我已经在asp.net核心网站中实现了IHostedService。它运作良好,但问题是我希望在托管服务器启动或IIS服务重新启动时启动它,但除非有第一个对网站的请求进入,否则它不会启动。
UPDATE 1:@Arthur建议的“应用程序初始化模块”没有帮助。既不在站点级别,也不在服务器级别。
我使用的配置:
<applicationInitialization
doAppInitAfterRestart="true"
skipManagedModules="false"
remapManagedRequestsTo="init.htm">
<add initializationPage="/init.htm" hostName="localhost"/>
</applicationInitialization>
UPDATE 2:这是我实现接口的方式
internal class PaymentQueueService : IHostedService, IDisposable
{
private readonly ILogger _logService;
private Timer _timerEnqueue;
public PaymentQueueService(ILogger logService)
{
_logService = logService;
}
public Task StartAsync(CancellationToken cancellationToken)
{
_logService.LogInformation("Starting processing payments.");
_timerEnqueue = new Timer(EnqueuePayments, null, TimeSpan.Zero,
TimeSpan.FromSeconds(10));
return Task.CompletedTask;
}
private void EnqueuePayments(object state)
{
_logService.LogInformation("Enqueueing Payments.");
}
public Task StopAsync(CancellationToken cancellationToken)
{
_logService.LogInformation("Stopping processing payments.");
_timerEnqueue?.Change(Timeout.Infinite, 0);
return Task.CompletedTask;
}
public void Dispose()
{
_timerEnqueue?.Dispose();
}
}
main.cs文件中的Program类:
public class Program
{
public static void Main(string[] args)
{
CreateWebHostBuilder(args).Build().Run();
}
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args).ConfigureServices(services =>
{
services.AddHostedService<PaymentQueueService>();
}).Configure((IApplicationBuilder app) =>
{
app.UseMvc();
})
.UseStartup<Startup>();
}
启动类:
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostEnvironment env)
{
}
}
由于建议的“应用程序初始化模块”不起作用,因此您可以考虑与客户端进行通话
当第一个请求到达时,模块启动ASP.NET Core应用程序的进程,如果关闭或崩溃,则重新启动应用程序。
public class Program {
static Lazy<HttpClient> client = new Lazy<HttpClient>();
public static async Task Main(string[] args) {
var host = CreateWebHostBuilder(args).Start();//non blocking start
using (host) {
bool started = false;
do {
var response = await client.Value.GetAsync("site root");
started = response.IsSuccessStatusCode;
await Task.Delay(someDelayHere);
} while (!started);
host.WaitForShutdown();
}
}
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.ConfigureServices(services => {
services.AddHostedService<PaymentQueueService>();
})
.Configure((IApplicationBuilder app) => {
app.UseMvc();
})
.UseStartup<Startup>();
}
NOTE:
为了防止托管进程外的应用程序超时,请使用以下两种方法之一:
- 通过外部服务对应用程序执行Ping操作,以使其保持运行状态。
- 如果该应用仅托管后台服务,请避免IIS托管,而使用Windows Service托管ASP.NET Core应用。