A realistic log4net config
Most log4net config file examples show the simplest case. Here is a more realistic example of a production log4net config that uses multiple appenders. This comes from an ASP.NET application, but the same technique will work in a server or client application. This config sets up two appenders:
- The first one writes all messages at DEBUG or higher to a log file. Depending on your needs, a RollingFileAppender that creates a new file every day or week might be more appropriate.
- The second appender sends email messages when a new user account is created, or when an error is logged.
<?xml version="1.0"?>
<configuration>
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
</configSections>
<log4net>
<!-- The DebugFileAppender writes all messages to a log file-->
<appender name="DebugFileAppender" type="log4net.Appender.FileAppender">
<file value="LinkedCellsWebService.log" />
<threshold value="DEBUG" />
<appendToFile value="true" />
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="%5p [%d] - %m%n" />
</layout>
</appender>
<!-- The EmailAppender sends an email when something matches the filters-->
<appender name="EmailAppender" type="log4net.Appender.SmtpAppender">
<evaluator type="log4net.Core.LevelEvaluator">
<threshold value="DEBUG"/>
</evaluator>
<!-- The filters are processed in order:
1) match the Inserted New User message
2) match any WARN or higher messages
3) reject everything else -->
<filter type="log4net.Filter.StringMatchFilter">
<stringToMatch value="Inserted a new user" />
<acceptOnMatch value="true" />
</filter>
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="WARN" />
<acceptOnMatch value="true" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
<!-- The SmtpAppender authenticates against the mail server, the buffersize of 10 provides 10 lines
of context when an error happens. -->
<subject value="LinkedCells: Production log event" />
<to value="notifications@LinkedCells.com" />
<from value="notifications@LinkedCells.com" />
<password value ="password" />
<smtpHost value="MAILSERVER" />
<bufferSize value="10" />
<lossy value="true" />
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="%5p [%d] - %m%n" />
</layout>
</appender>
<root>
<!-- add other appenders here and the log messages will be sent to every listed appender -->
<appender-ref ref="DebugFileAppender" />
<appender-ref ref="EmailAppender" />
</root>
</log4net>
----- END OF CONFIG -----