运行 ASP.Net 核心应用程序启动期间的异步代码

Question

将函数 ConfigureServices 的签名更改为异步后（最初它只是一个无效的同步函数，应用程序运行良好），我收到以下错误：

Unable to find the required services. Please add all the required services by calling IServiceCollection.AddAuthorization inside the call to ConfigureServices(...) in the application startup code.

下面是我的 ConfigureServices 函数的代码。

// This method gets called by the runtime. Use this method to add services to the container.
public async Task ConfigureServices(IServiceCollection services)
{
    services.AddRazorPages();

    // Create the necessary Cosmos DB infrastructure
    await CreateDatabaseAsync();
    await CreateContainerAsync();
}

ConfigureServices 在运行时自动调用。

Answer 1

签名不能随便改，需要为void才能被框架调用

现在当你把它改成Task的时候，就意味着框架找不到它，所以它根本不会被调用。

这里有一个 GitHub 问题：https://github.com/dotnet/aspnetcore/issues/5897

虽然这很棘手...

There's no progress for 5.0 no, we don't know how to do this without blocking or breaking changes. It might be possible to run filters in 2 stages that never overlap.

根据您的评论更新：如果你想在启动时运行一些异步的东西，我通常这样做：

我创建了一个这样的界面：

public interface IStartupTask
{
     Task Execute();
}

然后像这样的示例实现

public class CreateDatabaseStartupTask : IStartupTask
{
    public async Task Execute()
    {
          // My logic here
          // await CreateDatabaseAsync();
    }
}

然后在我的Program.cs

public static async Task Main(string[] args)
{
    var host = CreateHostBuilder(args).Build();
    
    // Resolve the StartupTasks from the ServiceProvider
    var startupTasks = host.Services.GetServices<IStartupTask>();
    
    // Run the StartupTasks
    foreach(var startupTask in startupTasks)
    {
        await startupTask.Execute();
    }
    await host.RunAsync();
}

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        });
}

还有我的创业公司

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddTransient<IStartupTask, CreateDatabaseStartupTask>();
    }
}

所以重要的事情是：

注册您的 StartupTasks
构建主机
解决 StartupTasks
运行启动任务
启动主机

运行 ASP.Net 核心应用程序启动期间的异步代码

Run async code during startup in a ASP.Net Core application

c#

asynchronous

azure

asp.net-core

azure-webapps