candoumbe/Extensions.Hosting.AsyncInitialization

Async initialization in .NET Core generic host (.NET Core 2.1+ and ASP.NET Core 3)

Extensions.Hosting.AsyncInitialization

A simple helper to perform async application initialization for the generic host in .NET Core 2.1 or higher (including ASP.NET Core 3).

Note: ASP.NET Core 2.x doesn't use the generic host. If you need to perform async initialization in ASP.NET Core 2.x, use AspNetCore.AsyncInitialization instead.

Usage

1. Install the Extensions.Hosting.AsyncInitialization NuGet package:

   Command line:

   dotnet add package Extensions.Hosting.AsyncInitialization

   Package manager console:

   Install-Package Extensions.Hosting.AsyncInitialization

2. Create a class (or several) that implements IAsyncInitializer. This class can depend on any registered service.

   public class MyAppInitializer : IAsyncInitializer
   {
       public MyAppInitializer(IFoo foo, IBar bar)
       {
           ...
       }
   
       public async Task InitializeAsync()
       {
           // Initialization code here
       }
   }

3. Register your initializer(s) in the same place as other services:

       services.AddAsyncInitializer<MyAppInitializer>();

4. In the Program class, make the Main method async and change its code to initialize the host before running it:

   public static async Task Main(string[] args)
   {
       var host = CreateHostBuilder(args).Build();
       await host.InitAsync();
       await host.RunAsync();
   }

(Note that you need to set the C# language version to 7.1 or higher in your project to enable the "async Main" feature.)

This will run each initializer, in the order in which they were registered.