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Review feedback for IApplicationLifetimeEvents 

- Renamed the type to IHostedService and added Start and Stop.
- Split up the IHostedService execution and IApplicationLifetime to avoid
circular references
- Trigger IHostedService.Start after starting the server
- Trigger IHostedService.Stop before disposing the service provider

#895 #894
This commit is contained in:
David Fowler 2016-12-05 23:13:50 -08:00
parent 73a0401362
commit c6346cbde5
6 changed files with 206 additions and 75 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
src/Microsoft.AspNetCore.Hosting.Abstractions/IApplicationLifetimeEvents.cs → src/Microsoft.AspNetCore.Hosting.Abstractions/IHostedService.cs
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@ -4,28 +4,20 @@
namespace Microsoft.AspNetCore.Hosting
{
/// <summary>
/// Allows consumers to perform cleanup during a graceful shutdown.
/// Defines methods for objects that are managed by the host.
/// </summary>
public interface IApplicationLifetimeEvents
public interface IHostedService
{
/// <summary>
/// Triggered when the application host has fully started and is about to wait
/// for a graceful shutdown.
/// Triggered when the application host has fully started and the server is waiting
/// for requests.
/// </summary>
void OnApplicationStarted();
void Start();
/// <summary>
/// Triggered when the application host is performing a graceful shutdown.
/// Requests may still be in flight. Shutdown will block until this event completes.
/// </summary>
void OnApplicationStopping();
/// <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>
void OnApplicationStopped();
void Stop();
}
}

30
src/Microsoft.AspNetCore.Hosting/Internal/ApplicationLifetime.cs
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@ -17,13 +17,11 @@ namespace Microsoft.AspNetCore.Hosting.Internal
private readonly CancellationTokenSource _startedSource = new CancellationTokenSource();
private readonly CancellationTokenSource _stoppingSource = new CancellationTokenSource();
private readonly CancellationTokenSource _stoppedSource = new CancellationTokenSource();
private readonly IEnumerable<IApplicationLifetimeEvents> _handlers = Enumerable.Empty<IApplicationLifetimeEvents>();
private readonly ILogger<ApplicationLifetime> _logger;
public ApplicationLifetime(ILogger<ApplicationLifetime> logger, IEnumerable<IApplicationLifetimeEvents> handlers)
public ApplicationLifetime(ILogger<ApplicationLifetime> logger)
{
_logger = logger;
_handlers = handlers;
}
/// <summary>
@ -57,7 +55,7 @@ namespace Microsoft.AspNetCore.Hosting.Internal
{
try
{
ExecuteHandlers(_stoppingSource, handler => handler.OnApplicationStopping());
ExecuteHandlers(_stoppingSource);
}
catch (Exception ex)
{
@ -75,7 +73,7 @@ namespace Microsoft.AspNetCore.Hosting.Internal
{
try
{
ExecuteHandlers(_startedSource, handler => handler.OnApplicationStarted());
ExecuteHandlers(_startedSource);
}
catch (Exception ex)
{
@ -92,7 +90,7 @@ namespace Microsoft.AspNetCore.Hosting.Internal
{
try
{
ExecuteHandlers(_stoppedSource, handler => handler.OnApplicationStopped());
ExecuteHandlers(_stoppedSource);
}
catch (Exception ex)
{
@ -102,7 +100,7 @@ namespace Microsoft.AspNetCore.Hosting.Internal
}
}
private void ExecuteHandlers(CancellationTokenSource cancel, Action<IApplicationLifetimeEvents> callback)
private void ExecuteHandlers(CancellationTokenSource cancel)
{
// Noop if this is already cancelled
if (cancel.IsCancellationRequested)
@ -127,24 +125,6 @@ namespace Microsoft.AspNetCore.Hosting.Internal
exceptions.Add(ex);
}
// Run the handlers
foreach (var handler in _handlers)
{
try
{
callback(handler);
}
catch (Exception ex)
{
if (exceptions == null)
{
exceptions = new List<Exception>();
}
exceptions.Add(ex);
}
}
// Throw an aggregate exception if there were any exceptions
if (exceptions != null)
{

70
src/Microsoft.AspNetCore.Hosting/Internal/HostedServiceExecutor.cs Normal file
View File

@ -0,0 +1,70 @@
using System;
using System.Collections.Generic;
using Microsoft.Extensions.Logging;
namespace Microsoft.AspNetCore.Hosting.Internal
{
public class HostedServiceExecutor
{
private readonly IEnumerable<IHostedService> _services;
private readonly ILogger<HostedServiceExecutor> _logger;
public HostedServiceExecutor(ILogger<HostedServiceExecutor> logger, IEnumerable<IHostedService> services)
{
_logger = logger;
_services = services;
}
public void Start()
{
try
{
Execute(service => service.Start());
}
catch (Exception ex)
{
_logger.ApplicationError(LoggerEventIds.HostedServiceStartException, "An error occurred starting the application", ex);
}
}
public void Stop()
{
try
{
Execute(service => service.Stop());
}
catch (Exception ex)
{
_logger.ApplicationError(LoggerEventIds.HostedServiceStopException, "An error occurred stopping the application", ex);
}
}
private void Execute(Action<IHostedService> callback)
{
List<Exception> exceptions = null;
foreach (var service in _services)
{
try
{
callback(service);
}
catch (Exception ex)
{
if (exceptions == null)
{
exceptions = new List<Exception>();
}
exceptions.Add(ex);
}
}
// Throw an aggregate exception if there were any exceptions
if (exceptions != null)
{
throw new AggregateException(exceptions);
}
}
}
}

2
src/Microsoft.AspNetCore.Hosting/Internal/LoggerEventIds.cs
View File

@ -13,5 +13,7 @@ namespace Microsoft.AspNetCore.Hosting.Internal
public const int ApplicationStartupException = 6;
public const int ApplicationStoppingException = 7;
public const int ApplicationStoppedException = 8;
public const int HostedServiceStartException = 9;
public const int HostedServiceStopException = 10;
}
}

16
src/Microsoft.AspNetCore.Hosting/Internal/WebHost.cs
View File

@ -28,6 +28,7 @@ namespace Microsoft.AspNetCore.Hosting.Internal
private readonly IServiceCollection _applicationServiceCollection;
private IStartup _startup;
private ApplicationLifetime _applicationLifetime;
private HostedServiceExecutor _hostedServiceExecutor;
private readonly IServiceProvider _hostingServiceProvider;
private readonly WebHostOptions _options;
@ -68,6 +69,7 @@ namespace Microsoft.AspNetCore.Hosting.Internal
_applicationServiceCollection = appServices;
_hostingServiceProvider = hostingServiceProvider;
_applicationServiceCollection.AddSingleton<IApplicationLifetime, ApplicationLifetime>();
_applicationServiceCollection.AddSingleton<HostedServiceExecutor>();
}
public IServiceProvider Services
@ -104,11 +106,17 @@ namespace Microsoft.AspNetCore.Hosting.Internal
Initialize();
_applicationLifetime = _applicationServices.GetRequiredService<IApplicationLifetime>() as ApplicationLifetime;
_hostedServiceExecutor = _applicationServices.GetRequiredService<HostedServiceExecutor>();
var diagnosticSource = _applicationServices.GetRequiredService<DiagnosticSource>();
var httpContextFactory = _applicationServices.GetRequiredService<IHttpContextFactory>();
Server.Start(new HostingApplication(_application, _logger, diagnosticSource, httpContextFactory));
// Fire IApplicationLifetime.Started
_applicationLifetime?.NotifyStarted();
// Fire IHostedService.Start
_hostedServiceExecutor.Start();
_logger.Started();
}
@ -243,9 +251,17 @@ namespace Microsoft.AspNetCore.Hosting.Internal
public void Dispose()
{
_logger?.Shutdown();
// Fire IApplicationLifetime.Stopping
_applicationLifetime?.StopApplication();
// Fire the IHostedService.Stop
_hostedServiceExecutor?.Stop();
(_hostingServiceProvider as IDisposable)?.Dispose();
(_applicationServices as IDisposable)?.Dispose();
// Fire IApplicationLifetime.Stopped
_applicationLifetime?.NotifyStopped();
HostingEventSource.Log.HostStop();

143
test/Microsoft.AspNetCore.Hosting.Tests/WebHostTests.cs
View File

@ -316,16 +316,13 @@ namespace Microsoft.AspNetCore.Hosting
host.Dispose();
Assert.True(events1[1]);
Assert.True(events2[1]);
Assert.True(events1[2]);
Assert.True(events2[2]);
}
}
[Fact]
public void WebHostStopCallbacksDontMultipleTimes()
public void WebHostStopApplicationDoesNotFireStopOnHostedService()
{
var stoppingCalls = 0;
var stoppedCalls = 0;
var host = CreateBuilder()
.UseServer(this)
@ -340,31 +337,96 @@ namespace Microsoft.AspNetCore.Hosting
stoppingCalls++;
};
Action stopped = () =>
{
stoppedCalls++;
};
services.AddSingleton<IApplicationLifetimeEvents>(new DelegateLifetimeEvents(started, stopping, stopped));
services.AddSingleton<IHostedService>(new DelegateHostedService(started, stopping));
})
.Build();
var lifetime = host.Services.GetRequiredService<IApplicationLifetime>();
lifetime.StopApplication();
lifetime.StopApplication();
lifetime.StopApplication();
using (host)
{
host.Start();
host.Dispose();
Assert.Equal(1, stoppingCalls);
Assert.Equal(1, stoppedCalls);
Assert.Equal(0, stoppingCalls);
}
}
[Fact]
public void WebHostNotifiesAllIApplicationLifetimeEventsCallbacksAndIApplicationLifetimeCallbacksEvenIfTheyThrow()
public void HostedServiceCanInjectApplicationLifetime()
{
var host = CreateBuilder()
.UseServer(this)
.ConfigureServices(services =>
{
services.AddSingleton<IHostedService, TestHostedService>();
})
.Build();
var lifetime = host.Services.GetRequiredService<IApplicationLifetime>();
lifetime.StopApplication();
host.Start();
var svc = (TestHostedService)host.Services.GetRequiredService<IHostedService>();
Assert.True(svc.StartCalled);
host.Dispose();
Assert.True(svc.StopCalled);
}
[Fact]
public void HostedServiceStartNotCalledIfWebHostNotStarted()
{
var host = CreateBuilder()
.UseServer(this)
.ConfigureServices(services =>
{
services.AddSingleton<IHostedService, TestHostedService>();
})
.Build();
var lifetime = host.Services.GetRequiredService<IApplicationLifetime>();
lifetime.StopApplication();
var svc = (TestHostedService)host.Services.GetRequiredService<IHostedService>();
Assert.False(svc.StartCalled);
host.Dispose();
Assert.False(svc.StopCalled);
}
[Fact]
public void WebHostDisposeApplicationFiresStopOnHostedService()
{
var stoppingCalls = 0;
var startedCalls = 0;
var host = CreateBuilder()
.UseServer(this)
.ConfigureServices(services =>
{
Action started = () =>
{
startedCalls++;
};
Action stopping = () =>
{
stoppingCalls++;
};
services.AddSingleton<IHostedService>(new DelegateHostedService(started, stopping));
})
.Build();
var lifetime = host.Services.GetRequiredService<IApplicationLifetime>();
using (host)
{
host.Start();
host.Dispose();
Assert.Equal(1, startedCalls);
Assert.Equal(1, stoppingCalls);
}
}
[Fact]
public void WebHostNotifiesAllIApplicationLifetimeEventsCallbacksAndIHostedServicesEvenIfTheyThrow()
{
bool[] events1 = null;
bool[] events2 = null;
@ -381,7 +443,6 @@ namespace Microsoft.AspNetCore.Hosting
var started = RegisterCallbacksThatThrow(applicationLifetime.ApplicationStarted);
var stopping = RegisterCallbacksThatThrow(applicationLifetime.ApplicationStopping);
var stopped = RegisterCallbacksThatThrow(applicationLifetime.ApplicationStopped);
using (host)
{
@ -393,9 +454,6 @@ namespace Microsoft.AspNetCore.Hosting
Assert.True(events1[1]);
Assert.True(events2[1]);
Assert.True(stopping.All(s => s));
Assert.True(events1[2]);
Assert.True(events2[2]);
Assert.True(stopped.All(s => s));
}
}
@ -654,7 +712,7 @@ namespace Microsoft.AspNetCore.Hosting
private static bool[] RegisterCallbacksThatThrow(IServiceCollection services)
{
bool[] events = new bool[3];
bool[] events = new bool[2];
Action started = () =>
{
@ -668,13 +726,7 @@ namespace Microsoft.AspNetCore.Hosting
throw new InvalidOperationException();
};
Action stopped = () =>
{
events[2] = true;
throw new InvalidOperationException();
};
services.AddSingleton<IApplicationLifetimeEvents>(new DelegateLifetimeEvents(started, stopping, stopped));
services.AddSingleton<IHostedService>(new DelegateHostedService(started, stopping));
return events;
}
@ -722,24 +774,43 @@ namespace Microsoft.AspNetCore.Hosting
}
}
private class DelegateLifetimeEvents : IApplicationLifetimeEvents
private class TestHostedService : IHostedService
{
private readonly IApplicationLifetime _lifetime;
public TestHostedService(IApplicationLifetime lifetime)
{
_lifetime = lifetime;
}
public bool StartCalled { get; set; }
public bool StopCalled { get; set; }
public void Start()
{
StartCalled = true;
}
public void Stop()
{
StopCalled = true;
}
}
private class DelegateHostedService : IHostedService
{
private readonly Action _started;
private readonly Action _stopping;
private readonly Action _stopped;
public DelegateLifetimeEvents(Action started, Action stopping, Action stopped)
public DelegateHostedService(Action started, Action stopping)
{
_started = started;
_stopping = stopping;
_stopped = stopped;
}
public void OnApplicationStarted() => _started();
public void Start() => _started();
public void OnApplicationStopped() => _stopped();
public void OnApplicationStopping() => _stopping();
public void Stop() => _stopping();
}
private class StartInstance : IDisposable