in reply to Can I from within a module access variables from the calling program?

Q: What if I need dynamic values in a static Log4perl configuration file?

A: log4perl.appender.Logfile.filename = sub { logfile(); };

A: log4perl.appender.Logfile.filename = sub { MyHackySack->logfile(); };

A: log4perl.appender.Logfile.filename = sub { $Hallo::Ween::GLOBULON || 'punkinguts.log' };

  • Comment on Re: Can I from within a module access variables from the calling program?

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Re^2: Can I from within a module access variables from the calling program?
by Anonymous Monk on Oct 29, 2012 at 09:49 UTC

    Also heed the security warning in the FAQ item I linked above, and circumvent the security issue with a custom appender like (the untested): 

    package Log::Log4perl::Appender::HJOfilnamed;
use parent qw[ Log::Log4perl::Appender::File ];
use POSIX();
sub new {
    my $class = shift;
    my %opts  = @_;
    my $tim   = POSIX::strftime('%Y-%m-%dT%H-%M-%SZ', gmtime);
    my $fname = join '.', grep defined, $opts{name}, $opts{appender}, 
+$tim, 'log';
    $fname =~ s{::}{.}g;
    $fname =~ s{[^0-9a-zA-Z\-\+\.}{}g;
    $fname = $1 if $fname =~ /^(.*)$/
    return $class->new( @_, filename => $fname );
}

    [download]
    So  log4perl.appender.myFILE = Log::Log4perl::Appender::HJOfilnamed gets you a  MyApp.myFILE.2012-10-29T02-40-04Z.log

    You'd probably want to set other defaults to your liking :)( layout, mode, ... )

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      Hi Anonymous Monk,

      Thank you for your answer, it seems to fix my issue, but I'm afraid I don't understand it quite well :(

      package Log::Log4perl::Appender::HJOfilnamed;
use parent qw[ Log::Log4perl::Appender::File ];

      [download]

      Are you creating and entire module juste for the purpose of logging ? I mean, that's a good idea, I must admit it never accured to me that I could do so... And the use parent, what is it doing precisely please ?

      If I understand quite well, you are creating an object to create a new name at every launch of the main script ? And you are calling it at the intialization of the logger ? Does this allows me to have the exact same logfile name for my script and its module ? (I mean, even if there's a delay of about a second between the two initializatons)

      And thanks for the way you are naming your file, basically I use the same, but I'll stick to my method, it seems rather complicated the way you do it, at least to complicate for me...

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        And the use parent, what is it doing precisely please ?

        If you're really interested, read about it :) perldoc parent

        output 

        $ dir /b
shabba.pl

$ perl shabba.pl

$ dir /b
A1.2012-10-29T10-49-10Z.log
A2.2012-10-29T10-49-11Z.log
Logfile.2012-10-29T10-49-10Z.log
shabba.pl

$ cat A1.2012-10-29T10-49-10Z.log
2012/10/29 03:49:10 INFO> shabba.pl:43 main::Main - (Groceries) Import
+ant Info!
2012/10/29 03:49:10 INFO> shabba.pl:44 main::Main - (Groceries) Import
+ant Info! THEN NEWLINE
THEN IMPORTANTINFO

$ cat A2.2012-10-29T10-49-11Z.log
2012/10/29 03:49:10 INFO> shabba.pl:48 main::Main - (Junk) UnImportant
+ Info!

$ cat Logfile.2012-10-29T10-49-10Z.log
2012/10/29 03:49:10 shabba.pl 43> (Groceries) Important Info!
2012/10/29 03:49:10 shabba.pl 44> (Groceries) Important Info! THEN NEW
+LINE
THEN IMPORTANTINFO
2012/10/29 03:49:10 shabba.pl 48> (Junk) UnImportant Info!
2012/10/29 03:49:10 shabba.pl 83> (Bar.Twix) Twix mjam
2012/10/29 03:49:10 shabba.pl 83> (Bar.Twix) Twix mjam
2012/10/29 03:49:10 shabba.pl 83> (Bar.Twix) YAM NEWLINE
Twix mjam
2012/10/29 03:49:10 shabba.pl 83> (Bar.Twix) YAM NEWLINE
Twix mjam
2012/10/29 03:49:10 shabba.pl 87> (Bar.Mars) Mars mjam
2012/10/29 03:49:10 shabba.pl 87> (Bar.Mars) Mars mjam
2012/10/29 03:49:10 shabba.pl 87> (Bar.Mars) YAM NEWLINE
Mars mjam
2012/10/29 03:49:10 shabba.pl 87> (Bar.Mars) YAM NEWLINE
Mars mjam

        [download]

        testcase (creates 3 logfiles on each run)

        <Reveal this spoiler or all spoilers in this node or all in this thread>
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