How to use log4net in Asp.net core 2.0

I configure log4net in my asp.net core 2.0 application as mentioned in this article LINK

program.cs

public static void Main(string[] args)
{
    var logRepository = LogManager.GetRepository(Assembly.GetEntryAssembly());
    XmlConfigurator.Configure(logRepository, new FileInfo("log4net.config"));

    BuildWebHost(args).Run();
}

HomeController

public class HomeController : Controller
{
    private static readonly log4net.ILog log = log4net.LogManager.GetLogger(typeof(HomeController));

    public IActionResult Error()
    {
        log.Info("Hello logging world!");
        return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
    }
}

log4net.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <log4net>
    <root>
      <level value="ALL" />
      <appender-ref ref="RollingFile" />
    </root>
    <appender name="RollingFile" type="log4net.Appender.FileAppender">
      <file value="‪C:\Temp\app.log" /> 
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%-5p %d{hh:mm:ss} %message%newline" />
      </layout>
    </appender>
  </log4net>
</configuration>

Unlucky!, I didn't see any file generated in ‪C:\Temp\app.log directory. What would be the mistake? how to configure log4net for asp.net core 2.0?

Solution 1:

There is a third-party log4net adapter for the ASP.NET Core logging interface.

Only thing you need to do is pass the ILoggerFactory to your Startup class, then call

loggerFactory.AddLog4Net();

and have a config in place. So you don't have to write any boiler-plate code.

More info here

Solution 2:

I am successfully able to log a file using the following code

public static void Main(string[] args)
{
    XmlDocument log4netConfig = new XmlDocument();
    log4netConfig.Load(File.OpenRead("log4net.config"));
    var repo = log4net.LogManager.CreateRepository(Assembly.GetEntryAssembly(),
               typeof(log4net.Repository.Hierarchy.Hierarchy));
    log4net.Config.XmlConfigurator.Configure(repo, log4netConfig["log4net"]);

    BuildWebHost(args).Run();
}

log4net.config in website root

<?xml version="1.0" encoding="utf-8" ?>
<log4net>
  <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
    <file value="C:\Temp\" />
    <datePattern value="yyyy-MM-dd.'txt'"/>
    <staticLogFileName value="false"/>
    <appendToFile value="true"/>
    <rollingStyle value="Date"/>
    <maxSizeRollBackups value="100"/>
    <maximumFileSize value="15MB"/>
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%date [%thread] %-5level App  %newline %message %newline %newline"/>
    </layout>
  </appender>
    <root>
      <level value="ALL"/>
      <appender-ref ref="RollingLogFileAppender"/>
    </root>
</log4net>

Solution 3:

Still looking for a solution? I got mine from this link .

All I had to do was add this two lines of code at the top of "public static void Main" method in the "program class".

 var logRepo = LogManager.GetRepository(Assembly.GetEntryAssembly());
 XmlConfigurator.Configure(logRepo, new FileInfo("log4net.config"));

Yes, you have to add:

1. Microsoft.Extensions.Logging.Log4Net.AspNetCore using NuGet.
2. A text file with the name of log4net.config and change the property(Copy to Output Directory) of the file to "Copy if Newer" or "Copy always".

You can also configure your asp.net core application in such a way that everything that is logged in the output console will be logged in the appender of your choice. You can also download this example code from github and see how i configured it.