Extensions: Bug: LogDebug and LogTrace don't produce any output on the console window

[pstricks-fans]

I am learning how to use the built-in .net core logging from Microsoft.Extensions.*. I found a strange output as follows. LogTrace and LogDebug don't produce any output on the output window. What causes this issue?

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System;

class Foo
{
    static void Main(string[] args)
    {
        Console.WriteLine("Begin...");
        IServiceCollection sc = new ServiceCollection()
            .AddLogging();

        IServiceProvider isp = sc.BuildServiceProvider();

        using (ILoggerFactory ilf = isp.GetRequiredService<ILoggerFactory>())
        {
            ilf.AddConsole() ;

            ILogger logger = ilf.CreateLogger<Program>();
            logger.LogTrace("Trace...");
            logger.LogDebug("Debug...");
            logger.LogInformation("Information...");
            logger.LogWarning("Warning...");
            logger.LogError("Error...");
            logger.LogCritical("Critical...");
        }
        Console.WriteLine("End...");
    }
}

[gfoidl]

Is Log filtering enabled?

It's not a bug, it's not read docs :wink:

[brandondahler]

For your particular case, here's the subsection that is applicable:

If you don't explicitly set the minimum level, the default value is Information, which means that Trace and Debug logs are ignored.

https://docs.microsoft.com/en-us/aspnet/core/fundamentals/logging/?view=aspnetcore-2.2#default-minimum-level

---

To configure it to show trace and debug, assuming you're using v2.1.1 (since ILoggerFactory.AddConsole() was deprecated in v2.2), you'd have to add both of the calls that have LogLevel.Trace specified:
``` C#
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Begin...");
IServiceCollection sc = new ServiceCollection()
.AddLogging(l => l.SetMinimumLevel(LogLevel.Trace)); // <==

        IServiceProvider isp = sc.BuildServiceProvider();

        using (ILoggerFactory ilf = isp.GetRequiredService<ILoggerFactory>())
        {
            ilf.AddConsole(LogLevel.Trace);  // <==

            ILogger logger = ilf.CreateLogger<Program>();
            logger.LogTrace("Trace...\r\n");
            logger.LogDebug("Debug...\r\n");
            logger.LogInformation("Information...\r\n");
            logger.LogWarning("Warning...\r\n");
            logger.LogError("Error...\r\n");
            logger.LogCritical("Critical...\r\n");
        }
        Console.WriteLine("End...");
    }
}

In 3.0, you'd have this code instead:
``` C#
   class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Begin...");
            IServiceCollection sc = new ServiceCollection()
                .AddLogging(l => l
                    .AddConsole()
                    .SetMinimumLevel(LogLevel.Trace));

            IServiceProvider isp = sc.BuildServiceProvider();

            // No need to get a ILoggerFactory
            ILogger logger = isp.GetRequiredService<ILogger<Program>>();

            logger.LogTrace("Trace...");
            logger.LogDebug("Debug...");
            logger.LogInformation("Information...");
            logger.LogWarning("Warning...");
            logger.LogError("Error...");
            logger.LogCritical("Critical...");

            // Console logger is now queued on a background thread
            Thread.Sleep(1000);

            Console.WriteLine("End...");
        }
    }

[pstricks-fans]

@brandondahler Thank you very much for your detailed answer. This kind of response is extremely understandable and useful.