MDC(3)

📦
version 1.57 · 9 versions
, in opensuse-leap 16.0

🌸 NAME 🌸

MDC(3) from the User Contributed Perl Documentation, bestie: this page is about Log::Log4perl::MDC - Mapped Diagnostic Context. That's the whole name, and yes, it's giving very "I hold your little log keys" energy. 💖

🦋 DESCRIPTION 🦋

Okay so Log::Log4perl lets loggers maintain global thread-specific data, and those two cuties are called the Nested Diagnostic Context (NDC) and Mapped Diagnostic Context (MDC). ✨

The MDC is a simple thread-specific hash table, no cap. Your application can stuff values under certain keys and retrieve them later through the %X{key} placeholder in Log::Log4perl::Layout::PatternLayouts. It's lowkey a tiny key-value stash for your logging era. 💅

🎀 The methods, bestie 🎀

  • Log::Log4perl::MDC->put($key, $value); — Store a value $value under key $key in the map. Obsessed with the directness. 💅
  • my $value = Log::Log4perl::MDC->get($key); — Retrieve the content of the map under the specified key. Typically done by %X{key} in Log::Log4perl::Layout::PatternLayout. If no value exists to the given key, undef is returned. 🙈
  • my $text = Log::Log4perl::MDC->remove(); — Delete all entries from the map. Clean slate, main character energy. ✨
  • Log::Log4perl::MDC->get_context(); — Returns a reference to the hash table. Very "here's the whole stash, bestie." 🫶
Important vibe check: all of the methods above are class methods, and there's no instances of this class. Since the thread model in perl 5.8.0 is "no shared data unless explicitly requested" the data structures used are just global (and therefore thread-specific). 🫶

💜 LICENSE 💜

Copyright 2002-2013 by Mike Schilli <m@perlmeister.com> and Kevin Goess <cpan@goess.org>.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. Slay, it's Perl-licensed. 🎀

🌈 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@lists.sourceforge.net

Authors (please contact them via the list above, not directly): Mike Schilli <m@perlmeister.com>, Kevin Goess <cpan@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.

✨ That's the whole page, bestie! Mwah. 💖 Source/version: perl v5.42.0; date: 2022-10-22; manual: MDC(3). 🎀

📦 where this page comes from