phpMan > man > Log::Log4perl::Config(3pm)

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 and blank lines (all whitespace or empty) are ignored.

    Comment lines may start with arbitrary whitespace followed by one of:

    # - Common comment delimiter
    ! - Java .properties file comment delimiter accepted by log4j
    ; - Common .ini file comment delimiter

    Comments at the end of a line are not supported. So if you write

        log4perl.appender.A1.filename=error.log #in current dir

    you will find your messages in a file called "error.log #in current dir".

    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. Alternatively, the root logger can be addressed as
    "rootLogger":

        log4perl.rootLogger = FATAL, Database, Mailer

    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 AT perlmeister.com> and Kevin Goess <cpan AT 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 AT lists.net

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