Catalyst(3) User Contributed Perl Documentation Catalyst(3)NAMELog::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 sprinkly 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 no 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 vary the layout of each message. 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 similiarly to Catalyst's default
logging mechanism. If you provide configuration, either the name of
a configuration file or a reference to 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.
COPYRIGHT AND LICENSE
Copyright 2002-2010 by Mike Schilli <m@perlmeister.com>
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.14.1 2011-05-02 Catalyst(3)
