Make IServer Start and Stop async

src/Microsoft.AspNetCore.Server.Kestrel.Core/KestrelServer.cs

@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Net;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting.Server;
@@ -29,6 +30,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
         private readonly ITransportFactory _transportFactory;
 
         private bool _isRunning;
+        private int _stopped;
         private Heartbeat _heartbeat;
 
         public KestrelServer(
@@ -67,7 +69,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
 
         private InternalKestrelServerOptions InternalOptions { get; }
 
-        public void Start<TContext>(IHttpApplication<TContext> application)
+        public async Task StartAsync<TContext>(IHttpApplication<TContext> application, CancellationToken cancellationToken)
         {
             try
             {
@@ -129,7 +131,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                     _logger.LogDebug($"No listening endpoints were configured. Binding to {Constants.DefaultServerAddress} by default.");
 
                     // "localhost" for both IPv4 and IPv6 can't be represented as an IPEndPoint.
-                    StartLocalhost(ServerAddress.FromUrl(Constants.DefaultServerAddress), serviceContext, application);
+                    await StartLocalhostAsync(ServerAddress.FromUrl(Constants.DefaultServerAddress), serviceContext, application, cancellationToken);
 
                     // If StartLocalhost doesn't throw, there is at least one listener.
                     // The port cannot change for "localhost".
@@ -174,7 +176,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                             if (string.Equals(parsedAddress.Host, "localhost", StringComparison.OrdinalIgnoreCase))
                             {
                                 // "localhost" for both IPv4 and IPv6 can't be represented as an IPEndPoint.
-                                StartLocalhost(parsedAddress, serviceContext, application);
+                                await StartLocalhostAsync(parsedAddress, serviceContext, application, cancellationToken);
 
                                 // If StartLocalhost doesn't throw, there is at least one listener.
                                 // The port cannot change for "localhost".
@@ -200,9 +202,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
 
                     try
                     {
-                        transport.BindAsync().Wait();
+                        await transport.BindAsync();
                     }
-                    catch (AggregateException ex) when (ex.InnerException is AddressInUseException)
+                    catch (AddressInUseException ex)
                     {
                         throw new IOException($"Failed to bind to address {endPoint}: address already in use.", ex);
                     }
@@ -219,8 +221,14 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
             }
         }
 
-        public void Dispose()
+        // Graceful shutdown if possible
+        public async Task StopAsync(CancellationToken cancellationToken)
         {
+            if (Interlocked.Exchange(ref _stopped, 1) == 1)
+            {
+                return;
+            }
+
             if (_transports != null)
             {
                 var tasks = new Task[_transports.Count];
@@ -228,19 +236,27 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                 {
                     tasks[i] = _transports[i].UnbindAsync();
                 }
-                Task.WaitAll(tasks);
+                await Task.WhenAll(tasks);
 
                 // TODO: Do transport-agnostic connection management/shutdown.
                 for (int i = 0; i < _transports.Count; i++)
                 {
                     tasks[i] = _transports[i].StopAsync();
                 }
-                Task.WaitAll(tasks);
+                await Task.WhenAll(tasks);
             }
 
             _heartbeat?.Dispose();
         }
 
+        // Ungraceful shutdown
+        public void Dispose()
+        {
+            var cancelledTokenSource = new CancellationTokenSource();
+            cancelledTokenSource.Cancel();
+            StopAsync(cancelledTokenSource.Token).GetAwaiter().GetResult();
+        }
+
         private void ValidateOptions()
         {
             if (Options.Limits.MaxRequestBufferSize.HasValue &&
@@ -258,7 +274,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
             }
         }
 
-        private void StartLocalhost<TContext>(ServerAddress parsedAddress, ServiceContext serviceContext, IHttpApplication<TContext> application)
+        private async Task StartLocalhostAsync<TContext>(ServerAddress parsedAddress, ServiceContext serviceContext, IHttpApplication<TContext> application, CancellationToken cancellationToken)
         {
             if (parsedAddress.Port == 0)
             {
@@ -277,16 +293,16 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                 var connectionHandler = new ConnectionHandler<TContext>(ipv4ListenOptions, serviceContext, application);
                 var transport = _transportFactory.Create(ipv4ListenOptions, connectionHandler);
                 _transports.Add(transport);
-                transport.BindAsync().Wait();
+                await transport.BindAsync();
             }
-            catch (AggregateException ex) when (ex.InnerException is AddressInUseException)
+            catch (AddressInUseException ex)
             {
                 throw new IOException($"Failed to bind to address {parsedAddress} on the IPv4 loopback interface: port already in use.", ex);
             }
-            catch (AggregateException ex)
+            catch (Exception ex)
             {
                 _logger.LogWarning(0, $"Unable to bind to {parsedAddress} on the IPv4 loopback interface: ({ex.Message})");
-                exceptions.Add(ex.InnerException);
+                exceptions.Add(ex);
             }
 
             try
@@ -299,16 +315,16 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                 var connectionHandler = new ConnectionHandler<TContext>(ipv6ListenOptions, serviceContext, application);
                 var transport = _transportFactory.Create(ipv6ListenOptions, connectionHandler);
                 _transports.Add(transport);
-                transport.BindAsync().Wait();
+                await transport.BindAsync();
             }
-            catch (AggregateException ex) when (ex.InnerException is AddressInUseException)
+            catch (AddressInUseException ex)
             {
                 throw new IOException($"Failed to bind to address {parsedAddress} on the IPv6 loopback interface: port already in use.", ex);
             }
-            catch (AggregateException ex)
+            catch (Exception ex)
             {
                 _logger.LogWarning(0, $"Unable to bind to {parsedAddress} on the IPv6 loopback interface: ({ex.Message})");
-                exceptions.Add(ex.InnerException);
+                exceptions.Add(ex);
             }
 
             if (exceptions.Count == 2)

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/KestrelServerTests.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Linq;
 using System.Net;
+using System.Threading;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting.Server;
 using Microsoft.AspNetCore.Hosting.Server.Features;
@@ -161,7 +162,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
         private static void StartDummyApplication(IServer server)
         {
-            server.Start(new DummyApplication(context => TaskCache.CompletedTask));
+            server.StartAsync(new DummyApplication(context => TaskCache.CompletedTask), CancellationToken.None).GetAwaiter().GetResult();
         }
 
         private class MockTransportFactory : ITransportFactory

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/TestHelpers/TimeoutTestServer.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Net;
+using System.Threading;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core;
 using Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv;
@@ -27,7 +28,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests.TestHelpers
 
             try
             {
-                _server.Start(new DummyApplication(app));
+                _server.StartAsync(new DummyApplication(app), CancellationToken.None).GetAwaiter().GetResult();
             }
             catch
             {