Filter::MDC(3) User Contributed Perl Documentation Filter::MDC(3)

# [NAME](#NAME)

Log::Log4perl::Filter::MDC - Filter to match on values of a MDC key

# [SYNOPSIS](#SYNOPSIS)

```
    log4perl.filter.Match1               = Log::Log4perl::Filter::MDC
    log4perl.filter.Match1.KeyToMatch    = foo
    log4perl.filter.Match1.RegexToMatch  = bar
```

# [DESCRIPTION](#DESCRIPTION)

This Log4perl filter checks if a predefined MDC key, as set in "KeyToMatch", of the currently submitted message matches a predefined regex, as set in "RegexToMatch".

# [SEE ALSO](#SEE_ALSO)

Log::Log4perl::Filter, Log::Log4perl::Filter::Boolean, Log::Log4perl::Filter::LevelMatch, Log::Log4perl::Filter::LevelRange, Log::Log4perl::Filter::MDC, Log::Log4perl::Filter::StringMatch

# [LICENSE](#LICENSE)

Copyright 2002-2026 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.

2026-08-17 perl v5.44.0

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Document: Log::Log4perl::Filter::MDC(3pm) from perl-log-log4perl 1.58-r1 (Chainguard OS)
Source: https://github.com/mschilli/log4perl.git