Provided by: libconfig-onion-perl_1.007-1_all bug

NAME

       Config::Onion - Layered configuration, because configs are like ogres

VERSION

       version 1.007

SYNOPSIS

         my $cfg = Config::Onion->new;
         my $cfg = Config::Onion->set_default(db => {name => 'foo', password => 'bar'});
         my $cfg = Config::Onion->load('/etc/myapp', './myapp');
         my $cfg = Config::Onion->load('/etc/myapp', './myapp', {use_ext => 1, filter => \&filter});
         my $cfg = Config::Onion->load_glob('./plugins/*');
         my $cfg = Config::Onion->load_glob('./plugins/*', {force_plugins => ['Config::Any::YAML']});

         $cfg->set_default(font => 'Comic Sans');
         $cfg->load('config');
         $cfg->load_glob('conf.d/myapp*');
         $cfg->set_override(font => 'Arial');

         my $dbname = $cfg->get->{db}{name};
         my $plain_hashref_conf = $cfg->get;
         my $dbpassword = $plain_hashref_conf->{db}{password};

DESCRIPTION

       All too often, configuration is not a universal or one-time thing, yet most configuration-
       handling treats it as such.  Perhaps you can only load one config file.  If you can load
       more than one, you often have to load all of them at the same time or each is stored
       completely independently, preventing one from being able to override another.
       Config::Onion changes that.

       Config::Onion stores all configuration settings in four layers: Defaults, Main, Local, and
       Override.  Each layer can be added to as many times as you like.  Within each layer,
       settings which are given multiple times will take the last specified value, while those
       which are not repeated will remain untouched.

         $cfg->set_default(name => 'Arthur Dent', location => 'Earth');
         $cfg->set_default(location => 'Magrathea');
         # In the Default layer, 'name' is still 'Arthur Dent', but 'location' has
         # been changed to 'Magrathea'.

       Regardless of the order in which they are set, values in Main will always override values
       in the Default layer, the Local layer always overrides both Default and Main, and the
       Override layer overrides all the others.

       The design intent for each layer is:

       •   Default

           Hardcoded default values to be used when no further configuration is present

       •   Main

           Values loaded from standard configuration files shipped with the application

       •   Local

           Values loaded from local configuration files which are kept separate to prevent them
           from being overwritten by application upgrades, etc.

       •   Override

           Settings provided at run-time which take precendence over all configuration files,
           such as settings provided via command line switches

       If a higher-priority layer wishes to completely remove a hash entry made by a lower-
       priority layer (i.e., delete the hash key, not just set it to an empty value), it can do
       so by setting the value to "!DELETE!".  This only applies to hash entries, not array
       values, as the entire array already needs to be overwritten to make any changes to it.
       Also, if, for some reason, the configuration contains objects, the contents of those
       objects will be ignored for the sake of encapsulation.  Only unblessed hashes are cleaned
       in this manner.

METHODS

   new
       Returns a new, empty configuration object.

   load(@file_stems) =head2 load(@file\_stems, {...})
       Loads files matching the given stems using "Config::Any->load_stems" into the Main layer.
       Also concatenates ".local" to each stem and loads matching files into the Local layer.
       e.g., "$cfg->load('myapp')" would load "myapp.yml" into Main and "myapp.local.js" into
       Local.  All filename extensions supported by "Config::Any" are recognized along with their
       corresponding formats.

       An optional hash ref final argument can be provided to override the default option
       "use_ext => 1" passed to "Config::Any".  All options supported by "Config::Any" are
       supported except flatten_to_hash.  See "Config::Any->load_files" documentation for
       available options.

   load_glob(@globs) =head2 load_glob(@globs, {...})
       Uses the Perl "glob" function to expand each parameter into a list of filenames and loads
       each file using "Config::Any".  Files whose names contain the string ".local." are loaded
       into the Local layer.  All other files are loaded into the Main layer.

       An optional hash ref final argument can be provided to override the default option
       "use_ext => 1" passed to "Config::Any".  All options supported by "Config::Any" are
       supported except flatten_to_hash.  See "Config::Any->load_files" documentation for
       available options.

   set_default([\%settings,...,] %settings)
   set_override([\%settings,...,] %settings)
       Imports %settings into the Default or Override layer.  Accepts settings both as a plain
       hash and as hash references, but, if the two are mixed, all hash references must appear at
       the beginning of the parameter list, before any non-hashref settings.

PROPERTIES

   cfg
   get
       Returns the complete configuration as a hash reference.

   default
   main
   local
   override
       These properties each return a single layer of the configuration.  This is not likely to
       be useful other than for debugging.  For most other purposes, you probably want to use
       "get" instead.

   prefix_key
       If set, enables the Prefix Structures functionality described below when using the "load"
       or "load_glob" methods.  The value of "prefix_key" specifies the name of the key under
       which the  prefix structure may be found.

       Default value is "undef".

Prefix Structures

       If you find that your configuration structure is becoming unwieldy due to deeply-nested
       structures, you can define a file-specific "prefix structure" and all other settings
       within that file will be loaded as children of the prefix structure.  For example, if your
       main program uses

         $cfg = Config::Onion->new(prefix_key => '_prefix');
         $cfg->load("myapp/config");

       and "myapp/config.yml" contains

         _prefix:
           foo:
             bar:

         baz: 1

       then $cfg will contain the configuration

         foo:
           bar:
             baz: 1

       Note that the top-level "prefix_key" is removed.

       There are some limitations on the prefix structure, in order to keep it sane and
       deterministic.  First, the prefix structure may only contain hashes.  Second, each hash
       must contain exactly one key.  Finally, the value associated with the final key must be
       left undefined.

BUGS AND LIMITATIONS

       No bugs have been reported.

       Please report any bugs or feature requests at
       <https://github.com/dsheroh/Config-Onion/issues>

AUTHOR

       Dave Sherohman <dsheroh@cpan.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2012 by Lund University Library.

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