NAME

       Log::Log4perl::Config - Log4perl configuration file syntax

DESCRIPTION

       In "Log::Log4perl", configuration files are used to describe how the system's loggers
       ought to behave.

       The format is the same as the one as used for "log4j", just with a few perl-specific
       extensions, like enabling the "Bar::Twix" syntax instead of insisting on the Java-specific
       "Bar.Twix".

       Comment lines (starting with arbitrary whitespace and a #) and blank lines (all whitespace
       or empty) are ignored.

       Also, blanks between syntactical entities are ignored, it doesn't matter if you write

           log4perl.logger.Bar.Twix=WARN,Screen

       or

           log4perl.logger.Bar.Twix = WARN, Screen

       "Log::Log4perl" will strip the blanks while parsing your input.

       Assignments need to be on a single line. However, you can break the line if you want to by
       using a continuation character at the end of the line. Instead of writing

           log4perl.appender.A1.layout=Log::Log4perl::Layout::SimpleLayout

       you can break the line at any point by putting a backslash at the very (!)  end of the
       line to be continued:

           log4perl.appender.A1.layout=\
               Log::Log4perl::Layout::SimpleLayout

       Watch out for trailing blanks after the backslash, which would prevent the line from being
       properly concatenated.

   Loggers
       Loggers are addressed by category:

           log4perl.logger.Bar.Twix      = WARN, Screen

       This sets all loggers under the "Bar::Twix" hierarchy on priority "WARN" and attaches a
       later-to-be-defined "Screen" appender to them.  Settings for the root appender (which
       doesn't have a name) can be accomplished by simply omitting the name:

           log4perl.logger = FATAL, Database, Mailer

       This sets the root appender's level to "FATAL" and also attaches the later-to-be-defined
       appenders "Database" and "Mailer" to it.

       The additivity flag of a logger is set or cleared via the "additivity" keyword:

           log4perl.additivity.Bar.Twix = 0|1

       (Note the reversed order of keyword and logger name, resulting from the dilemma that a
       logger name could end in ".additivity" according to the log4j documentation).

   Appenders and Layouts
       Appender names used in Log4perl configuration file lines need to be resolved later on, in
       order to define the appender's properties and its layout. To specify properties of an
       appender, just use the "appender" keyword after the "log4perl" intro and the appender's
       name:

               # The Bar::Twix logger and its appender
           log4perl.logger.Bar.Twix = DEBUG, A1
           log4perl.appender.A1=Log::Log4perl::Appender::File
           log4perl.appender.A1.filename=test.log
           log4perl.appender.A1.mode=append
           log4perl.appender.A1.layout=Log::Log4perl::Layout::SimpleLayout

       This sets a priority of "DEBUG" for loggers in the "Bar::Twix" hierarchy and assigns the
       "A1" appender to it, which is later on resolved to be an appender of type
       "Log::Log4perl::Appender::File", simply appending to a log file. According to the
       "Log::Log4perl::Appender::File" manpage, the "filename" parameter specifies the name of
       the log file and the "mode" parameter can be set to "append" or "write" (the former will
       append to the logfile if one with the specified name already exists while the latter would
       clobber and overwrite it).

       The order of the entries in the configuration file is not important, "Log::Log4perl" will
       read in the entire file first and try to make sense of the lines after it knows the entire
       context.

       You can very well define all loggers first and then their appenders (you could even define
       your appenders first and then your loggers, but let's not go there):

           log4perl.logger.Bar.Twix = DEBUG, A1
           log4perl.logger.Bar.Snickers = FATAL, A2

           log4perl.appender.A1=Log::Log4perl::Appender::File
           log4perl.appender.A1.filename=test.log
           log4perl.appender.A1.mode=append
           log4perl.appender.A1.layout=Log::Log4perl::Layout::SimpleLayout

           log4perl.appender.A2=Log::Log4perl::Appender::Screen
           log4perl.appender.A2.stderr=0
           log4perl.appender.A2.layout=Log::Log4perl::Layout::PatternLayout
           log4perl.appender.A2.layout.ConversionPattern = %d %m %n

       Note that you have to specify the full path to the layout class and that
       "ConversionPattern" is the keyword to specify the printf-style formatting instructions.

Configuration File Cookbook

       Here's some examples of often-used Log4perl configuration files:

   Append to STDERR
           log4perl.category.Bar.Twix      = WARN, Screen
           log4perl.appender.Screen        = Log::Log4perl::Appender::Screen
           log4perl.appender.Screen.layout = \
               Log::Log4perl::Layout::PatternLayout
           log4perl.appender.Screen.layout.ConversionPattern = %d %m %n

   Append to STDOUT
           log4perl.category.Bar.Twix      = WARN, Screen
           log4perl.appender.Screen        = Log::Log4perl::Appender::Screen
           log4perl.appender.Screen.stderr = 0
           log4perl.appender.Screen.layout = \
               Log::Log4perl::Layout::PatternLayout
           log4perl.appender.Screen.layout.ConversionPattern = %d %m %n

   Append to a log file
           log4perl.logger.Bar.Twix = DEBUG, A1
           log4perl.appender.A1=Log::Log4perl::Appender::File
           log4perl.appender.A1.filename=test.log
           log4perl.appender.A1.mode=append
           log4perl.appender.A1.layout = \
               Log::Log4perl::Layout::PatternLayout
           log4perl.appender.A1.layout.ConversionPattern = %d %m %n

       Note that you could even leave out

           log4perl.appender.A1.mode=append

       and still have the logger append to the logfile by default, although the
       "Log::Log4perl::Appender::File" module does exactly the opposite.  This is due to some
       nasty trickery "Log::Log4perl" performs behind the scenes to make sure that beginner's CGI
       applications don't clobber the log file every time they're called.

   Write a log file from scratch
       If you loathe the Log::Log4perl's append-by-default strategy, you can certainly override
       it:

           log4perl.logger.Bar.Twix = DEBUG, A1
           log4perl.appender.A1=Log::Log4perl::Appender::File
           log4perl.appender.A1.filename=test.log
           log4perl.appender.A1.mode=write
           log4perl.appender.A1.layout=Log::Log4perl::Layout::SimpleLayout

       "write" is the "mode" that has "Log::Log4perl::Appender::File" explicitly clobber the log
       file if it exists.

   Configuration files encoded in utf-8
       If your configuration file is encoded in utf-8 (which matters if you e.g. specify
       utf8-encoded appender filenames in it), then you need to tell Log4perl before running
       init():

           use Log::Log4perl::Config;
           Log::Log4perl::Config->utf( 1 );

           Log::Log4perl->init( ... );

       This makes sure Log4perl interprets utf8-encoded config files correctly.  This setting
       might become the default at some point.

SEE ALSO

       Log::Log4perl::Config::PropertyConfigurator

       Log::Log4perl::Config::DOMConfigurator

       Log::Log4perl::Config::LDAPConfigurator (coming soon!)

LICENSE

       Copyright 2002-2013 by Mike Schilli <m@perlmeister.com> and Kevin Goess <cpan@goess.org>.

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

AUTHOR

       Please contribute patches to the project on Github:

           http://github.com/mschilli/log4perl

       Send bug reports or requests for enhancements to the authors via our

       MAILING LIST (questions, bug reports, suggestions/patches):
       log4perl-devel@lists.sourceforge.net

       Authors (please contact them via the list above, not directly): Mike Schilli
       <m@perlmeister.com>, Kevin Goess <cpan@goess.org>

       Contributors (in alphabetical order): Ateeq Altaf, Cory Bennett, Jens Berthold, Jeremy
       Bopp, Hutton Davidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco, Anthony Foiani, James
       FitzGibbon, Carl Franks, Dennis Gregorovic, Andy Grundman, Paul Harrington, Alexander
       Hartmaier  David Hull, Robert Jacobson, Jason Kohles, Jeff Macdonald, Markus Peter, Brett
       Rann, Peter Rabbitson, Erik Selberg, Aaron Straup Cope, Lars Thegler, David Viner, Mac
       Yang.