How do I use a GlobalContext property in a log4net appender name?

Question

I'm trying to customise a log4net file path to use a property I have set in the log4net.GlobalContext.Properties dictionary.

log4net.GlobalContext.Properties["LogPathModifier"] = "SomeValue";

I can see that this value is set correctly when debugging through it. and then in my configuration

<file type="log4net.Util.PatternString" 
      value="Logs\%appdomain_%property{LogPathModifier}.log" />

However, the output of this gives me "_(null).log" at the end of the path. What gives?

score 58 · Accepted Answer · answered Feb 21 '09 at 04:12

I ran into the same behavior and solved it by setting the global variable before calling the XmlConfigurator... Here is what I am successfully using:

log4net.config details:

<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender,log4net">
  <File type="log4net.Util.PatternString" value="App_Data/%property{LogName}" />
  ...
</appender>

Global.asax details:

private static readonly log4net.ILog log = log4net.LogManager.GetLogger("Global.asax");
void Application_Start(object sender, EventArgs e) 
{
    // Set logfile name and application name variables
    log4net.GlobalContext.Properties["LogName"] = GetType().Assembly.GetName().Name + ".log";
    log4net.GlobalContext.Properties["ApplicationName"] = GetType().Assembly.GetName().Name;

    // Load log4net configuration
    System.IO.FileInfo logfile = new System.IO.FileInfo(Server.MapPath("log4net.config"));
    log4net.Config.XmlConfigurator.ConfigureAndWatch(logfile);

    // Record application startup
    log.Debug("Application startup");
}

Hope this helps...

I was having exactly same problem, in my case i was trying to log into same file from 2 different processes. It was getting in 2 separate files, but setting the global variable before calling the XmlConfigurator in second app solved the problem. Thank you very much. +1 — Tara Singh, Sep 30 '11 at 19:19
i used `System.Reflection.Assembly.GetExecutingAssembly().GetName().Name` for the application name — Valamas, Jan 13 '14 at 01:54
@Dscoduc Which class contains Server.MapPath could you please share the details — Venkat, Aug 14 '17 at 05:23

score 16 · Answer 2 · edited Oct 07 '14 at 23:27

16

Add type=log4net.Util.PatternString into File element

edited Oct 07 '14 at 23:27

Noctis

11,507
3
43
82

answered Jun 01 '09 at 20:35

score 4 · Answer 3 · edited Oct 07 '14 at 23:28

The problem( I think) is that you GET(GetLogger) the logger before you set the name and load the config...

Try to do declare the logger like: private static log4net.ILog _pLog and then in the Application_Start do:

void Application_Start(object sender, EventArgs e) 
{
    // Set logfile name and application name variables
    log4net.GlobalContext.Properties["LogName"] = GetType().Assembly.GetName().Name + ".log";
    log4net.GlobalContext.Properties["ApplicationName"] = GetType().Assembly.GetName().Name;

    // Load log4net configuration
    System.IO.FileInfo logfile = new System.IO.FileInfo(Server.MapPath("log4net.config"));
    log4net.Config.XmlConfigurator.ConfigureAndWatch(logfile);

    //Get the loger
    _pLog = log4net.LogManager.GetLogger("Global.asax");

    // Record application startup
    pLog .Debug("Application startup");
}

So the sequence is:

// Set logfile name and application name variables
// Load log4net configuration
// get the logger
// Record application startup

score 1 · Answer 4 · answered Feb 18 '09 at 17:54

1

Has the logger been initialized through the global or main method in the application? It could be that the GlobalContext has not been initialize yet.

answered Feb 18 '09 at 17:54

Dillie-O

29,277
14
101
140

I have called LogManager.GetLogger() before setting the property. Also, logging is working correctly, its just that the file name is not picking up the custom value. – Long Pham Feb 19 '09 at 09:33

How do I use a GlobalContext property in a log4net appender name?

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