Merge branch 'release/2.1' into dev

samples/GenericHostSample/ServiceBaseLifetime.cs

@@ -23,23 +23,35 @@ namespace GenericHostSample
 
     public class ServiceBaseLifetime : ServiceBase, IHostLifetime
     {
-        private Action<object> _startCallback;
+        private TaskCompletionSource<object> _delayStart = new TaskCompletionSource<object>();
-        private Action<object> _stopCallback;
-        private object _startState;
-        private object _stopState;
 
-        public void RegisterDelayStartCallback(Action<object> callback, object state)
+        public ServiceBaseLifetime(IApplicationLifetime applicationLifetime)
         {
-            _startCallback = callback ?? throw new ArgumentNullException(nameof(callback));
+            ApplicationLifetime = applicationLifetime ?? throw new ArgumentNullException(nameof(applicationLifetime));
-            _startState = state;
-
-            Run(this);
         }
 
-        public void RegisterStopCallback(Action<object> callback, object state)
+        private IApplicationLifetime ApplicationLifetime { get; }
+
+        public Task WaitForStartAsync(CancellationToken cancellationToken)
         {
-            _stopCallback = callback ?? throw new ArgumentNullException(nameof(callback));
+            cancellationToken.Register(() => _delayStart.TrySetCanceled());
-            _stopState = state;
+            ApplicationLifetime.ApplicationStopping.Register(Stop);
+
+            new Thread(Run).Start(); // Otherwise this would block and prevent IHost.StartAsync from finishing.
+            return _delayStart.Task;
+        }
+
+        private void Run()
+        {
+            try
+            {
+                Run(this); // This blocks until the service is stopped.
+                _delayStart.TrySetException(new InvalidOperationException("Stopped without starting"));
+            }
+            catch (Exception ex)
+            {
+                _delayStart.TrySetException(ex);
+            }
         }
 
         public Task StopAsync(CancellationToken cancellationToken)
@@ -48,15 +60,18 @@ namespace GenericHostSample
             return Task.CompletedTask;
         }
 
+        // Called by base.Run when the service is ready to start.
         protected override void OnStart(string[] args)
         {
-            _startCallback(_startState);
+            _delayStart.TrySetResult(null);
             base.OnStart(args);
         }
 
+        // Called by base.Stop. This may be called multiple times by service Stop, ApplicationStopping, and StopAsync.
+        // That's OK because StopApplication uses a CancellationTokenSource and prevents any recursion.
         protected override void OnStop()
         {
-            _stopCallback(_stopState);
+            ApplicationLifetime.StopApplication();
             base.OnStop();
         }
     }

src/Microsoft.Extensions.Hosting.Abstractions/IHostLifetime.cs

@@ -1,7 +1,6 @@
 // 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 System;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -10,20 +9,10 @@ namespace Microsoft.Extensions.Hosting
     public interface IHostLifetime
     {
         /// <summary>
-        /// Called at the start of <see cref="IHost.StartAsync(CancellationToken)"/> which will wait until the callback is invoked before
+        /// Called at the start of <see cref="IHost.StartAsync(CancellationToken)"/> which will wait until it's compete before
         /// continuing. This can be used to delay startup until signaled by an external event.
         /// </summary>
-        /// <param name="callback">A callback that will be invoked when the host should continue.</param>
+        Task WaitForStartAsync(CancellationToken cancellationToken);
-        /// <param name="state">State to pass to the callback.</param>
-        void RegisterDelayStartCallback(Action<object> callback, object state);
-
-        /// <summary>
-        /// Called at the start of <see cref="IHost.StartAsync(CancellationToken)"/> to register the given callback for initiating the
-        /// application shutdown process.
-        /// </summary>
-        /// <param name="callback">A callback to invoke when an external signal indicates the application should stop.</param>
-        /// <param name="state">State to pass to the callback.</param>
-        void RegisterStopCallback(Action<object> callback, object state);
 
         /// <summary>
         /// Called from <see cref="IHost.StopAsync(CancellationToken)"/> to indicate that the host as stopped and clean up resources.

src/Microsoft.Extensions.Hosting/HostBuilder.cs

@@ -178,7 +178,7 @@ namespace Microsoft.Extensions.Hosting
             services.AddSingleton(_hostBuilderContext);
             services.AddSingleton(_appConfiguration);
             services.AddSingleton<IApplicationLifetime, ApplicationLifetime>();
-            services.AddSingleton<IHostLifetime, ProcessLifetime>();
+            services.AddSingleton<IHostLifetime, ConsoleLifetime>();
             services.AddSingleton<IHost, Host>();
             services.AddOptions();
             services.AddLogging();

src/Microsoft.Extensions.Hosting/Internal/ConsoleLifetime.cs

@@ -26,7 +26,7 @@ namespace Microsoft.Extensions.Hosting.Internal
 
         private IApplicationLifetime ApplicationLifetime { get; }
 
-        public void RegisterDelayStartCallback(Action<object> callback, object state)
+        public Task WaitForStartAsync(CancellationToken cancellationToken)
         {
             if (!Options.SuppressStatusMessages)
             {
@@ -38,18 +38,15 @@ namespace Microsoft.Extensions.Hosting.Internal
                 });
             }
 
-            // Console applications start immediately.
+            AppDomain.CurrentDomain.ProcessExit += (sender, eventArgs) => ApplicationLifetime.StopApplication();
-            callback(state);
-        }
-
-        public void RegisterStopCallback(Action<object> callback, object state)
-        {
-            AppDomain.CurrentDomain.ProcessExit += (sender, eventArgs) => callback(state);
             Console.CancelKeyPress += (sender, e) =>
             {
                 e.Cancel = true;
-                callback(state);
+                ApplicationLifetime.StopApplication();
             };
+
+            // Console applications start immediately.
+            return Task.CompletedTask;
         }
 
         public Task StopAsync(CancellationToken cancellationToken)

src/Microsoft.Extensions.Hosting/Internal/Host.cs

@@ -36,13 +36,9 @@ namespace Microsoft.Extensions.Hosting.Internal
         {
             _logger.Starting();
 
-            var delayStart = new TaskCompletionSource<object>();
+            await _hostLifetime.WaitForStartAsync(cancellationToken);
-            cancellationToken.Register(obj => ((TaskCompletionSource<object>)obj).TrySetCanceled(), delayStart);
-            _hostLifetime.RegisterDelayStartCallback(obj => ((TaskCompletionSource<object>)obj).TrySetResult(null), delayStart);
-            _hostLifetime.RegisterStopCallback(obj => (obj as IApplicationLifetime)?.StopApplication(), _applicationLifetime);
-
-            await delayStart.Task;
 
+            cancellationToken.ThrowIfCancellationRequested();
             _hostedServices = Services.GetService<IEnumerable<IHostedService>>();
 
             foreach (var hostedService in _hostedServices)

src/Microsoft.Extensions.Hosting/Internal/ProcessLifetime.cs

@@ -1,28 +0,0 @@
-// 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 System;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace Microsoft.Extensions.Hosting.Internal
-{
-    public class ProcessLifetime : IHostLifetime
-    {
-        public void RegisterDelayStartCallback(Action<object> callback, object state)
-        {
-            // Never delays start.
-            callback(state);
-        }
-
-        public void RegisterStopCallback(Action<object> callback, object state)
-        {
-            AppDomain.CurrentDomain.ProcessExit += (sender, eventArgs) => callback(state);
-        }
-
-        public Task StopAsync(CancellationToken cancellationToken)
-        {
-            return Task.CompletedTask;
-        }
-    }
-}

test/Microsoft.Extensions.Hosting.Tests/Fakes/FakeHostLifetime.cs

@@ -10,23 +10,16 @@ namespace Microsoft.Extensions.Hosting.Tests.Fakes
     public class FakeHostLifetime : IHostLifetime
     {
         public int StartCount { get; internal set; }
-        public int StoppingCount { get; internal set; }
         public int StopCount { get; internal set; }
 
-        public Action<Action<object>, object> StartAction { get; set; }
+        public Action<CancellationToken> StartAction { get; set; }
-        public Action<Action<object>, object> StoppingAction { get; set; }
         public Action StopAction { get; set; }
         
-        public void RegisterDelayStartCallback(Action<object> callback, object state)
+        public Task WaitForStartAsync(CancellationToken cancellationToken)
         {
             StartCount++;
-            StartAction?.Invoke(callback, state);
+            StartAction?.Invoke(cancellationToken);
-        }
+            return Task.CompletedTask;
-
-        public void RegisterStopCallback(Action<object> callback, object state)
-        {
-            StoppingCount++;
-            StoppingAction?.Invoke(callback, state);
         }
 
         public Task StopAsync(CancellationToken cancellationToken)

test/Microsoft.Extensions.Hosting.Tests/HostTests.cs

@@ -233,11 +233,10 @@ namespace Microsoft.Extensions.Hosting
                     });
                     services.AddSingleton<IHostLifetime>(_ => new FakeHostLifetime()
                     {
-                        StartAction = (callback, state) =>
+                        StartAction = ct =>
                         {
                             lifetimeStart.Set();
                             Assert.True(lifetimeContinue.WaitOne(TimeSpan.FromSeconds(5)));
-                            callback(state);
                         }
                     });
                 })
@@ -259,7 +258,6 @@ namespace Microsoft.Extensions.Hosting
 
                 lifetime = (FakeHostLifetime)host.Services.GetRequiredService<IHostLifetime>();
                 Assert.Equal(1, lifetime.StartCount);
-                Assert.Equal(1, lifetime.StoppingCount);
                 Assert.Equal(0, lifetime.StopCount);
             }
 
@@ -268,7 +266,6 @@ namespace Microsoft.Extensions.Hosting
             Assert.Equal(1, service.DisposeCount);
 
             Assert.Equal(1, lifetime.StartCount);
-            Assert.Equal(1, lifetime.StoppingCount);
             Assert.Equal(0, lifetime.StopCount);
         }
 
@@ -292,9 +289,10 @@ namespace Microsoft.Extensions.Hosting
                     });
                     services.AddSingleton<IHostLifetime>(_ => new FakeHostLifetime()
                     {
-                        StartAction = (callback, state) =>
+                        StartAction = ct =>
                         {
                             lifetimeStart.Set();
+                            WaitHandle.WaitAny(new[] { lifetimeContinue, ct.WaitHandle });
                         }
                     });
                 })
@@ -308,7 +306,7 @@ namespace Microsoft.Extensions.Hosting
                 Assert.False(serviceStarting.WaitOne(0));
 
                 cts.Cancel();
-                await Assert.ThrowsAsync<TaskCanceledException>(() => startTask);
+                await Assert.ThrowsAsync<OperationCanceledException>(() => startTask);
                 Assert.False(serviceStarting.WaitOne(0));
 
                 lifetimeContinue.Set();
@@ -322,7 +320,6 @@ namespace Microsoft.Extensions.Hosting
 
                 lifetime = (FakeHostLifetime)host.Services.GetRequiredService<IHostLifetime>();
                 Assert.Equal(1, lifetime.StartCount);
-                Assert.Equal(1, lifetime.StoppingCount);
                 Assert.Equal(0, lifetime.StopCount);
             }
 
@@ -331,61 +328,6 @@ namespace Microsoft.Extensions.Hosting
             Assert.Equal(1, service.DisposeCount);
 
             Assert.Equal(1, lifetime.StartCount);
-            Assert.Equal(1, lifetime.StoppingCount);
-            Assert.Equal(0, lifetime.StopCount);
-        }
-
-        [Fact]
-        public async Task HostLifetimeOnStoppingTriggersIApplicationLifetime()
-        {
-            var lifetimeRegistered = new ManualResetEvent(false);
-            Action<object> stoppingAction = null;
-            object stoppingState = null;
-            FakeHostedService service;
-            FakeHostLifetime lifetime;
-            using (var host = CreateBuilder()
-                .ConfigureServices((services) =>
-                {
-                    services.AddSingleton<IHostedService, FakeHostedService>();
-                    services.AddSingleton<IHostLifetime>(_ => new FakeHostLifetime()
-                    {
-                        StartAction = (callback, state) => callback(state),
-                        StoppingAction = (callback, state) =>
-                        {
-                            stoppingAction = callback;
-                            stoppingState = state;
-                            lifetimeRegistered.Set();
-                        }
-                    });
-                })
-                .Build())
-            {
-                await host.StartAsync();
-                Assert.True(lifetimeRegistered.WaitOne(0));
-
-                var appLifetime = host.Services.GetRequiredService<IApplicationLifetime>();
-
-                stoppingAction(stoppingState);
-
-                Assert.True(appLifetime.ApplicationStopping.WaitHandle.WaitOne(TimeSpan.FromSeconds(5)));
-
-                service = (FakeHostedService)host.Services.GetRequiredService<IHostedService>();
-                Assert.Equal(1, service.StartCount);
-                Assert.Equal(0, service.StopCount);
-                Assert.Equal(0, service.DisposeCount);
-
-                lifetime = (FakeHostLifetime)host.Services.GetRequiredService<IHostLifetime>();
-                Assert.Equal(1, lifetime.StartCount);
-                Assert.Equal(1, lifetime.StoppingCount);
-                Assert.Equal(0, lifetime.StopCount);
-            }
-
-            Assert.Equal(1, service.StartCount);
-            Assert.Equal(0, service.StopCount);
-            Assert.Equal(1, service.DisposeCount);
-
-            Assert.Equal(1, lifetime.StartCount);
-            Assert.Equal(1, lifetime.StoppingCount);
             Assert.Equal(0, lifetime.StopCount);
         }
 
@@ -398,10 +340,7 @@ namespace Microsoft.Extensions.Hosting
                 .ConfigureServices((services) =>
                 {
                     services.AddSingleton<IHostedService, FakeHostedService>();
-                    services.AddSingleton<IHostLifetime>(_ => new FakeHostLifetime()
+                    services.AddSingleton<IHostLifetime, FakeHostLifetime>();
-                    {
-                        StartAction = (callback, state) => callback(state),
-                    });
                 })
                 .Build())
             {
@@ -414,7 +353,6 @@ namespace Microsoft.Extensions.Hosting
 
                 lifetime = (FakeHostLifetime)host.Services.GetRequiredService<IHostLifetime>();
                 Assert.Equal(1, lifetime.StartCount);
-                Assert.Equal(1, lifetime.StoppingCount);
                 Assert.Equal(0, lifetime.StopCount);
 
                 await host.StopAsync();
@@ -424,7 +362,6 @@ namespace Microsoft.Extensions.Hosting
                 Assert.Equal(0, service.DisposeCount);
 
                 Assert.Equal(1, lifetime.StartCount);
-                Assert.Equal(1, lifetime.StoppingCount);
                 Assert.Equal(1, lifetime.StopCount);
             }
 
@@ -433,7 +370,6 @@ namespace Microsoft.Extensions.Hosting
             Assert.Equal(1, service.DisposeCount);
 
             Assert.Equal(1, lifetime.StartCount);
-            Assert.Equal(1, lifetime.StoppingCount);
             Assert.Equal(1, lifetime.StopCount);
         }