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CONFIG_DATA

Section: User Contributed Perl Documentation (1)
Updated: 2016-07-08
Index Return to Main Contents

NAME

config_data - Query or change configuration of Perl modules

SYNOPSIS

  # 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

DESCRIPTION

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.

USAGE

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.