How to fix obsolete ILoggerFactory methods?

I upgraded my project to .NET Core 2.2.x and got an obsolete warning regarding the following code - both lines:

public void Configure(IApplicationBuilder app, 
                      IHostingEnvironment env, 
                      ILoggerFactory loggerFactory) 
  {
    loggerFactory.AddConsole(Configuration.GetSection("Logging"));

The suggestion to fix is The recommended alternative is AddConsole(this ILoggingBuilder builder). I thought that is what I am using.

What am I missing here?

I had the same issue today.

Remove your logging configuration from Startup.cs and go to your Program.cs file and add something like:

var host = new WebHostBuilder()
    .UseKestrel()
    .UseContentRoot(Directory.GetCurrentDirectory())
    .UseIISIntegration()
    .UseStartup<Startup>()
    .ConfigureLogging((hostingContext, logging) =>
    {
        logging.AddConfiguration(hostingContext.Configuration.GetSection("Logging"));
        logging.AddConsole();
        logging.AddDebug();
    })
    .Build();

This used the 'builder' because the variable 'logging' is an IloggingBuilder (whereas your code is still using ILoggerFactory)

UPDATE: The other method I just tried is to stay inside Startup.cs but move the logging stuff from the 'Configure' method to 'ConfigureServices' like this:

public void ConfigureServices(IServiceCollection services)
{
    services.AddLogging(loggingBuilder =>
    {
        loggingBuilder.AddConfiguration(Configuration.GetSection("Logging"));
        loggingBuilder.AddConsole();
        loggingBuilder.AddDebug();
    });
}

Perhaps keeps the Program.cs less polluted...

The documentation's recommendation to use AddConsole(this ILoggingBuilder builder) is correct, but for that to work you need to add a reference to the NuGet package Microsoft.Extensions.Logging.Console.

I got the same warning when I was updating logging code from .Net Core 2.1 to 3.0. The recommended way to do the upgrade is documented on MSDN.

In my case, I was trying to get an instance of LoggerFactory for console which is pretty straightforward in .Net Core 3.0:

using (var loggerFactory = LoggerFactory.Create(builder => builder.AddConsole()))
{
    // use loggerFactory
}

Don't worry about it - this is the dumbest thing ever!

> Note > > The following code sample uses a ConsoleLoggerProvider constructor > that has been obsoleted in version 2.2. Proper replacements for > obsolete logging APIs will be available in version 3.0. In the > meantime, it is safe to ignore and suppress the warnings.

In case you thought you forgot what Obsolete meant - you hadn't! Don't worry about it and just ignore it for now - or suppress the warning (sorry I don't have the code for that to hand).

(Wish they'd put a better explanation for why this was done - that's what I mean by dumb.)

According to the issue opened on GitHub for this, the replacement methods are already being called if you use CreateDefaultBuilder() method in your Program.cs.

https://github.com/aspnet/Docs/issues/9829

The only issue I have is that I only turned these on for non-Production environments.. and don't see a way to do so going forward.

If you don't have access to the LoggerFactory.Create(), use can still use the ILoggerFactory with the AddProvider() method giving it a ConsoleLoggerProvider() but it is a bit of a pain if you want to do something simple. The problem is, ConsoleLoggerProvider() requires a IOptionsMonitor<ConsoleLoggerOptions> as a parameter and the easiest thing to do if you

• you don't have access to the options mechanism in your code base (my problem), or
• the real options mechanisms in your existing code base don't match up with IOptionsMonitor<>, or
• you have other reasons not to use the ASP.Net options facilities

is to create a dummy class:

using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Console;
using Microsoft.Extensions.Options;
	
	class DummyConsoleLoggerOptionsMonitor : IOptionsMonitor<ConsoleLoggerOptions>
    {
        private readonly ConsoleLoggerOptions option = new ConsoleLoggerOptions();

        public DummyConsoleLoggerOptionsMonitor(LogLevel level)
        {
            option.LogToStandardErrorThreshold = level;
        }

        public ConsoleLoggerOptions Get(string name)
        {
            return this.option;
        }

        public IDisposable OnChange(Action<ConsoleLoggerOptions, string> listener)
        {
            return new DummyDisposable();
        }

        public ConsoleLoggerOptions CurrentValue => this.option;

        private sealed class DummyDisposable : IDisposable
        {
            public void Dispose()
            {
            }
        }
    }

You can then use your ILoggerFactory like:

factory.AddProvider(
    new ConsoleLoggerProvider(
        new DummyConsoleLoggerOptionsMonitor(LogLevel.Debug)));