log4net doesn't create log file when deployed

问题:

Good morning everybody,

I have a log4net issue that didn't exist when I was developing on my local machine, but once I deployed the application to a server, log4net stopped working.

This is the server configuration : -Windows XP SP3 -IIS 7 -framework .Net v4

This is the log4net configuration in the web.config of the website:

<configuration>
      <log4net>
        <root>
          <level value="DEBUG" />
          <appender-ref ref="LogFileAppender" />
        </root>
        <appender name="LogFileAppender" type="log4net.Appender.RollingFileAppender">
          <param name="File" value="log.txt" />
          <param name="AppendToFile" value="true" />
          <rollingStyle value="Size" />
          <maxSizeRollBackups value="10" />
          <maximumFileSize value="30MB" />
          <staticLogFileName value="false" />
          <layout type="log4net.Layout.PatternLayout">
            <param name="ConversionPattern" value="%-5p%d{yyyy-MM-dd hh:mm:ss} – %m%n" />
          </layout>
        </appender>
      </log4net>
    </configuration>

I also have a class library and this is its App.config file:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,Log4net"/>
  </configSections>
  <log4net>
    <root>
      <level value="DEBUG" />
      <appender-ref ref="LogFileAppender" />
    </root>
    <appender name="LogFileAppender" type="log4net.Appender.RollingFileAppender" >
      <param name="File" value="log.txt" />
      <param name="AppendToFile" value="true" />
      <rollingStyle value="Size" />
      <maxSizeRollBackups value="10" />
      <maximumFileSize value="30MB" />
      <staticLogFileName value="true" />
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="%-5p%d{yyyy-MM-dd hh:mm:ss} – %m%n" />
      </layout>
    </appender>
  </log4net>
</configuration>

This is how I call the log function on every class:

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

...and this is how i call it :

log.Error("\n\t=>" + ex.GetBaseException().Message + "\n\r" + " @ " + Environment.StackTrace);

回答1:

It could be that you do not have permissions to write to the file 'log.txt'.

I don't know what the current directory would be but it's unlikely to be somewhere IIS can write to.

You need to create a folder somewhere and grant access for IIS to write to it, I understand you need to grant access to the IIS_IUSRS group and then specify the absolute path to that file. e.g.

<param name="File" value="D:\Logs\log.txt" />

..using the path to your preferred location.

回答2:

When it comes to writing log files I tend not to try and write my log files anywhere in the program files directory or anything in any virtual directory just because of the previous battles I've had with security issues. Currently I'm using something like the following for all my log4net log files:

<file type="log4net.Util.PatternString" value="${ALLUSERSPROFILE}/<Product Name>/Logs/<Program Name>/<Program Name>.log" />

${ALLUSERSPROFILE} is the key above. This directory typically doesn't have the security restrictions as virtual directory and the program files directory. I've found that I haven't had any trouble since I've been using this path.

This envrionment variable takes you to the ProgramData directory in Windows Vista, 7, 8, Server 2008 etc. I think XP takes you to a different place but still a directory with relaxed permissions.

On a side note your log statement above:

log.Error("\n\t=>" + ex.GetBaseException().Message + "\n\r" + " @ " + Environment.StackTrace);

Can be shortened to: log.Error(ex); Unless the formatting is a must. But if you write it like that and deploy your binaries with the pdbs the exceptions you log will contain the full stack trace and the line number the error occurred on.

Edit:

Log files will also fail to create if you have invalid log4net configuration. If you are sure that you have write access to the folder specified in your log4net configuration I would suggest enabling log4net debugging by first setting debug="true" in your log4net config section:

<log4net debug="true">
    ...
</log4net>

Setting the above debug flag will tell log4net to output all it's logging via windows trace listeners. To capture this trace listener output you will have to add a section like the following to your app.config:

<system.diagnostics>
  <trace autoflush="true">
    <listeners>
      <add 
        name="textWriterTraceListener" 
        type="System.Diagnostics.TextWriterTraceListener" 
        initializeData="C:\tmp\log4net.txt" />
    </listeners>
  </trace>
</system.diagnostics>

Make sure the path specified in the above trace listener config in app.config exists and that you have write access to the folder!

回答3:

I had the same problem myself and it turned out that I had forgot to set the "Build Action" for the configuration file. Therefore the log4net.config file was not deployed, and this is of course needed to make the application write the log file.

回答4:

The log folder directory should be given the permission under which IIS is running. e.g. if IIS is run as network service then add Network service account the directory and give full permission to it.

回答5:

Check with reference to following configuration in web.config. If everything good , check the write permission of inetpub sub-folder using the application pool owner. If not grant full permission.

Hope it will resolve your issue

<configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,     log4net" />
  </configSections>

  <log4net debug="true">
    <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
      <file value="logs\log.txt" />
      <appendToFile value="true" />
      <rollingStyle value="Size" />
      <maxSizeRollBackups value="10" />
      <maximumFileSize value="10MB" />
      <staticLogFileName value="true" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%-5p %d %5rms %-22.22c{1} %-18.18M - %m%n %newline--%newline" />
      </layout>
    </appender>
    <root>
      <level value="DEBUG" />
      <appender-ref ref="RollingLogFileAppender" />
    </root>
  </log4net>