Write log file to AppData with log4net Asp.net Core 2.2 not working

Question

I'm trying to write log file to AppData location, but it doesn't work. I've tried with env%{AppData}, env%{APPDATA}, %APPDATA%, ${AppData}, ${APPDATA} but no one works. If I use C:\Temp it does work though.

I use Asp.Net Core 2.2. and log4net 2.08.

Any suggestions?

<?xml version="1.0" encoding="utf-8" ?>
<log4net>
  <root>
    <level value="ALL" />
    <appender-ref ref="console" />
    <appender-ref ref="file" />
  </root>
  <appender name="console" type="log4net.Appender.ConsoleAppender">
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%-5level %date{dd-mm-yyyy HH:mm:ss} %logger [%thread] - %message %exception%newline" />
    </layout>
  </appender>
  <appender name="file" type="log4net.Appender.RollingFileAppender">
    <file value="${AppData}\MyApp\MyLogFile.log" />
    <appendToFile value="true" />
    <rollingStyle value="Size" />
    <maxSizeRollBackups value="5" />
    <maximumFileSize value="10MB" />
    <staticLogFileName value="true" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%-5level %date{dd-mm-yyyy HH:mm:ss} %logger [%thread] - %message %exception%newline" />
    </layout>
  </appender>
</log4net>

You may find useful this one : https://stackoverflow.com/questions/2815940/where-will-log4net-create-this-log-file — Grigoris Loukidis, May 27 '19 at 12:04
I've also found this: https://stackoverflow.com/a/55539847/568680, it uses ` — eyal, May 27 '19 at 12:15
Thanks @Grigoris Loukidis and @eyal! I created a new post with my answer. — Joel Wiklund, May 27 '19 at 16:27

Joel Wiklund · Accepted Answer · 2022-11-19T15:37:26.397

For anyone with the same problems I had:

Nuget (Install):

log4net
Microsoft.Extensions.Options.ConfigurationExtensions
Microsoft.Extensions.Logging.Console
Microsoft.Extensions.Logging.Debug
Microsoft.Extensions.Logging.Log4Net.AspNetCore

AssemblyInfo.cs:

[assembly: log4net.Config.XmlConfigurator(ConfigFile = "log4net.config", Watch = true)]

appsettings.json:

"Log4NetConfigFile": {
    "Name": "log4net.config"
  },

Program.cs

using Microsoft.Extensions.Logging; //Had to write manually

public static void Main(string[] args)
{
    var logRepo = LogManager.GetRepository(Assembly.GetEntryAssembly());
    log4net.GlobalContext.Properties["LogPath"] = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "MyApp");
    log4net.Config.XmlConfigurator.Configure(logRepo, new FileInfo("log4net.config"));
    
    CreateWebHostBuilder(args).Build().Run();
}

public static IWebHostBuilder CreateWebHostBuilder(string[] args) => WebHost.CreateDefaultBuilder(args)
    .ConfigureLogging((webHostBuilderContext, loggingBuilder) =>
    {
        loggingBuilder.AddLog4Net();
    })
    .UseStartup<Startup>();
}

Set log4net.config to Copy to Output directory: Copy Always

log4net.config:

<?xml version="1.0" encoding="utf-8" ?>
<log4net>
  <root>
    <level value="ALL" />
    <appender-ref ref="console" />
    <appender-ref ref="file" />
  </root>
  <appender name="console" type="log4net.Appender.ConsoleAppender">
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%-5level %date{dd-mm-yyyy HH:mm:ss} %logger [%thread] - %message %exception%newline" />
    </layout>
  </appender>
  <appender name="file" type="log4net.Appender.RollingFileAppender">
    <file type="log4net.Util.PatternString" value="%property{LogPath}\MyLogFile.log" />
    <appendToFile value="true" />
    <rollingStyle value="Size" />
    <maxSizeRollBackups value="5" />
    <maximumFileSize value="10MB" />
    <staticLogFileName value="true" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%-5level %date{dd-mm-yyyy HH:mm:ss} %logger [%thread] - %message %exception%newline" />
    </layout>
  </appender>
</log4net>

HomeController.cs

private static readonly log4net.ILog log = log4net.LogManager.GetLogger(typeof(HomeController));

public HomeController()
{
    log.Info("Starting GenerateDebugLog method...");
}

This was a key piece for me: `using Microsoft.Extensions.Logging; //Had to write manually` — jglouie, Nov 21 '21 at 20:50

Write log file to AppData with log4net Asp.net Core 2.2 not working

1 Answers1