config_data - Man Page

  # Get config/feature values
  config_data --module Foo::Bar --feature bazzable
  config_data --module Foo::Bar --config magic_number

  # Set config/feature values
  config_data --module Foo::Bar --set_feature bazzable=1
  config_data --module Foo::Bar --set_config magic_number=42

  # Print a usage message
  config_data --help

The config_data tool provides a command-line interface to the configuration of Perl modules.  By "configuration", we mean something akin to "user preferences" or "local settings".  This is a formalization and abstraction of the systems that people like Andreas Koenig (CPAN::Config), Jon Swartz (HTML::Mason::Config), Andy Wardley (Template::Config), and Larry Wall (perl's own Config.pm) have developed independently.

The configuration system employed here was developed in the context of Module::Build.  Under this system, configuration information for a module Foo, for example, is stored in a module called Foo::ConfigData) (I would have called it Foo::Config, but that was taken by all those other systems mentioned in the previous paragraph...).  These ...::ConfigData modules contain the configuration data, as well as publicly accessible methods for querying and setting (yes, actually re-writing) the configuration data.  The config_data script (whose docs you are currently reading) is merely a front-end for those methods.  If you wish, you may create alternate front-ends.

The two types of data that may be stored are called config values and feature values.  A config value may be any perl scalar, including references to complex data structures.  It must, however, be serializable using Data::Dumper.  A feature is a boolean (1 or 0) value.

This script functions as a basic getter/setter wrapper around the configuration of a single module.  On the command line, specify which module's configuration you're interested in, and pass options to get or set config or feature values.  The following options are supported:

module

Specifies the name of the module to configure (required).

feature

When passed the name of a feature, shows its value.  The value will be 1 if the feature is enabled, 0 if the feature is not enabled, or empty if the feature is unknown.  When no feature name is supplied, the names and values of all known features will be shown.

config

When passed the name of a config entry, shows its value.  The value will be displayed using Data::Dumper (or similar) as perl code. When no config name is supplied, the names and values of all known config entries will be shown.

set_feature

Sets the given feature to the given boolean value.  Specify the value as either 1 or 0.

set_config

Sets the given config entry to the given value.

eval

If the --eval option is used, the values in set_config will be evaluated as perl code before being stored.  This allows moderately complicated data structures to be stored.  For really complicated structures, you probably shouldn't use this command-line interface, just use the Perl API instead.

help

Prints a help message, including a few examples, and exits.

Ken Williams, kwilliams@cpan.org

Copyright (c) 1999, Ken Williams.  All rights reserved.

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

Module::Build(3), perl(1).