log4net logger not writing my logs to file, but ASP.NET log messages are written - asp.net-core

Question

I have an ASP.NET Core 3.1 Razor pages web site, and am trying to add log4net to it, but can't get logging to work properly. I have referenced the Microsoft.Extensions.Logging.Log4Net.AspNetCore Nuget package and associated dependencies.
I added a log4net.config file...
<?xml version="1.0" encoding="utf-8"?>
<log4net>
<appender name="RollingFileAppender"
type="log4net.Appender.RollingFileAppender">
<param name="File"
value="MyWebSite.log" />
<appendToFile value="true" />
<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="2" />
<maximumFileSize value="5MB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-7level %logger - %message%newline%exception" />
</layout>
</appender>
<appender name="Console" type="log4net.Appender.ConsoleAppender">
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date %5level %logger.%method [%line] - MESSAGE: %message%newline %exception" />
</layout>
</appender>
<root>
<level value="DEBUG" />
<appender-ref ref="RollingFileAppender" />
</root>
</log4net>
I changed Program.cs to look like this...
public class Program {
public static void Main(string[] args) =>
CreateHostBuilder(args).Build().Run();
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureWebHostDefaults(webBuilder => {
webBuilder.UseStartup<Startup>();
}).ConfigureLogging(builder => {
builder.SetMinimumLevel(LogLevel.Trace);
builder.AddLog4Net("log4net.config");
});
}
I tried using this on the site home page, as follows...
public class IndexModel : PageModel {
private readonly ILogger<IndexModel> _logger;
public IndexModel(ILogger<IndexModel> logger) {
_logger = logger;
}
public void OnGet() {
_logger.LogDebug("Home page loading");
}
}
However, the log file did not contain the message I added.
I can see that logging is working to a degree, as the log file was created, and the first three lines were...
2020-10-18 16:27:59,052 INFO Microsoft.Hosting.Lifetime.? [?] - MESSAGE: Application started. Press Ctrl+C to shut down.
2020-10-18 16:27:59,065 INFO Microsoft.Hosting.Lifetime.? [?] - MESSAGE: Hosting environment: Development
2020-10-18 16:27:59,066 INFO Microsoft.Hosting.Lifetime.? [?] - MESSAGE: Content root path:
...but then I don't get anything else.
To check it was all being set up correctly, I added the following lines inside the Onget() method...
ILoggerRepository repository = log4net.LogManager.GetAllRepositories().FirstOrDefault();
RollingFileAppender appender = repository.GetAppenders().OfType<RollingFileAppender>().FirstOrDefault();
string logFile = appender.File;
At run time, the logFile variable is correctly set to the path to the expected log file, so it looks like it has initialised fine.
I tried going the old-fashioned root and newing up an instance of the logger as follows...
log4NetLogger = LogManager.GetLogger(typeof(IndexModel));
...and this worked fine.
So, I can log, but only by creating the logger manually, not by injection.
Anyone any idea what I'm doing wrong here? Thanks
Update Having just found out how to debug log4net, I added the following line in the ConfigureServices method in Startupcs...
log4net.Util.LogLog.InternalDebugging = true;
This resulted in the following being sent to the output panel...
log4net: log4net assembly [log4net, Version=2.0.8.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a]. (.NET Framework [.NET Core 3.1.4] on Microsoft Windows 10.0.18363)
log4net: defaultRepositoryType [log4net.Repository.Hierarchy.Hierarchy]
log4net: Creating repository for assembly [Microsoft.Extensions.Logging.Log4Net.AspNetCore, Version=3.1.0.0, Culture=neutral, PublicKeyToken=5d1104efbd0e675d]
log4net: Assembly [Microsoft.Extensions.Logging.Log4Net.AspNetCore, Version=3.1.0.0, Culture=neutral, PublicKeyToken=5d1104efbd0e675d] Loaded From [Not supported on .NET Core]
log4net: Assembly [Microsoft.Extensions.Logging.Log4Net.AspNetCore, Version=3.1.0.0, Culture=neutral, PublicKeyToken=5d1104efbd0e675d] does not have a RepositoryAttribute specified.
log4net: Assembly [Microsoft.Extensions.Logging.Log4Net.AspNetCore, Version=3.1.0.0, Culture=neutral, PublicKeyToken=5d1104efbd0e675d] using repository [log4net-default-repository] and repository type [log4net.Repository.Hierarchy.Hierarchy]
log4net: Creating repository [log4net-default-repository] using type [log4net.Repository.Hierarchy.Hierarchy]
log4net: configuring repository [log4net-default-repository] using XML element
log4net: Configuring Repository [log4net-default-repository]
log4net: Configuration update mode [Merge].
log4net: Logger [root] Level string is [DEBUG].
log4net: Logger [root] level set to [name="DEBUG",value=30000].
log4net: Loading Appender [RollingFileAppender] type: [log4net.Appender.RollingFileAppender]
log4net: Setting Property [File] to String value [MyWebSite.log]
log4net: Setting Property [AppendToFile] to Boolean value [True]
log4net: Setting Property [LockingModel] to object [log4net.Appender.FileAppender+MinimalLock]
log4net: Setting Property [RollingStyle] to RollingMode value [Size]
log4net: Setting Property [MaxSizeRollBackups] to Int32 value [2]
log4net: Setting Property [MaximumFileSize] to String value [5MB]
log4net: Setting Property [StaticLogFileName] to Boolean value [True]
log4net: Converter [message] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [newline] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Setting Property [ConversionPattern] to String value [%date [%thread] %-7level %logger - %message%newline%exception]
log4net: Converter [date] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [literal] Option [ [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [thread] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [literal] Option [] ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [level] Option [] Format [min=7,max=2147483647,leftAlign=True]
log4net: Converter [literal] Option [ ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [logger] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [literal] Option [ - ] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [message] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [newline] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Converter [exception] Option [] Format [min=-1,max=2147483647,leftAlign=False]
log4net: Setting Property [Layout] to object [log4net.Layout.PatternLayout]
log4net: Searched for existing files in [PATHTOPROJECT]
log4net: curSizeRollBackups starts at [0]
log4net: Opening file for writing [PATHTOPROJECT\MyWebSite.log] append [True]
log4net: Created Appender [RollingFileAppender]
log4net: Adding appender named [RollingFileAppender] to logger [root].
log4net: Hierarchy Threshold []
Microsoft.Hosting.Lifetime: Information: Application started. Press Ctrl+C to shut down.
Microsoft.Hosting.Lifetime: Information: Hosting environment: Development
Microsoft.Hosting.Lifetime: Information: Content root path: PATHTOPROJECT
Not sure if this helps, as it doesn't seem to show any errors. The path is correct, and points to the log file that is written.

Answer 1

Have you changed the default logging level set in your appSettings.json to "Debug"? If it's set to "Information" then debug logging messages won't show.