Log4Net: set Max backup files on RollingFileAppender with rolling Date

Question

I have the following configuration, but I have not able to find any documentation on how to set a maximum backup files on date rolling style. I know that you can do this with size rolling style by using the maxSizeRollBackups.

<appender name="AppLogFileAppender" type="log4net.Appender.RollingFileAppender">
    <file value="mylog.log" />
    <appendToFile value="true" />
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
    <rollingStyle value="Date" />
    <datePattern value=".yyMMdd.'log'" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%d %-5p %c - %m%n"  />
    </layout>
</appender>

Answer 1

Not sure exactly what you need. Below is an extract from one of my lo4net.config files:

  <appender name="RollingFile" type="log4net.Appender.RollingFileAppender">
    <param name="File" value="App_Data\log"/>
    <param name="DatePattern" value=".yyyy-MM-dd-tt&quot;.log&quot;"/>
    <param name="AppendToFile" value="true"/>
    <param name="RollingStyle" value="Date"/>
    <param name="StaticLogFileName" value="false"/>
    <param name="maxSizeRollBackups" value="60" />
    <layout type="log4net.Layout.PatternLayout">
      <param name="ConversionPattern" value="%r %d [%t] %-5p %c - %m%n"/>
    </layout>
  </appender>

Answer 2

You can't.

from log4net SDK Reference
RollingFileAppender Class

**CAUTION**

A maximum number of backup files when rolling on date/time boundaries is not supported.

Answer 3

I spent some time looking into this a few months ago. v1.2.10 doesn't support deleting older log files based on rolling by date. It is on the task list for the next release. I took the source code and added the functionality myself, and posted it for others if they are interested. The issue and the patch can be found at https://issues.apache.org/jira/browse/LOG4NET-27 .

Answer 4

Even though its not supported, here is how I handled this situation:

This is my configuration:

    <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
        <file value="C:\logs\LoggingTest\logfile.txt" />
        <appendToFile value="true" />
        <rollingStyle value="Composite" />
        <datePattern value="yyyyMMdd" />
        <maxSizeRollBackups value="10" />
        <maximumFileSize value="1MB" />
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%date  - %message%newline" />
        </layout>
    </appender>

On application start up I do:

 XmlConfigurator.Configure();
 var date = DateTime.Now.AddDays(-10);
 var task = new LogFileCleanupTask();
 task.CleanUp(date);

---

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

using log4net;
using log4net.Appender;
using log4net.Config;

    public class LogFileCleanupTask
    {
        #region - Constructor -
        public LogFileCleanupTask()
        {
        }
        #endregion

        #region - Methods -
        /// <summary>
        /// Cleans up. Auto configures the cleanup based on the log4net configuration
        /// </summary>
        /// <param name="date">Anything prior will not be kept.</param>
        public void CleanUp(DateTime date)
        {
            string directory = string.Empty;
            string filePrefix = string.Empty;

            var repo = LogManager.GetAllRepositories().FirstOrDefault(); ;
            if (repo == null)
                throw new NotSupportedException("Log4Net has not been configured yet.");

            var app = repo.GetAppenders().Where(x => x.GetType() == typeof(RollingFileAppender)).FirstOrDefault();
            if (app != null)
            {
                var appender = app as RollingFileAppender;

                directory = Path.GetDirectoryName(appender.File);
                filePrefix = Path.GetFileName(appender.File);

                CleanUp(directory, filePrefix, date);
            }
        }

        /// <summary>
        /// Cleans up.
        /// </summary>
        /// <param name="logDirectory">The log directory.</param>
        /// <param name="logPrefix">The log prefix. Example: logfile dont include the file extension.</param>
        /// <param name="date">Anything prior will not be kept.</param>
        public void CleanUp(string logDirectory, string logPrefix, DateTime date)
        {
            if (string.IsNullOrEmpty(logDirectory))
                throw new ArgumentException("logDirectory is missing");

            if (string.IsNullOrEmpty(logDirectory))
                throw new ArgumentException("logPrefix is missing");

            var dirInfo = new DirectoryInfo(logDirectory);
            if (!dirInfo.Exists)
                return;

            var fileInfos = dirInfo.GetFiles("{0}*.*".Sub(logPrefix));
            if (fileInfos.Length == 0)
                return;

            foreach (var info in fileInfos)
            {
                if (string.Compare(info.Name, logPrefix, true) != 0)
                {
                    if (info.CreationTime < date)
                    {
                        info.Delete();
                    }
                }
            }

        }
        #endregion
    }

Answer 5

I like your answer but the only question I have is what is the Sub extension?

var fileInfos = dirInfo.GetFiles("{0}*.*".*Sub*(logPrefix));