MAN page from RedHat EL 8 perl-Log-Log4perl-1.50-1.el8.noarch.rpm


Section: User Contributed Perl Documentation (3)
Updated: 2020-07-22


Log::Log4perl::Catalyst - Log::Log4perl Catalyst Module 


In your main Catalyst application module:

  use Log::Log4perl::Catalyst;    # Either make Log4perl act like the Catalyst default logger:  __PACKAGE__->log(Log::Log4perl::Catalyst->new());    # or use a Log4perl configuration file, utilizing the full     # functionality of Log4perl  __PACKAGE__->log(Log::Log4perl::Catalyst->new('l4p.conf'));

... and then sprinkle logging statements all over any code executedby Catalyst:

    $c->log->debug("This is using log4perl!");


This module provides Log4perl functions to Catalyst applications. It wasinspired by Catalyst::Log::Log4perl on CPAN, but has been completely rewritten and uses a different approach to unite Catalyst and Log4perl.

Log4perl provides loggers, usually associated with the currentpackage, which can then be remote-controlled by a centralconfiguration. This means that if you have a controller function like

    package MyApp::Controller::User;    sub add : Chained('base'): PathPart('add'): Args(0) {        my ( $self, $c ) = @_;        $c->log->info("Adding a user");        # ...    }

Level-based control is available via the following methods:

   $c->log->debug("Reading configuration");   $c->log->info("Adding a user");   $c->log->warn("Can't read configuration ($!)");   $c->log->error("Can't add user ", $user);   $c->log->fatal("Database down, aborting request");

But that's not all, Log4perl is much more powerful.

The logging statement can be suppressed or activated based on a Log4perlfile that looks like

      # All MyApp loggers opened up for DEBUG and above    log4perl.logger.MyApp = DEBUG, Screen    # ...


      # All loggers block messages below INFO    log4perl.logger=INFO, Screen    # ...

respectively. See the Log4perl manpage on how to perform fine-grained log-level and location filtering, and how to forward messages not onlyto the screen or to log files, but also to databases, email appenders,and much more.

Also, you can change the message layout. For example if you wantto know where a particular statement was logged, turn on file names and line numbers:

    # Log4perl configuration file    # ...    log4perl.appender.Screen.layout.ConversionPattern = \          %F{1}-%L: %p %m%n

Messages will then look like INFO Saving user profile for user "wonko"

Or want to log a request's IP address with every log statement? No problem with Log4perl, just call

    Log::Log4perl::MDC->put( "ip", $c->req->address() );

at the beginning of the request cycle and use

    # Log4perl configuration file    # ...    log4perl.appender.Screen.layout.ConversionPattern = \          [%d]-%X{ip} %F{1}-%L: %p %m%n

as a Log4perl layout. Messages will look like

    [2010/02/22 23:25:55]- INFO Reading profile for user "wonko"

Again, check the Log4perl manual page, there's a plethora of configurationoptions. 


new($config, [%options])
If called without parameters, new() initializes Log4perl in a way so that messages are logged similarly to Catalyst's default loggingmechanism. If you provide a configuration, either the name of a configurationfile or a reference to a scalar string containing the configuration, itwill call Log4perl with these parameters.

The second (optional) parameter is a list of key/value pairs:

  'autoflush'   =>  1   # Log without buffering ('abort' not supported)  'watch_delay' => 30   # If set, use L<Log::Log4perl>'s init_and_watch
Flushes the cache.
Clears the logging system's internal buffers without logging anything.

Using :easy Macros with Catalyst

If you're tired of typing


and would prefer to use Log4perl's convenient :easy mode macros like

    DEBUG "...";

then just pull those macros in via Log::Log4perl's :easy mode and startcranking:

    use Log::Log4perl qw(:easy);      # ... use macros later on    sub base :Chained('/') :PathPart('apples') :CaptureArgs(0) {        my ( $self, $c ) = @_;        DEBUG "Handling apples";    }

Note the difference between Log4perl's initialization in Catalyst, whichuses the Catalyst-specific Log::Log4perl::Catalyst module (top of thispage), and making use of Log4perl's loggers with the standard Log::Log4perl loggers and macros. While initialization requires Log4perlto perform dark magic to conform to Catalyst's different logging strategy,obtaining Log4perl's logger objects or calling its macros are unchanged.

Instead of using Catalyst's way of referencing the ``context'' object $c to obtain logger references via its log() method, you can just as well use Log4perl's get_logger() or macros to access Log4perl's logger singletons. The result is the same. 


Copyright 2002-2013 by Mike Schilli <> and Kevin Goess <>.

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


Please contribute patches to the project on Github:

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

MAILING LIST (questions, bug reports, suggestions/patches):

Authors (please contact them via the list above, not directly):Mike Schilli <>,Kevin Goess <>

Contributors (in alphabetical order):Ateeq Altaf, Cory Bennett, Jens Berthold, Jeremy Bopp, HuttonDavidson, Chris R. Donnelly, Matisse Enzer, Hugh Esco, AnthonyFoiani, James FitzGibbon, Carl Franks, Dennis Gregorovic, AndyGrundman, 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.



Using :easy Macros with Catalyst

This document was created byman2html,using the manual pages.