Is there a way to change to color of the message to Red?
<appender name="SmtpAppender" type="log4net.Appender.SmtpAppender">
<threshold value="INFO"/>
<to value="to#mail.com" />
<from value="from#mail.com" />
<subject value="Error in Production" />
<smtpHost value="localhost" />
<bufferSize value="512" />
<lossy value="false" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%newline%date %-5level %logger - %message%newline" />
</layout>
</appender>
I would like the mail sent will be in show in red since it simulate production issue.
The console has this error option
<mapping>
<level value="ERROR" />
<foreColor value="Red, HighIntensity" />
</mapping>
The standard smtp appender does not support this. Here is a example of a custom implementation for the smtpappeder which supports html formating:
Log4net html formatted SmtpAppender
Related
I am using Log4Net within my project, and would like to configure it so that debug/info messages go to files specific to each class, and all error messages go to a central file.
Within my application, I have several "workers". I would like each worker to have its own log file to capture debug messages. If I get a debug message that isn't captured on a specific worker, I would like it to be logged to a central debug file. I would also like to have central error logging, where all errors from any of the workers are logged in the same file.
I am having difficulty figuring out the XML configuration to do this.
Here is the closest I have come:
<log4net>
<appender name="DebugLog" type="log4net.Appender.RollingFileAppender">
<file value="logs\debug.log" />
<appendToFile value="true" />
<rollingStyle value="Date" />
<datePattern value="ddMMyyyy" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="DEBUG" />
<levelMax value="FATAL" />
</filter>
</appender>
<appender name="ErrorLog" type="log4net.Appender.RollingFileAppender">
<file value="logs\error.log" />
<appendToFile value="true" />
<rollingStyle value="Date" />
<datePattern value="ddMMyyyy" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline%stacktrace{1}%newline" />
</layout>
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="ERROR" />
<levelMax value="FATAL" />
</filter>
</appender>
<appender name="Worker1" type="log4net.Appender.RollingFileAppender">
<file value="logs\Worker1.log" />
<appendToFile value="true" />
<rollingStyle value="Composite" />
<datePattern value="ddMMyyyy" />
<maxSizeRollBackups value="100" />
<maximumFileSize value="100MB" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="DEBUG" />
<levelMax value="INFO" />
</filter>
</appender>
<appender name="Worker2" type="log4net.Appender.RollingFileAppender">
<file value="logs\Worker2.log" />
<appendToFile value="true" />
<rollingStyle value="Composite" />
<datePattern value="ddMMyyyy" />
<maxSizeRollBackups value="100" />
<maximumFileSize value="100MB" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="DEBUG" />
<levelMax value="INFO" />
</filter>
</appender>
<appender name="Worker3" type="log4net.Appender.RollingFileAppender">
<file value="logs\3.log" />
<appendToFile value="true" />
<rollingStyle value="Composite" />
<datePattern value="ddMMyyyy" />
<maxSizeRollBackups value="100" />
<maximumFileSize value="100MB" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="DEBUG" />
<levelMax value="INFO" />
</filter>
</appender>
<root>
<level value="DEBUG" />
<appender-ref ref="DebugLog" />
<appender-ref ref="ErrorLog" />
</root>
<logger name="Worker1">
<level value='DEBUG'/>
<appender-ref ref="Worker1" />
</logger>
<logger name="Worker2">
<level value='DEBUG'/>
<appender-ref ref="Worker2" />
</logger>
<logger name="Worker3">
<level value='DEBUG'/>
<appender-ref ref="Worker3" />
</logger>
</log4net>
The first issue I have is that all messages written to Worker1's class, are written to the Debug.log file, and the Worker1.log file. I don't want them written to Debug.log if they are already written to Worker1.log.
I can get around this by changing the section, by adding additivity = false. In this case, it writes to the Worker1.log, and not the Debug.log file.
However, doing this prevents errors from being written to Error.log
What happens is that if I set additivity = "false" and log an error, it gets written to Worker1.log, but does not get written to Error.log.
Is there any way to have the additivity apply to just the debug/info messages, so that I can have Debug messages in Worker1.log, Error messages in Error.log, and any debug messages that aren't specific to a logger in the debug.log file?
You are right about setting additivity="false" to isolate the debug messages to Worker1.log.
To get the error messages of Worker1 back into Error.log you also have to include the ErrorLog appender in the Worker1 logger declaration, as shown below.
<logger name="Worker1" additivity="false">
<level value='DEBUG'/>
<appender-ref ref="Worker1" />
<appender-ref ref="ErrorLog" />
</logger>
Via this setup you overrule the rules as defined in root to use a custom Worker1 Appender for debug messages and the same Error Appenderfor error messages.
Trying to understand the log4net filtering.
After reading the docs some aspects are still elusive to me.
For example I have this config file:
<?xml version="1.0" encoding="utf-8" ?>
<log4net>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="..\Logs\CurrentLog" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="10000" />
<staticLogFileName value="true" />
<filter type="log4net.Filter.LevelRangeFilter">
<acceptOnMatch value="true" />
<levelMin value="INFO" />
<levelMax value="FATAL" />
</filter>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%-5level %date [%thread] %-22.22c{1} - %m%n" />
</layout>
</appender>
<appender name="LogFileAppender" type="log4net.Appender.FileAppender">
<file value="log-file.txt" />
<appendToFile value="true" />
<layout type="log4net.Layout.PatternLayout">
<header value="Service Logging -- Start" />
<footer value="Service Logging -- End" />
<conversionPattern value="%date [%thread] %-5level %logger [%ndc]
<%property{auth}> - %message%newline" />
</layout>
</appender>
<appender name="EventLogAppender" type="log4net.Appender.EventLogAppender" >
<applicationName value="WindowsService1.exe" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger
[%property{NDC}] - %message%newline" />
</layout>
</appender>
<!-- Set the default logging level and add the active appenders -->
<root>
<level value="DEBUG" />
<appender-ref ref="LogFileAppender" />
<appender-ref ref="RollingFileAppender" />
</root>
<!-- Specify the level for specific categories (“namespace.class”)-->
<logger name="WindowsService1.MyMonitor">
<level value="WARN" />
<appender-ref ref="EventLogAppender" />
</logger>
</log4net>
My expectations were:
The RollingFileAppender has a range of [INFO:FATAL] The Root has a
Level of DEBUG so it would let DEBUG and "greater" pass. Which
means all of RollingFileAppender's range would go through.
The LogFileAppender has no range specified so it would use Root's of DEBUG or greater.
And the EventLogAppender would only send event messages of WARN or greater to the Windows Event System - and - they would only
be messages from the class "WindowsService1.MyMonitor".
However it appears that all the messaging gets filtered to the WARN level!
Including my rolling log files and the log file "log-file.txt"
This seems like it should be simple - don't know why I'm so confused by it.
Hope someone can enlighten me.
Please feel free to use crayons and pictures because I think I need them.
Thanks.
UPDATE
In my Program.cs I have:
[assembly: log4net.Config.XmlConfigurator(ConfigFile = "Log4Net.config", Watch = true)]
And in each class where logging is done:
private static readonly ILog log =
LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
UPDATE 2
At a different computer now. Had to recreate everything and used log4net debugging to assist.
But still can't get the desired output.
Basically want the WARN and above messages to go to one file and the Event logger. And those messages would be a subset of all the INFO and above messages.
The INFO and above messages - superset - would go into the rolling appender and overwrite themselves eventually. But the warnings and errors would always be maintained.
So here is a rework of all the files for a simple service. If I set WARN on the appender-ref ref=EventLogAppender then all the INFOs are suppressed.
Program.cs
[assembly: log4net.Config.XmlConfigurator(ConfigFile = "Log4Net.config", Watch = true)]
// Ref: http://www.c-sharpcorner.com/UploadFile/naresh.avari/develop-and-install-a-windows-service-in-C-Sharp/
//
// use 'sc' to install/delete the service
// run 'sc' as administrator
// sc create "MySillyService" binpath= "C:\whatever\something.exe"
// sc delete "MySillyService"
namespace SimpleService1
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
static void Main()
{
ServiceBase[] ServicesToRun;
ServicesToRun = new ServiceBase[]
{
new Service1()
};
ServiceBase.Run(ServicesToRun);
}
}
}
Service1.cs
namespace SimpleService1
{
public partial class Service1 : ServiceBase
{
private static readonly ILog log =
LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
private Timer timer1;
private int counter = 0;
public Service1()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
timer1 = new Timer();
timer1.Interval = 4000;
timer1.Elapsed += new ElapsedEventHandler(timer1_Tick);
timer1.Enabled = true;
log.Info("my service is started");
}
private void timer1_Tick(object sender, ElapsedEventArgs e)
{
counter++;
if (counter%2 == 0)
{
log.Info(String.Format("Counter({0:D}) is now even", counter));
}
else
{
log.Error(String.Format("Counter({0:D}) is now even", counter));
}
}
protected override void OnStop()
{
timer1.Enabled = false;
log.Info("my service was stopped");
}
}
}
App.config
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<appSettings>
<add key="log4net.Internal.Debug" value="true"/>
</appSettings>
<system.diagnostics>
<trace autoflush="true">
<listeners>
<add
name="textWriterTraceListener"
type="System.Diagnostics.TextWriterTraceListener"
initializeData="C:\tmp\log4net.txt" />
</listeners>
</trace>
</system.diagnostics>
</configuration>
Log4net.config
<?xml version="1.0" encoding="utf-8" ?>
<!--
Ref: http://mitch-wheat.blogspot.com/2007/04/log4net-net-logging-tool.html
I keep this config file in a separate directory and copy it with a
post-build event:
copy /Y $(SolutionDir)Logger\Log4Net.config $(TargetDir)Log4Net.config
-->
<log4net>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="..\Logs\CurrentLog" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="10000" />
<staticLogFileName value="true" />
<filter type="log4net.Filter.LevelRangeFilter">
<acceptOnMatch value="true" />
<levelMin value="INFO" />
<levelMax value="FATAL" />
</filter>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%-5level %date [%thread] %-22.22c{1} - %m%n" />
</layout>
</appender>
<appender name="LogFileAppender" type="log4net.Appender.FileAppender">
<file value="log-file.txt" />
<appendToFile value="true" />
<layout type="log4net.Layout.PatternLayout">
<header value="Service Logging -- Start - " />
<footer value="Service Logging -- End - " />
<conversionPattern value="%date [%thread] %-5level %logger [%ndc]
<%property{auth}> - %message%newline" />
</layout>
</appender>
<appender name="EventLogAppender" type="log4net.Appender.EventLogAppender" >
<applicationName value="Service1" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger
[%property{NDC}] - %message%newline" />
</layout>
</appender>
<!-- Set the default logging level and add the active appenders -->
<root>
<level value="DEBUG" />
<appender-ref ref="LogFileAppender" />
<appender-ref ref="RollingFileAppender" />
</root>
<!-- Specify the level for specific categories (�namespace.class�)-->
<logger name="SimpleService1.Service1">
<level value="WARN" />
<appender-ref ref="EventLogAppender" />
</logger>
</log4net>
Thanks for your help
Finally figured out the nuances to get this working as desired. Here's the config for anyone interested.
<?xml version="1.0" encoding="utf-8" ?>
<!--
I keep this config file in a separate directory and copy it with a
post-build event:
copy /Y $(SolutionDir)Logger\Log4Net.config $(TargetDir)Log4Net.config
-->
<log4net>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="..\Logs\CurrentLog" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="10000" />
<staticLogFileName value="true" />
<filter type="log4net.Filter.LevelRangeFilter">
<acceptOnMatch value="true" />
<levelMin value="INFO" />
<levelMax value="FATAL" />
</filter>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%-5level %date [%thread] %-22.22c{1} - %m%n" />
</layout>
</appender>
<appender name="LogFileAppender" type="log4net.Appender.FileAppender">
<file value="log-file.txt" />
<appendToFile value="true" />
<filter type="log4net.Filter.LevelRangeFilter">
<acceptOnMatch value="true" />
<levelMin value="WARN" />
<levelMax value="FATAL" />
</filter>
<layout type="log4net.Layout.PatternLayout">
<header value="Service Logging -- Start - " />
<footer value="Service Logging -- End - " />
<conversionPattern value="%date [%thread] %-5level %logger [%ndc]
<%property{auth}> - %message%newline" />
</layout>
</appender>
<appender name="EventLogAppender" type="log4net.Appender.EventLogAppender" >
<!-- Put whatever name you want to display in the event log
for 'applicationName value=XX'
-->
<applicationName value="ServiceSkippy" />
<filter type="log4net.Filter.LevelRangeFilter">
<acceptOnMatch value="true" />
<levelMin value="WARN" />
<levelMax value="FATAL" />
</filter>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger
[%property{NDC}] - %message%newline" />
</layout>
</appender>
<!-- put namespace of service application in following name -->
<logger name="ServiceWithLog4Net">
<appender-ref ref="LogFileAppender" />
<appender-ref ref="RollingFileAppender" />
<appender-ref ref="EventLogAppender" />
</logger>
</log4net>
-Skippy
Is it possible to configure log4net to have two smtp appenders - one that sends emails only when log level is >= WARN and second that sends everything, but never two on the same time.
<appender name="SmtpAppenderWarn" type="log4net.Appender.SmtpAppender">
<to value="to#domain.com" />
<from value="from#domain.com" />
<subject value="Import completed with warnings / errors" />
<smtpHost value="localhost" />
<bufferSize value="512" />
<lossy value="true" />
<evaluator type="log4net.Core.LevelEvaluator">
<threshold value="WARN"/>
</evaluator>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%newline%date [%thread] %-5level %logger [%property{NDC}] - %message%newline%newline%newline" />
</layout>
</appender>
<appender name="SmtpAppenderSuccess" type="log4net.Appender.SmtpAppender">
<to value="to#domain.com" />
<from value="from#domain.com" />
<subject value="Import completed successfully" />
<smtpHost value="localhost" />
<bufferSize value="512" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date %-5level %logger: %message%newline" />
</layout>
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="INFO" />
</filter>
</appender>
I my application I have:
Log.Info("Importer is starting...");
//my logic
//if warn Log.Warn("Warning...");
Log.Info("Import finished");
So I'm using INFO all the time. Now when I encounter WARN both messages are being sent. I wish of course that the one with success info was not sent.
I have solved the problem by overriding log4net SendBuffer method:
namespace MyProject
{
public class SmtpAppenderInfoOnly : SmtpAppender
{
protected override void SendBuffer(log4net.Core.LoggingEvent[] events)
{
foreach (var loggingEvent in events)
{
if (loggingEvent.Level != Level.Info)
return;
}
base.SendBuffer(events);
}
}
}
And then in config file:
<appender name="SmtpAppenderSuccess" type="MyProject.SmtpAppenderInfoOnly,MyDll">
That way the SendMail method will not be executed when SendBuffer is canceled.
Your appenders can have min/max values like so:
<levelMin value="INFO" />
<levelMax value="INFO" />
<levelMin value="WARN" />
<levelMax value="WARN" />
So you can use different appenders for different ranges. I believe this should work for you.
I have a WinForm that it display log information but I want it to display to only INFO level but I want the log in the log file to contain DEBUG level as well.
Below is my configuration:
<?xml version="1.0" encoding="utf-8" ?>
<!-- This section contains the log4net configuration settings -->
<log4net>
<!-- Define some output appenders -->
<appender name="LogFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="${ALLUSERSPROFILE}\\Application Data\\logs\\Gateway" />
<appendToFile value="true" />
<rollingStyle value="Date" />
<param name="StaticLogFileName" value="false" />
<datePattern value=".yyyyMMdd.lo\g" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date | [%thread] | %-5level | %logger | %message %newline" />
</layout>
</appender>
<appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
</layout>
</appender>
<appender name="ColoredConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
<mapping>
<level value="DEBUG" />
<backColor value="Blue" />
</mapping>
<mapping>
<level value="INFO" />
<backColor value="Green" />
</mapping>
<mapping>
<level value="WARN" />
<backColor value="Yellow" />
</mapping>
<mapping>
<level value="ERROR" />
<backColor value="Red" />
</mapping>
<mapping>
<level value="FATAL" />
<backColor value="Red, HighIntensity" />
</mapping>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
</appender>
<appender name="RichTextBoxAppender" type="Gateway.RichTextBoxAppender,Gateway" >
<layout type="log4net.Layout.PatternLayout">
<param name="Header" value="[Header]\r\n"/>
<param name="Footer" value="[Footer]\r\n"/>
<param name="ConversionPattern" value="%d [%t] %-5p %c [%x] - %m%n" />
</layout>
<mapping>
<level value="DEBUG" />
<textColorName value="DarkGreen" />
</mapping>
<mapping>
<level value="INFO" />
<textColorName value="ControlText" />
</mapping>
<mapping>
<level value="WARN" />
<textColorName value="Blue" />
</mapping>
<mapping>
<level value="ERROR" />
<textColorName value="Red" />
<bold value="true" />
<pointSize value="10" />
</mapping>
<mapping>
<level value="FATAL" />
<textColorName value="Black" />
<backColorName value="Red" />
<bold value="true" />
<pointSize value="12" />
<fontFamilyName value="Lucida Console" />
</mapping>
</appender>
<!-- Setup the root category, add the appenders and set the default level -->
<root>
<level value="WARN" />
<appender-ref ref="LogFileAppender" />
<appender-ref ref="ColoredConsoleAppender" />
<appender-ref ref="RichTextBoxAppender" />
</root>
<logger name ="Gateway" additivity="false">
<level value="INFO" />
<appender-ref ref="LogFileAppender" />
<appender-ref ref="ColoredConsoleAppender" />
<appender-ref ref="RichTextBoxAppender" />
</logger>
</log4net>
Right now it is set to INFO for both LogFileAppender and RichTextBoxAppender. I tried taking out the LogFileAppender in Gateway logger and move to another logger and set to "DEBUG" level for this new logger but it is still doing one or the other. How do I configure it so that the LogFileAppender has DEBUG level and RichTextBoxAppender has INFO level?
You should be able to add a filter to both of your appenders.
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="INFO" />
<levelMax value="FATAL" />
</filter>
This way one appender will only log to a certain level while the other to a different level even though they are defined by the same logger.
I agree with #gwhitake that you can use the level range filter. I also want to add, however, that you can use the LevelMatch filter if you just want to select one level. This filter allows you to add another filter at the end of it as well so that you could create a filter that had two or more levels even if they aren't next to each other in the order.
For example, the following filter will capture only DEBUG and ERROR messages (just as an example):
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="DEBUG"/>
</filter>
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="ERROR"/>
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
The one key here is that we need to have the DenyAllFilter at the end. This tells the logger that if it reaches this line, don't log it. That way it will log DEBUG messages, ERROR messages, and nothing else.
There are a lot of ways to manipulate the filter to get exactly what you want. Here is an article (full disclaimer: I wrote it) that shows you how to do a number of different things with the filter besides just level range:
http://www.codeproject.com/KB/dotnet/Log4net_Tutorial.aspx
I need to configure logger to write messages to several appenders with different Log Levels.
For ex. I want RefreshDataService to log detailed info to TransportFileAppender and Warnings and Errors to RollingFileAppender.
Also, I'm using buffering to improve logging performance.
I setup FilteredFileLog appender to forward Warnings to FileLog->RollingFileAppender.
But for RefreshDataService logger, all log messages including debug and Info getting logged to FileLog.
Can you help me to configure the RefreshDataService logger to log only Warn+ messages to FileLog? Thanks.
Below is excerpt from my log4net config.
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="${TEMP}\logs\client\${ENV}\client.log" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="4096KB" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level [%property{ENV}] [%property{UID}] %logger - %message%newline" />
</layout>
</appender>
<appender name="TransportAppender" type="log4net.Appender.RollingFileAppender">
<file value="${TEMP}\logs\client\${ENV}\client.comm.log" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="4096KB" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
</layout>
</appender>
<appender name="DetailedTransportLog" type="log4net.Appender.BufferingForwardingAppender">
<threshold value="DEBUG" />
<bufferSize value="200" />
<appender-ref ref="TransportAppender" />
</appender>
<appender name="FileLog" type="log4net.Appender.BufferingForwardingAppender">
<bufferSize value="20" />
<lossy value="false" />
<appender-ref ref="RollingFileAppender" />
</appender>
<appender name="FilteredFileLog" type="log4net.Appender.ForwardingAppender">
<threshold value="WARN" />
<appender-ref ref="FileLog" />
</appender>
<logger name="RefreshDataService" >
<level value="DEBUG" />
<appender-ref ref="FilteredFileLog" />
<appender-ref ref="DetailedTransportLog" />
</logger>
You can use a level range filter on the appender:
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="WARN" />
<levelMax value="FATAL" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
My understanding is that the Threshold property is used tell the appender to flush the buffer when messages of a certain level are logged. This way you can make for instance sure that errors are written immediately to the database.