ConfigureNLogFromCode.cs

using NLog;
using NLog.Config;
using NLog.Targets;
using System.IO;

namespace ProductName
{
	class Program
	{
		static void Main(string[] args)
		{
			ConfigureLogging(Path.GetFullPath("."), "ProductName");
		}

		private static void ConfigureLogging(string folder, string productName)
		{
			var config = new LoggingConfiguration();
			ConfigureConsoleLogging(config);
			ConfigureFileLogging(config, folder, productName);
			LogManager.Configuration = config;
		}

		private static void ConfigureFileLogging(
			LoggingConfiguration config, string folder, string productName)
		{
			Directory.CreateDirectory(folder);

			var target = new FileTarget()
			{
				Name = "file",
				Layout = "${date:format=yyyyMMdd.HHmmss} ${threadid}> [${level}] (${logger}) ${message}",
				ArchiveEvery = FileArchivePeriod.Day,
				MaxArchiveFiles = 7,
				FileName = Path.Combine(folder, productName + ".log"),
				ArchiveFileName = Path.Combine(folder, productName + ".bak"),
			};
			config.AddTarget("file", target);
			config.LoggingRules.Add(new LoggingRule("*", LogLevel.Debug, target));
		}

		private static void ConfigureConsoleLogging(LoggingConfiguration config)
		{
			var console = new ColoredConsoleTarget
			{
				Name = "console",
				Layout = "${message}",
				UseDefaultRowHighlightingRules = true,
				ErrorStream = false,
			};

			Action<LogLevel, ConsoleOutputColor> configure = (level, color) =>
			{
				console.RowHighlightingRules.Add(
					new ConsoleRowHighlightingRule(
						$"level == LogLevel.{level}",
						color,
						ConsoleOutputColor.NoChange));
			};

			configure(LogLevel.Trace, ConsoleOutputColor.DarkGray);
			configure(LogLevel.Debug, ConsoleOutputColor.Gray);
			configure(LogLevel.Info, ConsoleOutputColor.Cyan);
			configure(LogLevel.Warn, ConsoleOutputColor.Yellow);
			configure(LogLevel.Error, ConsoleOutputColor.Red);
			configure(LogLevel.Fatal, ConsoleOutputColor.Magenta);

			config.AddTarget("console", console);

			config.LoggingRules.Add(new LoggingRule("*", LogLevel.Debug, console));
		}
	}
}