AddDbContext doesn't provide a LoggerFactory on the CoreOptionsExtension.

[qsdfplkj]

I want to use the LoggerFactory from the CoreOptionsExtension .

public class MyContext : DbContext
{
    private readonly ILogger<MyContext> logger;

    public MyContext(DbContextOptions options) : base(options)
    {
        logger = options.FindExtension<CoreOptionsExtension>()?.LoggerFactory?.CreateLogger<MyContext>();
        if (logger == null)
        {
            throw new Exception("Logger required.");
        }
    }
}

This will throw the exception:

services.AddDbContext<MyContext>();

This does work but then the documentation states:

//     There is no need to call this method when using one of the 'AddDbContext' methods,
//     including 'AddDbContextPool'. These methods ensure that the Microsoft.Extensions.Logging.ILoggerFactory
//     used by EF is obtained from the application service provider.

services.AddDbContext<MyContext>((serviceProvider, optionsBuilder) =>
{
    optionsBuilder.UseLoggerFactory(serviceProvider.GetService<ILoggerFactory>());
});

[ajcvickers]

@qsdfplkj The integration with ASP.NET logging doesn't set LoggerFactory on the context options. This will only be set if an application has explicitly configured a LoggerFactory. However, ASP.NET Core automatically registers the ILoggerFactory in the application service provider, so you should be able to resolve it directly in the DbContext constructor. For example:

public MyContext(DbContextOptions options, ILoggerFactory loggerFactory) : base(options)
{
    logger = loggerFactory.CreateLogger<MyContext>();
}

[qsdfplkj]

Ah, now I see it, it can either injected but the EF can resolve it via:

 options.FindExtension<CoreOptionsExtension>().ApplicationServiceProvider.GetService<ILoggerFactory>();. 

Use UseLoggerFactory to explicitly configure a LoggerFactory. (I was used to call UseLoggerFactory always).