Write to a file from multiple threads asynchronously c#

Question

Here is my situation. I would like to make writing to the file system as efficient as possible in my application. The app is multi-threaded and each thread can possibly wr

Answer 1

Save to log with Queue and multiple threads (.Net Core 2.2 linux sample - tested)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;
// add
using System.Security.Cryptography.X509Certificates;
using System.Threading;
using System.Net;
using System.Net.Sockets;
using System.Net.Security;
using System.Security.Authentication;
using System.IO;
using System.Timers;

namespace LogToFile
{
    class Program
    {
        public static Logger logger = new Logger("debug.log");

        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");

            logger.add("[001][LOGGER STARTING]");

            Thread t0 = new Thread(() => DoWork("t0"));
            t0.Start();

            Thread t1 = new Thread(() => DoWork("t1"));
            t1.Start();

            Thread t2 = new Thread(() => DoWork("t2"));
            t2.Start();

            Thread ts = new Thread(() => SaveWork());
            ts.Start();
        }

        public static void DoWork(string nr){
            while(true){
                logger.add("Hello from worker .... number " + nr);
                Thread.Sleep(300);
            }
        }

        public static void SaveWork(){
            while(true){
                logger.saveNow();
                Thread.Sleep(50);
            }
        }
    }

    class Logger
    {
        // Queue import: 
        // using System.Collections
        public Queue logs = new Queue();
        public string path = "debug.log";

        public Logger(string path){
            this.path = path;
        }

        public void add(string t){
            this.logs.Enqueue("[" + currTime() +"] " + t);
        }

        public void saveNow(){
            if(this.logs.Count > 0){
                // Get from queue
                string err = (string) this.logs.Dequeue();
                // Save to logs
                saveToFile(err, this.path);
            }
        }

        public bool saveToFile(string text, string path)
        {
            try{
                // string docPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
                // text = text + Environment.NewLine;
                using (StreamWriter sw = File.AppendText(path))
                {
                    sw.WriteLine(text);
                    sw.Close();
                }
            }catch(Exception e){
                // return to queue
                this.logs.Enqueue(text + "[SAVE_ERR]");
                return false;
            }
            return true;
        }

        public String currTime(){
            DateTime d = DateTime.UtcNow.ToLocalTime();
            return d.ToString("yyyy-MM-dd hh:mm:ss");
        }
    }
}

Compile (Save to: LogToFile/Program.cs):

dotnet new console -o LogToFile
cd LogToFile
dotnet build
dotnet run

Stop app CTRL+C and see log file

cat debug.log