In my application I have a separate file appender for Errors and (Info and Debug). In production I just want to log the errors and disable the information and debug logs. Will keeping the appenders good way to do it, considering the performance in mind, or will it be bad for performance
Keep the appenders but change the log level value to WARN inside the "root" tag
<level value="WARN" />
<appender-ref ref="FILE.ERROR" />
<appender-ref ref="FILE.INFO" />
Comment out the information appender from the "root" tag
<level value="WARN" />
<appender-ref ref="FILE.ERROR" />
<!--<appender-ref ref="FILE.INFO" />-->
My logic says #2 is better because if we keep it enabled (as in #1) Log4net will initialize the appender, then for every log statement it will then compare the log level from the log statement vs the log level allowed by the appender and then take decision to log it or not. By using#2 we can avoid this loop and extra execution as the information appender will not be initialized at all.
My information appender has log level set as
<filter type="log4net.Filter.LevelRangeFilter">
<levelMin value="DEBUG" />
<levelMax value="INFO" />
</filter>
My question is my understanding from performance point of view valid? Or, it doesn't really matter for log4net, or may be log4net will not initialize the information appender as its log level does not match the root logger level viz. WARN
Related
I have an app where sometimes I'd like to log in Debug mode. Unfortunately i link with a third party lib that I can't rebuild. It was built to use log4net and on the Debug mode it is very verbose.
I don't want to get any notifications from that library. I do however want to get log notifications from all other code that wants to write.
Is there a way to exclude a namespace or library from logging when using either the SMTPAppender or RollingFile Appender writers?
You could use a filter, e.g.
<filter type="log4net.Filter.LoggerMatchFilter">
<!-- allows this sub-namespace to be logged... -->
<loggerToMatch value="Noisy.Namespace.But.Important" />
</filter>
<filter type="log4net.Filter.LoggerMatchFilter">
<!-- ...but not the rest of it -->
<loggerToMatch value="Noisy.Namespace" />
<acceptOnMatch value="false" />
</filter>
More details from this article.
Im imagine that you are using a configuration where you set only the root level of your logging infrastructure:
<root>
<level value="DEBUG" />
<appender-ref ref="A1" />
</root>
However it is possible to define other levels of logging using the logger names. If you or the third party app followed standard practices, your loggers are named after the class they live with its namespace, so you will have loggers called
MyApp.Main
MyApp.Business
MyApp.Business.Messages
ThirdParty.API
etc...
What you can do in this case is declare the logging at the namespace level you're interested in. For example to log only what lives under MyApp.Main add the following
<logger name="MyApp.Main">
<level value="DEBUG" />
<appender-ref ref="A1" />
</logger>
and remove any appender from the root level. Then you only log the loggers that live under the MyApp name. See the documentation for more info.
If you are unlucky and the loggers don't conform to this hierarchy, you can still filter them out by using a LoggerMatchFilter in your appender; this lets you either define what logger can pass, or what loggers cannot. There are lots of filters, feel free to explore them
pardon if the question is too trivial. I am completely new to log4j. I have seen that there are two tags and tags, which refer to various appenders.
Say i want to log the information in my code base in a file, send it to my email and print it to console. I want the level set to info. Isnt it enough to have a single tag which has references to the three appenders ?( file, email and the console) why do we need another for the same ?
It is enough.
In log4j a logger is associated with a package or sometimes with a particular class. Package/class of a logger is defined by the attribute "name". A logger logs messages in its package and also in all the child packages and their classes. The only exception is the root logger that logs messages for the all classes in the application.
A logger also has level and may have one or many appenders (logging destinations) attached to it.
In the next example we have two loggers:
the root logger that logs messages with level INFO or above in the all packages to the various destinations: console, e-mail and file,
"com.foo" logger that logs messages with level WARN or above in package "com.foo" and its child packages to the another file.
<log4j:configuration>
<!-- Declaration of appenders FILE, MAIL, CONSOLE and ANOTHERFILE -->
...
<!-- -->
<logger name="com.foo">
<level value="warn"/>
<appender-ref ref="ANOTHERFILE" />
</logger>
<root>
<priority value ="info" />
<appender-ref ref="FILE" />
<appender-ref ref="MAIL" />
<appender-ref ref="CONSOLE" />
</root>
</log4j:configuration>
You should read more about the log4j basics.
My Application is using logging in two manner....1) programatic 2) log4j.xml
I have to create the logs files in two ( 1 using programatic and other using log4j.xml ) locations.
Programatic way ( have one more properties file in which all the things are mention like log level and all....lets say..thorugh this...file is getting created..name as "SAS_VP.log") :
Enumeration loggers = Logger.getRootLogger().getLoggerRepository().getCurrentLoggers();
......
Logger temp = (Logger)iter.next();
temp.setLevel(level);
log4j.xml
<appender name="FILE" class="org.apache.log4j.RollingFileAppender">
<param name="File" value="/LOGS/SAM/SAM_VJ.log"/>
<param name="Threshold" value="DEBUG"/>
<param name="MaxFileSize" value="10000KB"/>
<param name="MaxBackupIndex" value="10"/>
<param name="Append" value="false"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d{dd MMM yyyy HH:mm:ss,SSS} [%t] %5p [%F(% M):%L] %m%n"/>
</layout>
</appender>
<root>
<appender-ref ref="CONSOLE"/>
<appender-ref ref="FILE"/>
</root>
ISSUE :
Log level which i set programatically overwrite the log level of log4j.xml.Like in log4j.xml is have set the level "Debug" and Programatically I have set the level as "ERROR" then the file (SAM_VJ.log) which is created by log4j.xml only contains ERROR level logs.
How to solve this issue...I want that...my both logging ( programmatic and log4j ) should be indepedent.
Is there anything in log4j in which...if i have set the log level of package "com.sas" is "Debug" then nobody can modify that...something like mutable type
<logger name="com.sam">
<priority value="DEBUG"/>
</logger>
Looking for your suggesstion....
I'm not sure you should really ask for such a functionality.
You're talking about a way to configure the log4j framework, and yes, it supports 3 different ways of configuration:
properties file
xml configuration
programmatically, via your java code
Its ok to me that the programmatic configuration allows to change the configured state of log4j loggers/appenders whatsoever.
Your xml configuration should be loaded during the system startup, and then you apply your java code that overrides the configuration.
If you have a logic of supplying a configuration in Java, why don't you improve your logic and define an error level (from your example) only if you really wish to do it.
Its impossible to configure the same logger to work both with DEBUG level (and up) AND ERROR level (and up).
This is a feature in fact, and not a drawback, since it allows to change the behavior of LOG4j on the running system (without a restart) which is useful for issue tracking.
Of course you can WRAP your loggers so that they won't allow setLevel, but, I really don't see why would you do that.
Hope, this helps
Why not just use two appenders with different log levels instead?You can add levelMax and levelMin params to tell log4j the appender just log those levels.
<param name="LevelMax" value="warn" />
<param name="LevelMin" value="info" />
I am confused as to why INFO statements are making it to the Console. Here is the general setup:
<appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
<param name="Target" value="System.out"/>
<param name="Threshold" value="DEBUG"/>
<layout .../>
</appender>
<appender name="REST_LOG" class="org.apache.log4j.DailyRollingFileAppender">
<param name="File" value="/logs/rest.log" />
<param name="Threshold" value="INFO" />
....
</appender>
<category name="xyz.web">
<priority value="WARN" />
<appender-ref ref="CONSOLE" />
</category>
<category name="xyz.web.rest">
<priority value="INFO" />
<appender-ref ref="REST_LOG" />
</category>
So I want INFO and above statements to only do to REST_LOG and WARN statements and above to go to REST_LOG and CONSOLE. What I am seeing is INFO statements from xyz.web.rest in the REST_LOG as expected but also seeing INFO statements from xyz.web.rest in CONSOLE which I wasn't expecting.
Can somebody explain what is going on?
You should set additivity to false on the xyz.web.rest logger.
Without the additivity you will see all the INFO message logged with logger xyz.web.rest twice in the console, because the logger inherit the appender of Root logger
and of the xyz.web logger.
See the Appenders and Layouts section of the Log4j documentation
Named Hierarchy
A logger is said to be an ancestor of another logger
if its name followed by a dot is a prefix of the descendant logger
name. A logger is said to be a parent of a child logger if there are
no ancestors between itself and the descendant logger.
For example, the logger named "com.foo" is a parent of the logger
named "com.foo.Bar". Similarly, "java" is a parent of "java.util" and
an ancestor of "java.util.Vector". This naming scheme should be
familiar to most developers.
The root logger resides at the top of the logger hierarchy. It is exceptional in two ways:
it always exists,
it cannot be retrieved by name.
Appenders and Layouts
Each enabled logging request for a given logger will be forwarded to
all the appenders in that logger as well as the appenders higher in
the hierarchy. For example, if a console appender is added to the
root logger, then all enabled logging requests will at least print on
the console.
If in addition a file appender is added to a logger, say C, then
enabled logging requests for C and C's children will print on a file
and on the console. It is possible to override this default behavior
so that appender accumulation is no longer additive by setting the
additivity flag to false.
The thresholds are hierarchical. DEBUG includes all INFO, WARN, ERROR. So it is natural that if you define console with a threshold of DEBUG that it would receive INFO level messages.
If you only want console to receive WARN and ERROR, set its threshold to WARN.
I'm writing a simple test project to experiment with log4net and I've hit a wall right off the bat. No matter what I do in my config file, the my logger is initialized with all "IsXXXXEnabled" flags set to false. Here is my very simple app.config:
<log4netgroup>
<log4net xsi:noNamespaceSchemaLocation="http://csharptest.net/downloads/schema/log4net.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<appender name="EventLogAppender" type="log4net.Appender.EventLogAppender">
<param name="LogName" value="Application" />
<param name="ApplicationName" value="HelloProgram" />
<threshold value="DEBUG"/>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%logger - %newline%message" />
</layout>
</appender>
<root>
<level value="DEBUG" />
<appender-ref ref="EventLogAppender" />
</root>
<logger name="HelloLogger">
<level value="DEBUG" />
<appender-ref ref="EventLogAppender" />
</logger>
</log4net>
</log4netgroup>
Here is the trivial test in Main:
ILog Log = LogManager.GetLogger("HelloLogger");
if(Log.IsErrorEnabled)
Console.WriteLine("The logger is working!");
else
Console.WriteLine("Nope");
The output is "Nope". I tried switching the threshold and level values to "ALL", but nothing changed. This seems so simple, what am I missing to enable everything?
Thanks
Fixed it! I don't know why this call is not mentioned in the log4net manual or why I specifically need it, but adding this assembly to my project enabled all log levels:
[assembly:XmlConfigurator(Watch = true)]
Found here:
How do I configure log4net so that log.IsDebugEnabled is true?
You should configure the root logger:
<root>
<level value="DEBUG" />
<appender-ref ref="EventLogAppender" />
</root>
Any non-root loggers (the ones you create with <logger name="...">) apply only to classes whose namespace-qualified name has the logger name as a prefix. So the logger you have created will only apply to a classes that is outside of a namespace and whose name is HelloLogger, or to any classes residing in a namespace called HelloLogger (and possibly within namespaces nested inside that one). (When I say that a logger "applies to" a class X, I mean that that that's the logger you will get when you call LogManager.GetLogger(typeof(X)).)
Edit: You also need to call log4net.Config.XmlConfigurator.Configure(); in order to get log4net to read App.config. Also, delete the outermost <log4netgroup> element and rename the config section name: <section name="log4net" .../>.
Configuring the root logger is not strictly necessary, but the argument of Aasmund is certainly valid. I think the problem is that you try to use the EventLogAppender. For simple tests you should use the ConsoleAppender as this is probably the simplest appender that you can make work in a console application.
The EventLogAppender requires some additional steps to setup: You need to create an event source and that requires administrative rights. The Appender attempts to do this on the fly, but it usually fails silently if UAC is turned on. To see if that is a problem you can try to turn on internal debugging.
Usually you would create an event source with an installation program.
If you are using a separate configuration file for log4net, do this: after following all the other setup instructions, make sure that u right click on the file in the visual studio solution explorer, select properties, expand the "Advanced" option group, set the "Copy To Output Directory" value as "Copy always". That will do the magic... :) cheers!!