Perl: Pass on (Log4perl-)object to module

Question

I came to appreciate Log4perl and I would like to make use of it across the main Perl-script and (several) modules. How do I implement it, preferably in an OO-fashion? Is it possible to hook up the logger-object (of the main script) with the object of the module in order to fully log events that happen in the main script as well as events of the module('s object)?

Say I've got something like this main-script:

use rotate_action;
use Log::Log4perl;
my $logger = get_logger();
my $appender_log = Log::Log4perl::Appender->new(
    "Log::Dispatch::File",
    filename => "action.log",
    mode     => "append"
);
$logger->add_appender($appender_log);
$logger->info("Logger activated");

use rotate_action;
my $ro = Rotation->new; # package in rotate_action.pm
#associate logger-object with ro-object here:
$ro->$logger; # pseudo-code!

my $file "somefile";
$logger->info("processing $file");
$ro->process_file("$file");
$logger->info("finished processing $file);

And a module rotate_action like this:

{
    package Rotation;

    sub new {
        my $class = shift;
        my $self = {};
        bless $self, $class;
        return $self;
    }

    sub process_file {
        my $self = shift;
        my $file = shift;

        my $exec_string = "identify -format \"orientation: %[orientation]\ngeometry: %g\n\"";
        $exec_string .= " $file";
        my $exec_result = `$exec_string 2>&1`;
        my $err_lvl = $?;
        if ($err_lvl != 0) {
            #put same logger-object from main script here:
            $self->$logger->warn("$file is not an image");  # pseudo-code!
        } else {
            #put same logger-object from main script here:
            $self->$logger->info("rotate $file");  # pseudo-code!
            `rotate.sh $file`;
        }
    }
}

How do I pass the logger-object on to the module in order to write to the same logfile (as configured in the main-script)?

Answer 1

You can add a logger field to the object and store the logger there:

sub add_logger {
    my ($self, $logger) = @_;
    $self->{logger} = $logger;
}

Which would be called like

$ro->add_logger($logger);

And you can then

$self->{logger}->warn("$file is not an image");

Or you can provide the logger directly to the constructor.