#23 - Implement graceful shutdown.

src/Microsoft.AspNet.Hosting/ApplicationLifetime.cs

@@ -0,0 +1,72 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Threading;
+
+namespace Microsoft.AspNet.Hosting
+{
+    /// <summary>
+    /// Allows consumers to perform cleanup during a graceful shutdown.
+    /// </summary>
+    public class ApplicationLifetime : IApplicationLifetime
+    {
+        private readonly CancellationTokenSource _stoppingSource = new CancellationTokenSource();
+        private readonly CancellationTokenSource _stoppedSource = new CancellationTokenSource();
+
+        public ApplicationLifetime()
+        {
+        }
+
+        /// <summary>
+        /// Triggered when the application host is performing a graceful shutdown.
+        /// Request may still be in flight. Shutdown will block until this event completes.
+        /// </summary>
+        /// <returns></returns>
+        public CancellationToken ApplicationStopping
+        {
+            get { return _stoppingSource.Token; }
+        }
+
+        /// <summary>
+        /// Triggered when the application host is performing a graceful shutdown.
+        /// All requests should be complete at this point. Shutdown will block
+        /// until this event completes.
+        /// </summary>
+        /// <returns></returns>
+        public CancellationToken ApplicationStopped
+        {
+            get { return _stoppedSource.Token; }
+        }
+
+        /// <summary>
+        /// Signals the ApplicationStopping event and blocks until it completes.
+        /// </summary>
+        public void SignalStopping()
+        {
+            try
+            {
+                _stoppingSource.Cancel(throwOnFirstException: false);
+            }
+            catch (Exception)
+            {
+                // TODO: LOG
+            }
+        }
+
+        /// <summary>
+        /// Signals the ApplicationStopped event and blocks until it completes.
+        /// </summary>
+        public void SignalStopped()
+        {
+            try
+            {
+                _stoppedSource.Cancel(throwOnFirstException: false);
+            }
+            catch (Exception)
+            {
+                // TODO: LOG
+            }
+        }
+    }
+}

src/Microsoft.AspNet.Hosting/HostingContext.cs

@@ -27,6 +27,7 @@ namespace Microsoft.AspNet.Hosting
     {
         public IServiceProvider Services { get; set; }
         public IConfiguration Configuration { get; set; }
+        public ApplicationLifetime Lifetime { get; set; }
 
         public IBuilder Builder { get; set; }
 

src/Microsoft.AspNet.Hosting/HostingEngine.cs

@@ -21,6 +21,7 @@ using Microsoft.AspNet.Hosting.Builder;
 using Microsoft.AspNet.Hosting.Server;
 using Microsoft.AspNet.Hosting.Startup;
 using Microsoft.Framework.DependencyInjection;
+using Microsoft.Framework.DependencyInjection.Fallback;
 
 namespace Microsoft.AspNet.Hosting
 {
@@ -45,6 +46,7 @@ namespace Microsoft.AspNet.Hosting
 
         public IDisposable Start(HostingContext context)
         {
+            EnsureLifetime(context);
             EnsureBuilder(context);
             EnsureServerFactory(context);
             InitalizeServerFactory(context);
@@ -55,11 +57,24 @@ namespace Microsoft.AspNet.Hosting
            
             return new Disposable(() =>
             {
+                context.Lifetime.SignalStopping();
                 server.Dispose();
+                context.Lifetime.SignalStopped();
                 pipeline.Dispose();
             });
         }
 
+        private void EnsureLifetime(HostingContext context)
+        {
+            if (context.Lifetime == null)
+            {
+                context.Lifetime = new ApplicationLifetime();
+            }
+            var serviceCollection = new ServiceCollection();
+            serviceCollection.AddInstance<IApplicationLifetime>(context.Lifetime);
+            context.Services = serviceCollection.BuildServiceProvider(context.Services);
+        }
+
         private void EnsureBuilder(HostingContext context)
         {
             if (context.Builder != null)

src/Microsoft.AspNet.Hosting/IApplicationLifetime.cs

@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Threading;
+using Microsoft.Framework.Runtime;
+
+namespace Microsoft.AspNet.Hosting
+{
+    /// <summary>
+    /// Allows consumers to perform cleanup during a graceful shutdown.
+    /// </summary>
+    [AssemblyNeutral]
+    public interface IApplicationLifetime
+    {
+        /// <summary>
+        /// Triggered when the application host is performing a graceful shutdown.
+        /// Request may still be in flight. Shutdown will block until this event completes.
+        /// </summary>
+        /// <returns></returns>
+        CancellationToken ApplicationStopping { get; }
+
+        /// <summary>
+        /// Triggered when the application host is performing a graceful shutdown.
+        /// All requests should be complete at this point. Shutdown will block
+        /// until this event completes.
+        /// </summary>
+        /// <returns></returns>
+        CancellationToken ApplicationStopped { get; }
+    }
+}

src/Microsoft.AspNet.Hosting/Microsoft.AspNet.Hosting.kproj

@@ -20,6 +20,7 @@
     <Content Include="project.json" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="ApplicationLifetime.cs" />
     <Compile Include="Builder\BuilderFactory.cs" />
     <Compile Include="Builder\HttpContextFactory.cs" />
     <Compile Include="Builder\IBuilderFactory.cs" />
@@ -27,6 +28,7 @@
     <Compile Include="HostingContext.cs" />
     <Compile Include="HostingEngine.cs" />
     <Compile Include="HostingServices.cs" />
+    <Compile Include="IApplicationLifetime.cs" />
     <Compile Include="IHostingEngine.cs" />
     <Compile Include="PipelineInstance.cs" />
     <Compile Include="PlatformHelper.cs" />

src/Microsoft.AspNet.Hosting/Program.cs

@@ -17,6 +17,8 @@
 
 using System;
 using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
 using Microsoft.Framework.ConfigurationModel;
 using Microsoft.Framework.DependencyInjection;
 using Microsoft.Framework.DependencyInjection.Fallback;
@@ -67,11 +69,29 @@ namespace Microsoft.AspNet.Hosting
                 throw new Exception("TODO: IHostingEngine service not available exception");
             }
 
-            using (engine.Start(context))
+            var appShutdownService = _serviceProvider.GetService<IApplicationShutdown>();
+            if (appShutdownService == null)
+            {
+                throw new Exception("TODO: IApplicationShutdown service not available");
+            }
+            var shutdownHandle = new ManualResetEvent(false);
+
+            var serverShutdown = engine.Start(context);
+
+            appShutdownService.ShutdownRequested.Register(() =>
+            {
+                serverShutdown.Dispose();
+                shutdownHandle.Set();
+            });
+
+            Task ignored = Task.Run(() =>
             {
                 Console.WriteLine("Started");
                 Console.ReadLine();
-            }
+                appShutdownService.RequestShutdown();
+            });
+
+            shutdownHandle.WaitOne();
         }
     }
 }