DotNetCore App log4net not logging when started via systemd

Question

I've programmed a C# app on Windows and have now deployed it on Linux. When I start the app via terminal as a normal (no sudo) user, the log4net works correctly. But when I set the app to run as a systemd, the app is working but the logging function is not.

Here my log4net.config:

<log4net>
  <root>
    <level value="INFO" />
  </root>
  <!-- myApp -->
  <logger name="myApp">
    <level value="DEBUG" />
    <appender-ref ref="app" />
  </logger>
  <appender name="app" type="log4net.Appender.RollingFileAppender">
    <file value="/var/client_name/log/myApp_v001/app.log" />
    <appendToFile value="true" />
    <rollingStyle value="Size" />
    <maxSizeRollBackups value="5" />
    <maximumFileSize value="10MB" />
    <staticLogFileName value="true" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%date [%thread] %level - %message%newline" />
    </layout>
  </appender>
  <!-- ExternalLibrary -->
  <logger name="ExternalLibrary">
    <level value="WARN" />
    <appender-ref ref="extLib" />
  </logger>
  <appender name="extLib" type="log4net.Appender.RollingFileAppender">
    <file value="/var/client_name/log/myApp_v001/extLib.log" />
    <appendToFile value="true" />
    <rollingStyle value="Size" />
    <maxSizeRollBackups value="5" />
    <maximumFileSize value="10MB" />
    <staticLogFileName value="true" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%date [%thread] %level %logger - %message%newline" />
    </layout>
  </appender>
</log4net>

On my C# app I'm setting the XmlConfigurator:

XmlConfigurator.Configure(logRepository, new FileInfo("log4net.config"));

On windows, while debugging the log4net saves the log files under c:/var/client_name/log/myApp_v001/*

Then I published the app for Linux and deployed it. On the Linux machine I've created a myApp.service file under /etc/systemd/system with following content:

[Unit]
Description=myApp Service
After=network.target remote-fs.target

[Service]
Type=simple
ExecStart=/opt/dotnet/dotnet /opt/client_name/myApp_v001/myApp.dll
ExecStartPre=/bin/sleep 10
Restart=always
User=normaluser
Group=normaluser

[Install]
WantedBy=multi-user.target

Then restarted systemctl and started the service manually:

sudo systemctl start myApp.service

The app runs and is working, but the log files are not being created.

Then I stopped the service

sudo systemctl stop myApp.service

And started the app without systemd:

cd /opt/client_name/myApp_v001/
dotnet myApp.dll

The app runs and the log files are being created accordingly.

The rights of the folder containing the logs are set to

drwxrw-rw- 2 normaluser normaluser

How can I make the logger to work also when being started by a systemd?

Used hardware/software:

Linux = Raspbian GNU/Linux 9 (stretch)

.Net-Core = Microsoft.NETCore.App 3.1.9

Answer 1

I got log4net to work with dotnet core systemd services by making the Log path relative.

I also believe that you may want to specify a WorkingDirectory in your Unit File. That way if you configure Log4Net's file appender to log to Logs/Service.log.txt, then you should see a Logs folder created in the $WorkingDirectory.

The other option is to use the built in journalctl to view logs.