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Question

I am following this tutorial: https://andrewlock.net/using-dependency-injection-in-a-net-core-console-application/

and accordingly installed the packages but log is not getting printed anywhere.

This is my code:

  var serviceProvider = new ServiceCollection()
            .AddLogging()
            .AddTransient<IFoo, Foo>(s =>
            {
                return new Foo()})
            .BuildServiceProvider();

            //configure console logging
            serviceProvider
                .GetService<ILoggerFactory>()
                .AddConsole(LogLevel.Debug);

 var logger = serviceProvider.GetService<ILoggerFactory>().CreateLogger<Program>();

            logger.LogError("Starting application");

Answer 1

Turns out the console logging provider doesn't immediately flush the messages to the console like it did in the net-core-1.x versions. It appears to run on a different thread. See this web page for info: https://github.com/aspnet/Logging/issues/631

You can add at the end of the Main function.

serviceProvider.Dispose();

or you can add .AddDebug()

            serviceProvider
            .GetService<ILoggerFactory>()
            .AddConsole(LogLevel.Debug)
            .AddDebug();

Answer 2

Creating a new ServiceProvider and HostBuilder may not be worth it if we just want a Logging in Console Application because it's a bit of extra caution to clean it up or dispose of. Rather, I would suggest just have Logging Factory to use logger and that will solve the logging if that is only what we want.

public static class ApplicationLogging
{
    public static ILoggerFactory LogFactory { get; } = LoggerFactory.Create(builder =>
        builder.ClearProviders(); 
        // Clear Microsoft's default providers (like eventlogs and others)
        builder.AddSimpleConsole(options =>
        {
            options.IncludeScopes = true;
            options.SingleLine = true;
            options.TimestampFormat = "hh:mm:ss ";
        });
        builder.AddApplicationInsights("instrument-key");
    });
    public static ILogger<T> CreateLogger<T>() => LogFactory.CreateLogger<T>();
}

static void Main(string[] args)
{
    var logger = ApplicationLogging.CreateLogger<Program>();
    logger.LogInformation("Let's do some work");
    logger.LogWarning("I am going Crazy now!!!");
    logger.LogInformation("Seems like we are finished our work!");
    Console.ReadLine();
}

Answer 3

I landed on this thread trying to troubleshoot why console logging didn't work and this answer documents what I found. Packages used: Microsoft.Extensions.Logging Microsoft.Extensions.Logging.Console Microsoft.Extensions.Logging.Debug

Application: .NET Core 2.2 Console (Microsoft.NET.Sdk, netcoreapp2.2) Using Microsoft.Extensions.Hosting.IHost, this is how I added console logging:

var hostBuilder = new HostBuilder()
                // Other Configuration omitted for brevity
                .ConfigureLogging((hostBuilderContext, loggingBuilder) =>
                {
                    loggingBuilder.AddConfiguration(hostBuilderContext.Configuration.GetSection("Logging"));
                    loggingBuilder.AddConsole(options =>
                    {
                        options.IncludeScopes = true;
                    });
                    loggingBuilder.AddDebug();
                });
// Start the application
await hostBuilder.RunConsoleAsync();

Interestingly, if I remove the options parameter in the call to AddConsole, I do not see any logging. I believe this is so because I use an ILogger in my code that emits log statements:

public class ClassThatLogs
{
    private readonly ILogger<ClassThatLogs> _logger;

    public ClassThatLogs(ILogger<ClassThatLogs> logger)
    {
        _logger = logger;
    }

    public void DoWork()
    {
        _logger.LogInformation("Working");
    }
}

Answer 4

If I publish the console app as:

single file _log.LogDebug provide no output

when I publish it as not a single file (so I only uncheck the single file option) _log.LogDebug provides outputs on the console all my debugging statements. No other changes than unchecking single file.

So by only unticking "produce single file" my _logging.LogDebug starts to write stuff to the console.

Seems to be this: https://github.com/serilog/serilog-settings-configuration/issues/244