c# - Using a Scoped service in a Singleton in an Asp.Net Core app

Question

In my Asp.Net Core App I need a singleton service that I can reuse for the lifetime of the application. To construct it, I need a DbContext (from the EF Core), but it is a scoped service and not thread safe.

Therefore I am using the following pattern to construct my singleton service. It looks kinda hacky, therefore I was wondering whether this is an acceptable approach and won't lead to any problems?

services.AddScoped<IPersistedConfigurationDbContext, PersistedConfigurationDbContext>();
services.AddSingleton<IPersistedConfigurationService>(s =>
{
    ConfigModel currentConfig;
    using (var scope = s.CreateScope())
    {
        var dbContext = scope.ServiceProvider.GetRequiredService<IPersistedConfigurationDbContext>();
        currentConfig = dbContext.retrieveConfig();            
    }
    return new PersistedConfigurationService(currentConfig);
});

...

public class ConfigModel
{
    string configParam { get; set; }
}

Answer 1

Although Dependency injection: Service lifetimes documentation in ASP.NET Core says:

It's dangerous to resolve a scoped service from a singleton. It may cause the service to have incorrect state when processing subsequent requests.

But in your case this is not the issue. Actually you are not resolving the scoped service from singleton. Its just getting an instance of scoped service from singleton whenever it requires. So your code should work properly without any disposed context error!

But another potential solution can be using IHostedService. Here is the details about it:

Consuming a scoped service in a background task (IHostedService)