Castle File Logger

A simple and lightweight log-to-file provider writing log entries by Microsoft.Extensions.Logging.ILogger to disk file for offline analysis.

• Adds the provider using an ILoggerFactory extension making integration and configuration quick and easy.
• Uses existing Microsoft.Extensions.Logging references minimizing dependencies and coding footprint.
• Available as a NuGet Package or C# Class Library for fast and easy integration.
• ASP.NET Core MVC Framework friendly.
• Design and implementation deeply influenced by Microsoft.Extensions.Logging.AzureAppServices.BatchingLogger

This repository is provided for those wishing to learn and expand their knowledge. There are several feature-rich loggers available providing these features and so much more. For those seeking more robust features and options, we recommend using Serilog and log4net.

Setup

Begin by installing the NuGet Package or add the C# Class Library to your project.

Add one line of code to your Program.cs file.

public static IWebHost BuildWebHost(string[] args) =>
	WebHost.CreateDefaultBuilder(args)
		.ConfigureLogging(logging => logging.AddFile())	// <-- add this line
		.UseStartup<Startup>()
		.Build();

Build and run. Log entries written to your existing ILogger will appear in your project folder as: ~/Logs/log-YYYYMMDD.txt.

Sample Projects

The sample projects demonstrate the use of logging and ILogger within your ASP.NET Core MVC Web Application projects. These projects indirectly demonstrate File Logging by helping investigators produce results quickly and easily using Core services provided by Microsoft.Extensions.Logging.ILogger.

SampleApp

The SampleApp ASP.NET Core Web Application Project demonstrates how simple use of the File Logger extension can be. After adding the library and the the above-mentioned one line of code to Program.cs, we add a few more lines to the HomeController to demonstrate output of basic log entries.

namespace SampleApp.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;

        public HomeController(ILogger<HomeController> logger)
        {
            _logger = logger;
        }
        public IActionResult Index()
        {
            _logger.LogInformation("Method: HomeController.Index() called.");
            return View();
        }
    }
}

Build and run. Review log entries written to ILogger in: ~/Logs/log-YYYYMMDD.txt.

SampleAppDI

The SampleAppDI ASP.NET Core Web Application Project demonstrates the use of Dependency Injection (DI) of the ILogger object into third-party classes not derived from Conroller. This is an advanced topic for those wishing to use the ILogger from Business Logic and Data Access layer classes.

Begin by modeling your class constructor with the desired class object, in this case ILogger:

namespace SampleAppDI
{
    /// <summary>
    /// A class representing Business Logic Layer (BLL) or Data Access Layer (DAL)
    /// methods, properties and functions.
    /// </summary>
    public class MyTestClass
    {
        private readonly ILogger<MyTestClass> _logger;

        public MyTestClass(ILogger<MyTestClass> logger)
        {
            _logger = logger;
            _logger.LogInformation("MyTestClass() instantiated.");
        }

        public string Foo()
        {
            _logger.LogInformation("Method: MyTestClass.Foo() called.");
            return "Hello, world.";
        }
    }
}

Next, instantiate your class using DI from the Controller-derived class:

namespace SampleAppDI.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;
        private readonly MyTestClass _test;

        public HomeController(ILogger<HomeController> logger, MyTestClass test)
        {
            _logger = logger;
            _test = test;
        }

        public IActionResult Index()
        {
            _logger.LogInformation("Method: HomeController.Index() called.");
            _logger.LogInformation(@"MyTestInstance.Foo() = {0}", _test.Foo());
            return View();
        }
    }
}

Finally, register the class to be instantiated using DI in the ConfigureServices() method of Startup.cs:

// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
    services.AddTransient<MyTestClass>();	// <-- add this line
    services.AddMvc();
}

Build and run. Review log entries written to ILogger in: ~/Logs/log-YYYYMMDD.txt.