.NET Core 2.1中的通用主机正常关闭 [英] Graceful shutdown with Generic Host in .NET Core 2.1
问题描述
.NET Core 2.1引入了新的通用主机，该主机可以承载非HTTP工作负载以及Web主机的所有优点。当前，没有太多的信息和食谱，但是我以以下文章作为起点：
.NET Core 2.1 introduced new Generic Host, which allows to host non-HTTP workloads with all benefits of Web Host. Currently, there is no much information and recipes with it, but I used following articles as a starting point:
https://docs.microsoft.com/zh-CN/aspnet/core/fundamentals/ host / generic-host？view = aspnetcore-2.1
https://docs.microsoft.com/zh-cn/aspnet/core/fundamentals/host/hosted-services?view = aspnetcore-2.1
我的.NET Core ap复制开始，通过RabbitMQ消息代理侦听新请求，并根据用户请求（通常通过控制台中的Ctrl + C）关闭。但是，关机并不是正常的-应用程序在将控制权返回给OS时仍具有未完成的后台线程。我通过控制台消息看到它-当我在控制台中按Ctrl + C时，我从应用程序中看到几行控制台输出，然后是OS命令提示符，然后又从应用程序中再次看到控制台输出。
My .NET Core application starts, listens for new requests via RabbitMQ message broker and shuts down by user request (usually by Ctrl+C in console). However, shutdown is not graceful - application still have unfinished background threads while it returns control to OS. I see it by console messages - when I press Ctrl+C in console I see few lines of console output from my application, then OS command prompt and then again console output from my application.
这是我的代码：
Program.cs
public class Program
{
public static async Task Main(string[] args)
{
var host = new HostBuilder()
.ConfigureHostConfiguration(config =>
{
config.SetBasePath(AppContext.BaseDirectory);
config.AddEnvironmentVariables(prefix: "ASPNETCORE_");
config.AddJsonFile("hostsettings.json", optional: true);
})
.ConfigureAppConfiguration((context, config) =>
{
var env = context.HostingEnvironment;
config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);
config.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true);
if (env.IsProduction())
config.AddDockerSecrets();
config.AddEnvironmentVariables();
})
.ConfigureServices((context, services) =>
{
services.AddLogging();
services.AddHostedService<WorkerPoolHostedService>();
// ... other services
})
.ConfigureLogging((context, logging) =>
{
if (context.HostingEnvironment.IsDevelopment())
logging.AddDebug();
logging.AddSerilog(dispose: true);
Log.Logger = new LoggerConfiguration()
.ReadFrom.Configuration(context.Configuration)
.CreateLogger();
})
.UseConsoleLifetime()
.Build();
await host.RunAsync();
}
}
WorkerPoolHostedService.cs
internal class WorkerPoolHostedService : IHostedService
{
private IList<VideoProcessingWorker> _workers;
private CancellationTokenSource _stoppingCts = new CancellationTokenSource();
protected WorkerPoolConfiguration WorkerPoolConfiguration { get; }
protected RabbitMqConfiguration RabbitMqConfiguration { get; }
protected IServiceProvider ServiceProvider { get; }
protected ILogger<WorkerPoolHostedService> Logger { get; }
public WorkerPoolHostedService(
IConfiguration configuration,
IServiceProvider serviceProvider,
ILogger<WorkerPoolHostedService> logger)
{
this.WorkerPoolConfiguration = new WorkerPoolConfiguration(configuration);
this.RabbitMqConfiguration = new RabbitMqConfiguration(configuration);
this.ServiceProvider = serviceProvider;
this.Logger = logger;
}
public async Task StartAsync(CancellationToken cancellationToken)
{
var connectionFactory = new ConnectionFactory
{
AutomaticRecoveryEnabled = true,
UserName = this.RabbitMqConfiguration.Username,
Password = this.RabbitMqConfiguration.Password,
HostName = this.RabbitMqConfiguration.Hostname,
Port = this.RabbitMqConfiguration.Port,
VirtualHost = this.RabbitMqConfiguration.VirtualHost
};
_workers = Enumerable.Range(0, this.WorkerPoolConfiguration.WorkerCount)
.Select(i => new VideoProcessingWorker(
connectionFactory: connectionFactory,
serviceScopeFactory: this.ServiceProvider.GetRequiredService<IServiceScopeFactory>(),
logger: this.ServiceProvider.GetRequiredService<ILogger<VideoProcessingWorker>>(),
cancellationToken: _stoppingCts.Token))
.ToList();
this.Logger.LogInformation("Worker pool started with {0} workers.", this.WorkerPoolConfiguration.WorkerCount);
}
public async Task StopAsync(CancellationToken cancellationToken)
{
this.Logger.LogInformation("Stopping working pool...");
try
{
_stoppingCts.Cancel();
await Task.WhenAll(_workers.SelectMany(w => w.ActiveTasks).ToArray());
}
catch (AggregateException ae)
{
ae.Handle((Exception exc) =>
{
this.Logger.LogError(exc, "Error while cancelling workers");
return true;
});
}
finally
{
if (_workers != null)
{
foreach (var worker in _workers)
worker.Dispose();
_workers = null;
}
}
}
}
VideoProcessingWorker.cs
internal class VideoProcessingWorker : IDisposable
{
private readonly Guid _id = Guid.NewGuid();
private bool _disposed = false;
protected IConnection Connection { get; }
protected IModel Channel { get; }
protected IServiceScopeFactory ServiceScopeFactory { get; }
protected ILogger<VideoProcessingWorker> Logger { get; }
protected CancellationToken CancellationToken { get; }
public VideoProcessingWorker(
IConnectionFactory connectionFactory,
IServiceScopeFactory serviceScopeFactory,
ILogger<VideoProcessingWorker> logger,
CancellationToken cancellationToken)
{
this.Connection = connectionFactory.CreateConnection();
this.Channel = this.Connection.CreateModel();
this.Channel.BasicQos(prefetchSize: 0, prefetchCount: 1, global: false);
this.ServiceScopeFactory = serviceScopeFactory;
this.Logger = logger;
this.CancellationToken = cancellationToken;
#region [ Declare ]
// ...
#endregion
#region [ Consume ]
// ...
#endregion
}
// ... worker logic ...
public void Dispose()
{
if (!_disposed)
{
this.Channel.Close(200, "Goodbye");
this.Channel.Dispose();
this.Connection.Close();
this.Connection.Dispose();
this.Logger.LogDebug("Worker {0}: disposed.", _id);
}
_disposed = true;
}
}
因此，当我按Ctrl + CI时，会看到以下输出在控制台中（没有请求处理时）：
So, when I press Ctrl+C I see following output in console (when there is no request processing):
停止工作池...
命令提示
工人 id ：已处置。
如何关闭
推荐答案
您需要 IApplicationLifetime 。这为您提供了有关应用程序启动和关闭的所有必需信息。您甚至可以通过 appLifetime.StopApplication（）;
You need IApplicationLifetime. This provides you with all the needed information about application start and shutdown. You can even trigger the shutdown with it via appLifetime.StopApplication();
代码段（如果链接无效）：
Snippet(if the link becomes invalid):
public Task StartAsync(CancellationToken cancellationToken)
{
appLifetime.ApplicationStarted.Register(OnStarted);
appLifetime.ApplicationStopping.Register(OnStopping);
appLifetime.ApplicationStopped.Register(OnStopped);
return Task.CompletedTask;
}
这篇关于.NET Core 2.1中的通用主机正常关闭的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
