How to enable and disable log4Net log levels? - log4net

I am trying to setup the log4net configuration in my Dot Net Core C# library. I have configured the following log levels. But I want to enable and disable the log levels independently.
<root>
<level value="Info" />
<level value="Warn" />
<level value="Error" />
<level value="Fatal" />
<level value="Debug" />
<appender-ref ref="LogFileAppender" />
</root>
For example, how can I disable and enable the Debug flag by setting it to true or false?
Something like
<level value="Debug" Enable = "True"/>
I think there is some settings, but I don't remember. Thanks for your help to fix this issue.

But I want to enable and disable the log levels independently.
You can't.
The levels are not independent but ordered as follows
ALL
DEBUG
INFO
WARN
ERROR
FATAL
OFF
So when you set your logging level you automatically include messages for that level and all lower levels.
E.g. If you set your level to Debug you also get Info,Warn, Error and Fatal messages and if your set your level to Info, you also get Warn, Error and Fatal messages etc

You'll have to apply a LevelMatchFilter on the appender, which filters on the exact match of the specified level. You can combine multiple filters in case you want to log more than 1 specific level.
Note that you have to end with a DenyAllFilter to block the other levels.
An example, given these log statements
logger.Debug("Debug");
logger.Info("Info");
logger.Warn("Warn");
logger.Error("Error");
logger.Fatal("Fatal");
When you apply the configuration below, only the message Debug will be logged.
<log4net>
<appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="DEBUG" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%message%newline" />
</layout>
</appender>
<root>
<appender-ref ref="ConsoleAppender" />
</root>
</log4net>
When you want to log 2 levels, e.g. only error and info, then you combine the filters as shown here.
The log output will be Info and Error.
<log4net>
<appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="ERROR" />
</filter>
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="INFO" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%message%newline" />
</layout>
</appender>
<root>
<appender-ref ref="ConsoleAppender" />
</root>
</log4net>

Related

What's wrong with my log4net config file

I have a config file with two appenders, one file appender and one database appender. I want to log everything to the file appender, and only log exceptions to the database appender. When setting up both appenders in the section it logs fine but all log events are sent to both appenders, which is not what i want.
I changed the configuration but with this current configuration, exceptions get logged to the database, and nothing is getting written to the file appender. Can anyone tell me why I am not getting anything written to the file appender?
<log4net debug="true">
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="C:\Log4net\Workflow\TestLog.txt" />
<threshold value="All" />
<appendToFile value="true" />
<rollingStyle value="Size" />
<maxSizeRollBackups value="10" />
<maximumFileSize value="10KB" />
<staticLogFileName value="true" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%-5p {%logger} %d %5rms %-22.22c{1} %-18.18M - %m%n" />
</layout>
</appender>
<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
<!-- Removed to keep this snippet simple-->
</appender>
<root>
<level value="Error" />
<appender-ref ref="AdoNetAppender" />
</root>
<logger name="AllLogs">
<level value="ALL" />
<appender-ref ref="RollingLogFileAppender" />
</logger>
</log4net>
What you have here is the following:
all logs events with the level Error or more will go to the AdoNetAppender
all logs events originating from a logger whose name is based on AllLogs will go to the RollingLogFileAppender
From what I understand you want all logs to default to the file, and only error ones to go also to the database. Then simply add both appenders to your root logger so that both get all events, and add filters to only let filters you're interested in pass through: a level range filter on your database appender would work
<log4net debug="true">
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<!-- rest of config snipped to save space -->
</appender>
<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="ERROR" />
<levelMax value="FATAL" />
</filter>
<!-- rest of config snipped to save space -->
</appender>
<root>
<appender-ref ref="AdoNetAppender" />
<appender-ref ref="RollingLogFileAppender" />
</root>
</log4net>
Of course if you don't want any duplicate just filter errors and above in the rolling file appender

Different levels of logging with log4net

I must log some methods. In one method I must log everything. In all others method I've just log exception...
I have done this configuration:
<log4net>
<appender name="OneMethodFileAppender" type="log4net.Appender.RollingFileAppender">
...
<filter type="log4net.Filter.PropertyFilter">
<key value="realMethod" />
<stringToMatch value="xxx" />
<acceptOnMatch value="true" />
</filter>
</appender>
<appender name="WebsiteFileAppender" type="log4net.Appender.RollingFileAppender">
...
<filter type="log4net.Filter.PropertyFilter">
<key value="realMethod" />
<stringToMatch value="xxx" />
<acceptOnMatch value="false" />
</filter>
</appender>
<root>
<appender-ref ref="WebsiteFileAppender">
<threshold value="ERROR" />
</appender-ref>
<appender-ref ref="OneMethodFileAppender">
<threshold value="INFO" />
</appender-ref>
</root>
</log4net>
So, when I match the property realMethod I should use the appender OneMethodFileAppender that log at the INFO level; in all other cases i should use the appender WebsiteFileAppender that log at ERROR level.
I have a different output.
1. When i match the method xxx everything works correctly. I mean that a log at INFO level in the correct log.
2. But when I do not match the method xxx, I log in both files and both at INFO level.
I would suggest to use the logger element to configure your logging:
<log4net>
<appender name="OneMethodFileAppender" type="log4net.Appender.RollingFileAppender">
...
</appender>
<appender name="WebsiteFileAppender" type="log4net.Appender.RollingFileAppender">
...
</appender>
<root>
<appender-ref ref="WebsiteFileAppender">
<threshold value="ERROR" />
</appender-ref>
</root>
<logger name="LoggerName1">
<level value="INFO" />
<appender-ref ref="WebsiteFileAppender" />
</logger>
<logger name="LoggerName2">
<level value="INFO" />
<appender-ref ref="OneMethodFileAppender" />
</logger>
</log4net>
Both methods should have there own logger:
logger = LogManager.GetLogger("logger1");

Log4Net filter out INFO from the log and only show DEBUG & ERROR

Is there any way to filter out INFO from the log and only show DEBUG & ERROR, using the config in web.config ?
<root>
<level value="DEBUG" />
<appender-ref ref="ColoredConsoleAppender" />
<appender-ref ref="RollingFileSystemAppender" />
<appender-ref ref="ConsoleAppender" />
</root>
In log4X there are filters that can be applied to appenders in order to filter messages; here is a list of the filters
log4net.Filter.LevelMatchFilter Filters log events that match a specific logging level; alternatively this can be configured to filter events that DO NOT match a specific logging level.
log4net.Filter.LevelRangeFilter Similar to the LevelMatchFilter, except that instead of filtering a single log level, this filters on an inclusive range of contiguous levels.
log4net.Filter.LoggerMatchFilter Filters log events based on the name of the logger object from which they are emitted.
log4net.Filter.StringMatchFilter Filters log events based on a string or regular expression match against the log message.
log4net.Filter.PropertyFilter Filters log events based on a value or regular expression match against a specific context property.
log4net.Filter.DenyAllFilter Effectively drops all logging events for the appender.
In your case you would need to filter your three appenders in order to exclude the INFO level: a LevelMatchFilter refusing INFO level logs would work:
<filter type="log4net.Filter.LevelMatchFilter">
<acceptOnMatch value="false" />
<levelToMatch value="INFO" />
</filter>
Note that the <filter> tags (as shown in the examples above) must appear within an <appender> tag! For example (this is not a valid log4net configuration--I'm only showing how the <filter> tag is a child entry under <appender>:
<configuration>
<configSections>
<section ...="" />
</configSections>
<startup>
<supportedRuntime ...="" />
</startup>
<log4net>
<appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date{dd MMM yyyy HH:mm:ss} {%thread} %level - %message%newline%exception"/>
</layout>
<filter type="log4net.Filter.LevelMatchFilter">
<acceptOnMatch value="true" />
<levelToMatch value="INFO" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
</appender>
<root>
<appender-ref ...="" />
</root>
<logger name="Log4NetTest.OtherClass">
<level value="DEBUG"/>
<appender-ref ref="ConsoleAppender"/>
</logger>
</log4net>
</configuration>

Exiting the logging from an appender

Is it possible to configure so that log4net stops going through the rest of the appenders if an appender got a match?
Something like:
<appender name="TlsReadingAppender" type="log4net.Appender.RollingFileAppender">
<file value="C:\logs\TPOSIn_TlsReading.log" />
<filter type="log4net.Filter.LoggerMatchFilter">
<loggerToMatch value="TPOSIn.ServiceApp.Tls.TlsHandler"/>
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
<dontCheckAnyMoreAppenders />
</appender>
You can specify a very long list of appenders but they will only be "Active" if they are referenced in the root tag of your log4net.config file:
<root>
<level value="ERROR" />
<appender-ref ref="fileLogAppender" />
</root>
You could create a list of appenders, using "namespace.class" as the name of the appender to filter the events on each file.
Can you share a bit more about your requirements and what you want to achieve?

EventLogAppender - How to stop errors being logged into application Event log

I am using log4net – EventLogAppender to log the application errors to a custom log. This happens, but the errors are also logged in Application log. Since I have my own custom event log say myLog, is it possible to stop the errors being logged into default log Application?
<log4net debug="true">
<appender name="sendAlertAppender" type="sendAlertAppender.MultiThresholdNotifyingAppender,sendAlertAppender">
<LevelThreshold value="ERROR"/>
<appender-ref ref="EventLogAppender"/>
</appender>
<appender name="EventLogAppender" type="log4net.Appender.EventLogAppender">
<param name="LogName" value="xxxWebLogs" />
<param name="ApplicationName" value="xxx" />
<eventId value="5" />
<eventCategory value="10" />
<filter type="log4net.Filter.LevelRangeFilter">
<acceptOnMatch value="true" />
<levelMin value="INFO" />
<levelMax value="FATAL" />
</filter>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
</layout>
</appender>
<root>
<level value="ALL"/>
<priority value="DEBUG" />
<appender-ref ref="sendAlertAppender"/>
<appender-ref ref="EventLogAppender"/>
</root>
</log4net>
I'm still not sure what your issue is, but looking at the configuration I believe you need to change the LogName setting:
<param name="LogName" value="PortalWebLogs" />
If this doesn't work, it could be a permissions issue. See here for more information:
log4Net EventlogAppender does not work for Asp.Net 2.0 WebSite?
I haven't done much with using the event log appender, so i'm not really sure. here's another question talking about it and in the answer, it shows using a logName element with a value attribute instead of a param element. might be worth trying that.
Configuring a custom event log for log4net

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