phpman > perldoc > Log::Log4perl::Catalyst(3pm)

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

SYNOPSIS
    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 executed by Catalyst:

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

DESCRIPTION
    This module provides Log4perl functions to Catalyst applications. It was inspired 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 current package, which can then be
    remote-controlled by a central configuration. 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 Log4perl file that looks like

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

    or

          # 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 only to 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 want to 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

        MyApp.pm-1869: 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]-123.122.108.10 MyApp.pm-1953: INFO Reading profile for user "wonko"

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

METHODS
    new($config, [%options])
        If called without parameters, new() initializes Log4perl in a way so that messages are
        logged similarly to Catalyst's default logging mechanism. If you provide a configuration,
        either the name of a configuration file or a reference to a scalar string containing the
        configuration, it will 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

    _flush()
        Flushes the cache.

    abort($abort)
        Clears the logging system's internal buffers without logging anything.

  Using :easy Macros with Catalyst
    If you're tired of typing

        $c->log->debug("...");

    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 start cranking:

        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, which uses the
    Catalyst-specific Log::Log4perl::Catalyst module (top of this page), and making use of
    Log4perl's loggers with the standard Log::Log4perl loggers and macros. While initialization
    requires Log4perl to 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.

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.