Config::MVP::Reader - object to read config from storage into an assembler


version 2.200013


  use Config::MVP::Reader::YAML; # this doesn't really exist

  my $reader   = Config::MVP::Reader::YAML->new;

  my $sequence = $reader->read_config('/etc/foobar.yml');


A Config::MVP::Reader exists to read configuration data from storage (like a file) and convert that data into instructions to a Config::MVP::Assembler, which will in turn convert them into a Config::MVP::Sequence, the final product.


This module should work on any version of perl still receiving updates from the Perl 5 Porters. This means it should work on any version of perl released in the last two to three years. (That is, if the most recently released version is v5.40, then this module should work on both v5.40 and v5.38.)

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.



If true (which it is by default) then the current working directly will be locally added to @INC during config loading. This helps deal with changes made in Perl v5.26.1.



  my $sequence = $reader->read_config($location, \%arg);

This method is passed a location, which has no set meaning, but should be the mechanism by which the Reader is told how to locate configuration. It might be a file name, a hashref of parameters, a DBH, or anything else, depending on the needs of the specific Reader subclass.

It is also passed a hashref of arguments, of which there is only one valid argument:

 assembler - the Assembler object into which to read the config

If no assembler argument is passed, one will be constructed by calling the Reader's build_assembler method.

Subclasses should generally not override read_config, but should instead implement a read_into_assembler method, described below. If a subclass does override read_config it should take care to respect the add_cwd_to_lib attribute, above.


This method should not be called directly. It is called by read_config with the following parameters:

  my $sequence = $reader->read_into_assembler( $location, $assembler );

The method should read the configuration found at $location and use it to instruct the $assembler (a Config::MVP::Assembler) what configuration to perform.

The default implementation of this method will throw an exception complaining that it should have been implemented by a subclass.


If no Assembler is provided to read_config's assembler parameter, this method will be called on the Reader to construct one.

It must return a Config::MVP::Assembler object, and by default will return an entirely generic one.


Ricardo Signes <>


This software is copyright (c) 2022 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.