Filter::Boolean(3pm) User Contributed Perl Documentation Filter::Boolean(3pm)
NAME
Log::Log4perl::Filter::Boolean - Special filter to combine the results
of others
SYNOPSIS
log4perl.logger = WARN, AppWarn, AppError
log4perl.filter.Match1 = sub { /let this through/ }
log4perl.filter.Match2 = sub { /and that, too/ }
log4perl.filter.MyBoolean = Log::Log4perl::Filter::Boolean
log4perl.filter.MyBoolean.logic = Match1 || Match2
log4perl.appender.Screen = Log::Dispatch::Screen
log4perl.appender.Screen.Filter = MyBoolean
log4perl.appender.Screen.layout = Log::Log4perl::Layout::SimpleLayout
DESCRIPTION
Sometimes, it's useful to combine the output of various filters to
arrive at a log/no log decision. While Log4j, Log4perl's mother ship,
chose to implement this feature as a filter chain, similar to Linux' IP
chains, Log4perl tries a different approach.
Typically, filter results will not need to be passed along in chains
but combined in a programmatic manner using boolean logic. "Log if this
filter says 'yes' and that filter says 'no'" is a fairly common
requirement but hard to implement as a chain.
"Log::Log4perl::Filter::Boolean" is a special predefined custom filter
for Log4perl which combines the results of other custom filters in
arbitrary ways, using boolean expressions:
log4perl.logger = WARN, AppWarn, AppError
log4perl.filter.Match1 = sub { /let this through/ }
log4perl.filter.Match2 = sub { /and that, too/ }
log4perl.filter.MyBoolean = Log::Log4perl::Filter::Boolean
log4perl.filter.MyBoolean.logic = Match1 || Match2
log4perl.appender.Screen = Log::Dispatch::Screen
log4perl.appender.Screen.Filter = MyBoolean
log4perl.appender.Screen.layout = Log::Log4perl::Layout::SimpleLayout
"Log::Log4perl::Filter::Boolean"'s boolean expressions allow for
combining different appenders by name using AND (&& or &), OR (|| or |)
and NOT (!) as logical expressions. Parentheses are used for grouping.
Precedence follows standard Perl. Here's a bunch of examples:
Match1 && !Match2 # Match1 and not Match2
!(Match1 || Match2) # Neither Match1 nor Match2
(Match1 && Match2) || Match3 # Both Match1 and Match2 or Match3
SEE ALSO
Log::Log4perl::Filter, Log::Log4perl::Filter::LevelMatch,
Log::Log4perl::Filter::LevelRange, Log::Log4perl::Filter::MDC,
Log::Log4perl::Filter::StringRange
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.
perl v5.36.0 2022-10-30 Filter::Boolean(3pm)
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