how to use serilog logger in asp.net core

Serilog is a popular logging framework for .NET applications. Here are the steps to declare Serilog in Program.cs, use it in appsettings.json, inject it into a controller class, and create separate classes and interfaces for Serilog to customize its methods:

Declare Serilog in Program.cs: In the Main method of Program.cs, you can configure Serilog by calling the UseSerilog method on the IWebHostBuilder instance. Here's an example:

using Serilog;
using Serilog.Events;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;

public class Program
{
    public static void Main(string[] args)
    {
        Log.Logger = new LoggerConfiguration()
            .MinimumLevel.Debug()
            .WriteTo.Console()
            .WriteTo.File("log.txt", rollingInterval: RollingInterval.Day)
            .CreateLogger();

        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .UseSerilog()
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup();
            });
}

Use Serilog in appsettings.json: You can use Serilog in appsettings.json by adding a "Serilog" section and configuring it with the desired sink(s) and minimum log level. Here's an example:

{
  "Serilog": {
    "MinimumLevel": {
      "Default": "Debug",
      "Override": {
        "Microsoft": "Warning",
        "System": "Warning"
      }
    },
    "WriteTo": [
      {
        "Name": "Console"
      },
      {
        "Name": "File",
        "Args": {
          "path": "log.txt",
          "rollingInterval": "Day"
        }
      }
    ]
  }
}

Use Serilog dependency injection in a controller class: You can use Serilog in a controller class by adding a constructor parameter of type ILogger (where T is the name of your controller class). The ILogger instance will be automatically injected by the ASP.NET Core dependency injection system. Here's an example:

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

namespace MyWebApp.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger _logger;

        public HomeController(ILogger logger)
        {
            _logger = logger;
        }

        public IActionResult Index()
        {
            _logger.LogInformation("Index page visited.");
            return View();
        }
    }
}

Create a separate class and interface for Serilog to customize its methods: You can create a separate class and interface for Serilog to customize its methods by implementing the ILogger interface and passing it to the ILoggerFactory. Here's an example:

using Serilog;
using Microsoft.Extensions.Logging;
using System;

public interface IMyLogger
{
    void Log(LogLevel logLevel, string message);
}

public class MyLogger : IMyLogger
{
    private readonly ILogger _logger;

    public MyLogger()
    {
        _logger = new LoggerConfiguration()
            .WriteTo.Console()
            .CreateLogger();
    }

    public void Log(LogLevel logLevel, string message)
    {
        switch (logLevel)
        {
            case LogLevel.Trace:
                _logger.Verbose(message);
                break;
            case LogLevel.Debug:
                _logger.Debug(message);
                break;
            case LogLevel.Information:
                _logger.Information(message);
                break;
            case LogLevel.Warning:
                _logger.Warning(message);
                break;
            case LogLevel.Error:
                _logger.Error(message);
                break;
            case LogLevel.Critical:
                _logger.Fatal(message);
                break;
            case LogLevel.None:
                break;
            default:
                throw new ArgumentOutOfRangeException(nameof(logLevel), logLevel, null);
        }
    }
}

You can then register the MyLogger class and interface with the ASP.NET Core dependency injection system in the Startup.cs file like this:

public void ConfigureServices(IServiceCollection services)
{
    services.AddSingleton();
    services.AddControllers();
}

And then use the IMyLogger interface in a controller like this:

public class HomeController : Controller
{
    private readonly IMyLogger _logger;

    public HomeController(IMyLogger logger)
    {
        _logger = logger;
    }

    public IActionResult Index()
    {
        _logger.Log(LogLevel.Information, "Index page visited.");
        return View();
    }
}

Hello Meghana,

Please refer below links:

https://www.codeproject.com/Articles/5344667/Logging-with-Serilog-in-ASP-NET-Core-Web-API#:~:text=Create%20ASP.NET%20Core%20Web%20API%20Project&text=Choose%20.,AspNetCore%20.

https://codingsonata.com/logging-with-serilog-in-asp-net-core-web-api/

https://procodeguide.com/programming/aspnet-core-logging-with-serilog/

Thanks

Naimish Makwana

Hello Meghana,

You can refer this thread,

https://www.c-sharpcorner.com/article/serilog-in-asp-net-core-3-1/

https://blog.christian-schou.dk/use-serilog-with-asp-net-core-net6/