trying to extend Log::Log4perl

[mifflin]

I'm trying to extend Log::Log4perl so that I can trap all messages for a process and, at the end, format them all nicely in an email. The example I have below only deals with error messages to more simply demonstrate my issue.

I'm using perl 5.8.2 and Log::Log4perl 1.22

Here is my logger package:

package Mylogger;

use warnings;
use strict;

use base qw(Log::Log4perl);

my @error_msgs;

sub init {
    Log::Log4perl::init(@_);
    return;
}

sub get_logger {
    $Log::Log4perl::caller_depth = 1;
    my $logger = Log::Log4perl::get_logger(@_);
    bless $logger, __PACKAGE__;
    return $logger;
}

sub error {
    my ($this, $msg) = @_;
    push(@error_msgs, "ERROR $msg");
    $this->SUPER::error($msg);
    return;
}

sub get_logged_errors {
    return \@error_msgs;
}

1;

Here is my test program:

use strict;
use warnings;
use FindBin;
use Mylogger;

my $conf = q(
    log4perl.rootLogger=DEBUG, Screen
    log4perl.appender.Screen         = Log::Log4perl::Appender::Screen
    log4perl.appender.Screen.stderr  = 0
    log4perl.appender.Screen.layout=PatternLayout
    log4perl.appender.Screen.layout.ConversionPattern=%d{ISO8601} %-5p
+ %C %m%n
);

Mylogger::init(\$conf);

my $log = Mylogger::get_logger();

$log->error('error 1');
$log->error('error 2');

Here is a run of my test program showing two errors:

#test.pl
Can't locate object method "error" via package "Mylogger" at Mylogger.
+pm line 25.
Can't locate object method "DESTROY" via package "Mylogger" at /usr/op
+t/perl5/lib/site_perl/5.8.2/Log/Log4perl/Logger.pm line 60.
END failed--call queue aborted.

The error on line 25 in MyLogger is the call the SUPER::error, which somehow cannot be found. Also there is some issue with the way I'm implementing this which causes Log4perl to not find a DESTROY method. What am I missing here?

[ikegami]

I'm not knowledged in the use of Log::Log4perl, but it seems to me that the way to go is to create a new appender.

Going that route also provides lots of code on which you can base your own.

[mifflin]

There is Log::Dispatch::Email but my problem is that it does not appear to give me enough control of the email which needs to contain more that just what I am logging.

[Anonymous Monk]

How can I configure Log::Log4perl to send me email if something happens?

log4perl.rootLogger = DEBUG, Screen, Mailer
log4perl.appender.Mailer         = Log::Dispatch::Email::MailSend
log4perl.appender.Mailer.to      = [e-mail]
log4perl.appender.Mailer.subject = Something's broken!
log4perl.appender.Mailer.layout  = SimpleLayout
log4perl.appender.Mailer.buffered = 0
...

[Bloodnok]

Hi ,
It's a bit late I know buuuut....I'm going to do this anyway:-)

Having encountered a not unrelated problem myself, I did a little investigating and AFAICT, L4P appears to construct it's methods dynamically (using closures) and doesn't make them available to an inheriting bespoke logger wrapper package via the standard route e.g. @ISA/SUPER:: etc., so they are available only to the L4P instance itself.

The only 'obvious' way I could think of at the time was to utilise MyWrapper::AUTOLOAD to dispatch non-overridden L4P method calls to the logger object via a get_logger(class) call and let L4P deal with unknown methods etc. e.g. in a manner something similar to ...

package MyWrapper;
use warnings;
use strict;
use autodie; # Not strictly necessary, but JIC I forget later

use base qw/Log::Log4perl;
our $AUTOLOAD;

sub get_logger {
    my $self = shift;

    return Log::Log4perl->get_logger(@_); # or $self->SUPER::get_logge
+r(@_) but that requires
                                          # sufficient knowledge of L4
+P to know/realise that
                                          # get_logger is a standard e
+xportable function
}

sub trace_beg {
    my $self = shift;
    
    __PACKAGE__->debug("Starting with args: " . join ' ', @_);
}

sub AUTOLOAD {
    my $self = shift;
    (my $method = $AUTOLOAD) =~ s,.*::,,;
    
    my $class = caller;
    local $Log::Log4perl::Caller_depth = $Log::Log4perl::caller_depth 
++ 1;
    goto $self->get_logger($class)->$method(@_);
}

1;

The usual caveat emptor applies, but that's close to the way I managed to do it - less an awful lot of extraneous code.

Hope that helps ...