContext, services) =>
                 {
-                    services.AddScoped<IHostedService, MyServiceA>();
-                    services.AddScoped<IHostedService, MyServiceB>();
+                    services.AddHostedService<MyServiceA>();
+                    services.AddHostedService<MyServiceB>();
                 })
                 .Build();
 
diff --git a/samples/GenericHostSample/ProgramHelloWorld.cs b/samples/GenericHostSample/ProgramHelloWorld.cs
index a145a2534d..3145c40773 100644
--- a/samples/GenericHostSample/ProgramHelloWorld.cs
+++ b/samples/GenericHostSample/ProgramHelloWorld.cs
@@ -11,8 +11,8 @@ namespace GenericHostSample
             var builder = new HostBuilder()
                 .ConfigureServices((hostContext, services) =>
                 {
-                    services.AddScoped<IHostedService, MyServiceA>();
-                    services.AddScoped<IHostedService, MyServiceB>();
+                    services.AddHostedService<MyServiceA>();
+                    services.AddHostedService<MyServiceB>();
                 });
 
             await builder.RunConsoleAsync();
diff --git a/samples/GenericHostSample/ServiceBaseControlled.cs b/samples/GenericHostSample/ServiceBaseControlled.cs
index 431e061be5..24f63f992d 100644
--- a/samples/GenericHostSample/ServiceBaseControlled.cs
+++ b/samples/GenericHostSample/ServiceBaseControlled.cs
@@ -12,8 +12,8 @@ namespace GenericHostSample
             var builder = new HostBuilder()
                 .ConfigureServices((hostContext, services) =>
                 {
-                    services.AddScoped<IHostedService, MyServiceA>();
-                    services.AddScoped<IHostedService, MyServiceB>();
+                    services.AddHostedService<MyServiceA>();
+                    services.AddHostedService<MyServiceB>();
                 });
 
             await builder.RunAsServiceAsync();
diff --git a/samples/GenericWebHost/WebHostExtensions.cs b/samples/GenericWebHost/WebHostExtensions.cs
index 2226aba233..bf5567d81a 100644
--- a/samples/GenericWebHost/WebHostExtensions.cs
+++ b/samples/GenericWebHost/WebHostExtensions.cs
@@ -22,7 +22,7 @@ namespace GenericWebHost
                 {
                     options.ConfigureApp = configureApp;
                 });
-                services.AddSingleton<IHostedService, WebHostService>();
+                services.AddHostedService<WebHostService>();
                 
                 var listener = new DiagnosticListener("Microsoft.AspNetCore");
                 services.AddSingleton<DiagnosticListener>(listener);
diff --git a/src/Microsoft.Extensions.Hosting.Abstractions/ServiceCollectionHostedServiceExtensions.cs b/src/Microsoft.Extensions.Hosting.Abstractions/ServiceCollectionHostedServiceExtensions.cs
new file mode 100644
index 0000000000..98bdbd333a
--- /dev/null
+++ b/src/Microsoft.Extensions.Hosting.Abstractions/ServiceCollectionHostedServiceExtensions.cs
@@ -0,0 +1,20 @@
+// 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.Extensions.Hosting;
+
+namespace Microsoft.Extensions.DependencyInjection
+{
+    public static class ServiceCollectionHostedServiceExtensions
+    {
+        /// <summary>
+        /// Add an <see cref="IHostedService"/> registration for the given type.
+        /// </summary>
+        /// <typeparam name="THostedService">An <see cref="IHostedService"/> to register.</typeparam>
+        /// <param name="services">The <see cref="IServiceCollection"/> to register with.</param>
+        /// <returns>The original <see cref="IServiceCollection"/>.</returns>
+        public static IServiceCollection AddHostedService<THostedService>(this IServiceCollection services)
+            where THostedService : class, IHostedService
+            => services.AddTransient<IHostedService, THostedService>();
+    }
+}
diff --git a/test/Microsoft.AspNetCore.Hosting.Tests/WebHostTests.cs b/test/Microsoft.AspNetCore.Hosting.Tests/WebHostTests.cs
index 373836e5ea..0bc568277c 100644
--- a/test/Microsoft.AspNetCore.Hosting.Tests/WebHostTests.cs
+++ b/test/Microsoft.AspNetCore.Hosting.Tests/WebHostTests.cs
@@ -548,7 +548,7 @@ namespace Microsoft.AspNetCore.Hosting
                    .UseFakeServer()
                    .ConfigureServices(services =>
                    {
-                       services.AddSingleton<IHostedService, TestHostedService>();
+                       services.AddHostedService<TestHostedService>();
                    })
                    .Build())
             {
diff --git a/test/Microsoft.Extensions.Hosting.Tests/HostTests.cs b/test/Microsoft.Extensions.Hosting.Tests/HostTests.cs
index 5f6b5db76e..31a38b81c5 100644
--- a/test/Microsoft.Extensions.Hosting.Tests/HostTests.cs
+++ b/test/Microsoft.Extensions.Hosting.Tests/HostTests.cs
@@ -110,7 +110,7 @@ namespace Microsoft.Extensions.Hosting
             using (var host = CreateBuilder()
                    .ConfigureServices((hostContext, services) =>
                    {
-                       services.AddSingleton<IHostedService, TestHostedService>();
+                       services.AddHostedService<TestHostedService>();
                    })
                    .Build())
             {
@@ -133,7 +133,7 @@ namespace Microsoft.Extensions.Hosting
             using (var host = CreateBuilder()
                    .ConfigureServices((hostContext, services) =>
                    {
-                       services.AddSingleton<IHostedService, TestHostedService>();
+                       services.AddHostedService<TestHostedService>();
                    })
                    .Build())
             {