'Unable to resolve service for type 'Microsoft.Extensions.Logging.ILogger`1[Application.Startup]' while attempting to activate 'Application.Startup'.'

Question

I have an ASP.NET Core 3.0 application. I am getting error as

I Know that ILogger is not default registered in ASP.NET Core 3.0 Application. Below is my code for Program.cs and Startup.cs for reference

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureLogging(logging =>
          {
            logging.ClearProviders();
            logging.SetMinimumLevel(LogLevel.Trace);
          })
        .ConfigureWebHostDefaults(webBuilder =>
        {
          webBuilder.UseStartup();
        });

Startup.cs

public void ConfigureServices(IServiceCollection services)
    {
        var serviceProvider = services.BuildServiceProvider();
        var logger = serviceProvider.GetService>();
        services.AddSingleton(typeof(ILogger), logger);
        ...
     }

Please can anyone help me with this error, What I am doing wrong in my case ?

user_10955627 · Answer

As per https://docs.microsoft.com/en-us/aspnet/core/fundamentals/logging/?view=aspnetcore-3.1#create-logs-in-the-startup-class writing logs before completion of the DI container setup in the Startup.ConfigureServices method is not supported.

You cannot do var logger = serviceProvider.GetService>(); since the DI container is not configured yet, at that stage.

'Unable to resolve service for type 'Microsoft.Extensions.Logging.ILogger`1[Application.Startup]' while attempting to activate 'Application.Startup'.'

1 Answers