Log::Log4perl::Config::BaseConfigurator(3) Configurator Base Class


This is a virtual base class, all configurators should be derived from it.



Constructor, typically called like

    my $config_parser = SomeConfigParser->new(
        file => $file,
    my $data = $config_parser->parse();

Instead of "file", the derived class "SomeConfigParser" may define any type of configuration input medium (e.g. "url => 'http://foobar'"). It just has to make sure its "parse()" method will later pull the input data from the medium specified.

The base class accepts a filename or a reference to an array of text lines:

Specifies a file which the "parse()" method later parses.
Specifies a reference to an array of scalars, representing configuration records (typically lines of a file). Also accepts a simple scalar, which it splits at its newlines and transforms it into an array:

    my $config_parser = MyYAMLParser->new(
        text => ['foo: bar',
                 'baz: bam',
    my $data = $config_parser->parse();

If either "file" or "text" parameters have been specified in the constructor call, a later call to the configurator's "text()" method will return a reference to an array of configuration text lines. This will typically be used by the "parse()" method to process the input.

Virtual method, needs to be defined by the derived class.

Parser requirements

  • If the parser provides variable substitution functionality, it has to implement it.
  • The parser's "parse()" method returns a reference to a hash of hashes (HoH). The top-most hash contains the top-level keywords ("category", "appender") as keys, associated with values which are references to more deeply nested hashes.
  • The "log4perl." prefix (e.g. as used in the PropertyConfigurator class) is stripped, it's not part in the HoH structure.
  • Each Log4perl config value is indicated by the "value" key, as in

        $data->{category}->{Bar}->{Twix}->{value} = "WARN, Logfile"


The following Log::Log4perl configuration:

    log4perl.category.Bar.Twix        = WARN, Screen
    log4perl.appender.Screen          = Log::Log4perl::Appender::File
    log4perl.appender.Screen.filename = test.log
    log4perl.appender.Screen.layout   = Log::Log4perl::Layout::SimpleLayout

needs to be transformed by the parser's "parse()" method into this data structure:

    { appender => {
        Screen  => {
          layout => { 
            value  => "Log::Log4perl::Layout::SimpleLayout" },
            value  => "Log::Log4perl::Appender::Screen",
      category => { 
        Bar => { 
          Twix => { 
            value => "WARN, Screen" } 
        } }

For a full-fledged example, check out the sample YAML parser implementation in "eg/yamlparser". It uses a simple YAML syntax to specify the Log4perl configuration to illustrate the concept.


Copyright 2002-2013 by Mike Schilli <[email protected]> and Kevin Goess <[email protected]>.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.


Please contribute patches to the project on Github:


Send bug reports or requests for enhancements to the authors via our

MAILING LIST (questions, bug reports, suggestions/patches): [email protected]

Authors (please contact them via the list above, not directly): Mike Schilli <[email protected]>, Kevin Goess <[email protected]>

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.