Config::Role - Moose config attribute loaded from file in home dir


version 0.1.1


    package My::Class;
    use Moose;
    with 'Config::Role';

    # Read configuration from ~/.my_class.ini, available in $self->config
    # This is optional if you like this particular naming of the file
    has 'config_filename' => ( is => 'ro', isa => 'Str', lazy_build => 1 );
    sub _build_config_filename { '.my_class.ini' }

    # Fetch a value from the configuration, allow constructor override
    has 'username' => ( is => 'ro', isa => 'Str', lazy_build => 1 );
    sub _build_username { return (shift)->config->{'username'}; }

    sub make_request {
        my ($self) = @_;
        my $response = My::Class::Request->make(
            username => $self->username,


This is the problem Config::Role was created to solve: Give me a config attribute (hashref) which is read from a file in my home directory to give other attributes default values, with configurability to choose the file's location and name.


Config::Role is a very basic role you can add to your Moose class that allows it to take configuration data from a file located in your home directory instead of always requiring parameters to be specified in the constructor.

The synopsis shows how you can read the value of username from the file .my_class.ini located in the home directory of the current user. The location of the file is determined by whatever File::HomeDir->my_data returns for your particular platform.

The config file is loaded by using Config::Any's load_files() method. It will load the files specified in the config_files attribute. By default this is an array reference that contains the filename from the config_file attribute. If you specify multiple files which both contain the same configuration key, the value is loaded from the first file. That is, the most significant file should be first in the array.

The Config::Any->load_files() flag use_ext is set to a true value, so you can use any configuration file format supported by Config::Any by just specifying the common filename extension for the format.



The directory where the configuration file is located. A Path::Class::Dir object. Defaults to File::HomeDir->my_data. Allows coercion from Str.


The filename the configuration is read from. A Path::Class::File object. Allows coercion from Str. Default is calculated based on the composing class name. If your composing class is called My::Class it will be .my_class.ini. Remember that if you sub-class the composing class, the default will be the name of the sub-class, not the super-class.


The collection of filenames the configuration is read from. Array reference of Path::Class::File objects. Allows coercion from an array reference of strings.


A hash reference that holds the compiled configuration read from the specified files.



Optional attribute or method on the composing class. Should return a string with the name of the configuration file name. See config_file for how the default is calculated if this method is not available.

COMPARISON TO MooseX::ConfigFromFile

Config::Role doesn't require you to use anything else than $class->new() to actually get the benefit of automatic config loading. Someone might see this as negative, as it gives a minor performance penalty even if the config file is not present.

Config::Role uses File::HomeDir to default to a known location, so you only need to specify the file name you use, not a full path. This should give better cross-platform compatibility, together with the use of Path::Class for all file system manipulation.

Also, with Config::Role you must explicitly specify in the builder of an attribute that you want to use values from the config file. MooseX::ConfigFromFile seems to do that for you. You also get the benefit that the configuration file keys and the class attribute names does not need to map 1-to-1 (someone will probably see that as a bad thing).

Otherwise they are pretty similar in terms of what they do.


  • A nicely named sugar function could be exported to allow less boilerplate in generating attributes that default to config values.


This module uses semantic versioning concepts from




You can find documentation for this module with the perldoc command.

  perldoc Config::Role


The following websites have more information about this module, and may be of help to you. As always, in addition to those websites please use your favorite search engine to discover more resources.

Bugs / Feature Requests

Please report any bugs or feature requests by email to bug-config-role at, or through the web interface at You will be automatically notified of any progress on the request by the system.

Source Code

The code is open to the world, and available for you to hack on. Please feel free to browse it and play with it, or whatever. If you want to contribute patches, please send me a diff or prod me to pull from your repository :)

  git clone git://


Robin Smidsrød <>


This software is copyright (c) 2012 by Robin Smidsrød.

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