LoggingConfigurator.cs

using System.Reflection;
using log4net;
using log4net.Appender;
using log4net.Core;
using log4net.Layout;
using log4net.Repository.Hierarchy;
using Microsoft.Extensions.Configuration;
// also need Microsoft.Extensions.Configuration.Binding for the Bind to work

namespace ControlCenter.Model
{
    // First cut at configuring log4net through code in dotnet core
    public class LoggingConfigurator
    {
        class Log4NetSettings
        {
            public string FileName { get; set; }
        }

        public static void ConfigureLogging(IConfiguration config)
        {
            var settings  = new Log4NetSettings();
            config.Bind("log4net", settings);

            var hierarchy = (Hierarchy)LogManager.GetRepository(Assembly.GetExecutingAssembly());
            hierarchy.Root.RemoveAllAppenders();
            PatternLayout fileLayout = new PatternLayout();
            fileLayout.ConversionPattern = "[%-5level] %date{yyyy-MM-dd HH:mm:ss}: %message%newline";
            fileLayout.ActivateOptions();

            PatternLayout consoleLayout = new PatternLayout();
            consoleLayout.ConversionPattern = "[%-5level] %date{yyyy-MM-dd HH:mm:ss}: %message%newline";
            consoleLayout.ActivateOptions();

            RollingFileAppender roller = new RollingFileAppender();
            roller.AppendToFile = true;
            roller.File = settings.FileName ?? "log.txt";
            roller.MaximumFileSize = "100MB";
            roller.MaxSizeRollBackups = 5;
            roller.RollingStyle = RollingFileAppender.RollingMode.Size;
            roller.CountDirection = -1;
            roller.LockingModel = new FileAppender.MinimalLock();
            roller.Layout = fileLayout;
            roller.ActivateOptions();
            hierarchy.Root.AddAppender(roller);

            ConsoleAppender console = new ConsoleAppender();
            console.Layout = consoleLayout;
            console.ActivateOptions();
            hierarchy.Root.AddAppender(console);

            hierarchy.Root.Level = Level.Info;

            var nhiblog = hierarchy.GetLogger("NHiberate");
            nhiblog.Repository.Threshold = Level.Warn;

            hierarchy.Configured = true;
        }

    }
}