Log4Net, how to add a custom field to my logging

Question

I use the log4net.Appender.AdoNetAppender appender.
My log4net table are the following fields [Date],[Thread],[Level],[Logger],[Message],[Exception]

Answer 1

Here is a working version with some personalized preferences. I added a custom column for storing a generated exception code.

1) Add your custom column(exceptionCode here) to Log4net config:

<commandText value="INSERT INTO Log([Date],[Thread],[Level],[Logger],[Message],[Exception],[ExceptionCode]) 
VALUES (@log_date, @thread, @log_level, @logger, @message, @exception,@exceptionCode)" />

<parameter>
    <parameterName value="@exceptionCode" />
    <dbType value="String" />
    <size value="11" />
    <layout type="Common.Utils.LogHelper.Log4NetExtentedLoggingPatternLayout">
        <conversionPattern value="%exceptionCode{Code}" />
    </layout>
</parameter>

2) Log4NetExtentedLoggingCustomParameters.cs

namespace Common.Utils.LogHelper
{
    public class Log4NetExtentedLoggingCustomParameters
    {
        public string ExceptionCode { get; set; }

        public string Message { get; set; }

        public override string ToString()
        {
            return Message;
        }
    }
}

3) Log4NetExtentedLoggingPatternConverter.cs

namespace Common.Utils.LogHelper
{
    public class Log4NetExtentedLoggingPatternConverter : PatternConverter
    {
        protected override void Convert(TextWriter writer, object state)
        {
            if (state == null)
            {
                writer.Write(SystemInfo.NullText);
                return;
            }

            var loggingEvent = state as LoggingEvent;
            var messageObj = loggingEvent.MessageObject as Log4NetExtentedLoggingCustomParameters;

            if (messageObj == null)
            {
                writer.Write(SystemInfo.NullText);
            }
            else
            {
                switch (this.Option.ToLower()) //this.Option = "Code"
                {
                    case "code": //config conversionPattern parameter -> %exceptionCode{Code}
                        writer.Write(messageObj.ExceptionCode);
                        break;  
                    default:
                        writer.Write(SystemInfo.NullText);
                        break;
                }
            }
        }
    }
}

4) Log4NetExtentedLoggingPatternLayout.cs

namespace Common.Utils.LogHelper
{
    public class Log4NetExtentedLoggingPatternLayout : PatternLayout
    {
        public Log4NetExtentedLoggingPatternLayout()
        {
            var customConverter = new log4net.Util.ConverterInfo()
            {
                Name = "exceptionCode",
                Type = typeof(Log4NetExtentedLoggingPatternConverter)
            };

            AddConverter(customConverter);
        }
    }
}

5) Logger.cs // Enjoy your logger with new column! :)

namespace Common.Utils.LogHelper
{
    public class Logger
    {
        static ILog Logger = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        public static string LogError(string message, Exception exception = null)
        {
            var logWithErrCode = GetLogWithErrorCode(message);
            Logger.Error(logWithErrCode, exception);
            return logWithErrCode.ExceptionCode;
        }

        private static Log4NetExtentedLoggingCustomParameters GetLogWithErrorCode(string message)
        {
            var logWithErrCode = new Log4NetExtentedLoggingCustomParameters();
            logWithErrCode.ExceptionCode = GenerateErrorCode(); //this method is absent for simplicity. Use your own implementation
            logWithErrCode.Message = message;
            return logWithErrCode;
        }
    }
}

references:

http://blog.stvjam.es/2014/01/logging-custom-objects-and-fields-with

Answer 2

Three types of logging context available in Log4Net.

1. Log4Net.GlobalContext :- This context shared across all application threads and domains.If two threads set the same property on GlobalContext, One Value will override the other.

2. Log4Net.ThreadContext :- This context scope limited to calling thread. Here two threads can set same property to different values without overriding to each other.

3. Log4Net.ThreadLogicalContext :- This context behaves similarly to the ThreadContext. if you're working with a custom thread pool algorithm or hosting the CLR, you may find some use for this one.

Add the following code to your program.cs file:

static void Main( string[] args )
{
    log4net.Config.XmlConfigurator.Configure();
    log4net.ThreadContext.Properties[ "myContext" ] = "Logging from Main";
    Log.Info( "this is an info message" );
    Console.ReadLine();
}

2) Add the parameter definition for the custom column:

  <log4net>      
    <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%logger (%property{myContext}) [%level]- %message%newline" />
      </layout>
    </appender> 
  </log4net>

Answer 3

1) Modify the command text: INSERT INTO Log4Net ([Date],[Thread],[Level],[Logger],[Message],[Exception],[MyColumn]) VALUES (@log_date, @thread, @log_level, @logger, @message, @exception, @CustomColumn)

2) Add the parameter definition for the custom column:

<parameter>
   <parameterName value="@CustomColumn"/>
   <dbType value="String" />
   <size value="255" />
   <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%property{CustomColumn}" />
  </layout>
</parameter>

3) Then use one of log4net’s contexts to transfer values to the parameter:

// thread properties...
log4net.LogicalThreadContext.Properties["CustomColumn"] = "Custom value";
log.Info("Message"); 

// ...or global properties
log4net.GlobalContext.Properties["CustomColumn"] = "Custom value";