Flawless Logger

FlawlessLogger.cs

using System;
using System.Collections.Concurrent;
using System.Diagnostics;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

namespace Blablabla
{
    public static class Logger
    {
        // Enable to turn on the logger in %temp% folder
        private const bool LogEnabled = true;

        // Enable to turn on the log cleanup (delete the old log files) when the relevant applications initialize the logger
        private const bool LogCleanup = true;

        public static void Log(string messageTemplate, params object[] parameters)
            => Log(string.Format(messageTemplate, parameters));

        public static void Log(string message)
        {
            if (LogEnabled)
            {
                Writer.Append($"{DateTime.Now.ToLongTimeString()} - #{Thread.CurrentThread.ManagedThreadId} - {message}");
            }
        }

        public static void Stop()
        {
            Writer.Cancel();
            MultiThreadFileWriter.Instance = null;
        }

        private static MultiThreadFileWriter Writer
        {
            get => MultiThreadFileWriter.Instance;
        }

        private class MultiThreadFileWriter
        {
            private const string Prefix = "test";
            private const int DelayInMs = 500;
            private readonly ConcurrentQueue<string> textToWrite = new();
            private readonly CancellationTokenSource cancellationSource = new();
 
            private MultiThreadFileWriter()
            {
                Task.Factory.StartNew(WriteToFile, TaskCreationOptions.LongRunning);
            }

            private static MultiThreadFileWriter writer;
            internal static MultiThreadFileWriter Instance
            {
                get => writer ??= new MultiThreadFileWriter();
                set => writer = value;
            }

            internal void Append(string line) 
                => textToWrite.Enqueue(line);

            private async Task WriteToFile()
            {
                // Initialization
                var path = Path.Combine(Path.GetTempPath(), $"{Prefix}-{Process.GetCurrentProcess().ProcessName}.log");

                // Clean up old log file
                if (LogCleanup && File.Exists(path))
                {
                    File.Delete(path);
                }

                while (true)
                {
                    if (cancellationSource.Token.IsCancellationRequested)
                    {
                        return;
                    }

                    using var w = File.AppendText(path);
                    while (textToWrite.TryDequeue(out string textLine))
                    {
                        await w.WriteLineAsync(textLine);
                    }
                    await w.FlushAsync();

                    // Avoid eating up the CPU by waiting for next iteration
                    await Task.Delay(DelayInMs, cancellationSource.Token);
                }
            }

            internal void Cancel()
            {
                cancellationSource.CancelAfter(DelayInMs+1);
            }
        }
    }
}