NAME

       MooseX::Attribute::ENV - Set default of an attribute to a value from %ENV

SYNOPSIS

       The following is example usage for this attribute trait.

               package MyApp::MyClass;

               use Moose;
               use MooseX::Attribute::ENV;

               ## Checks $ENV{username} and $ENV{USERNAME}
               has 'username' => (
                       traits => ['ENV'],
               );

               ## Checks $ENV{GLOBAL_PASSWORD}
               has 'password' => (
                       traits => ['ENV'],
                       env_key => 'GLOBAL_PASSWORD',
               );

               ## Checks $ENV{last_login}, $ENV{LAST_LOGIN} and then uses the default
               has 'last_login' => (
                       traits => ['ENV'],
                       default => sub {localtime},
               );

               ## Checks $ENV{XXX_config_name} and $ENV{XXX_CONFIG_NAME}
               has 'config_name' => (
                       traits => ['ENV'],
                       env_prefix => 'XXX',
               );

               ## Checks $ENV{MyApp_MyClass_extra} and $ENV{MYAPP_MYCLASS_EXTRA}
               has 'extra' => (
                       traits => ['ENV'],
                       env_package_prefix => 1,
               );

       Please see the test cases for more detailed examples.

DESCRIPTION

       This is a Moose attribute trait that you use when you want the default value for an
       attribute to be populated from the %ENV hash.  So, for example if you have set the
       environment variable USERNAME = 'John' you can do:

               package MyApp::MyClass;

               use Moose;
               use MooseX::Attribute::ENV;

               has 'username' => (is=>'ro', traits=>['ENV']);

               package main;

               my $myclass = MyApp::MyClass->new();

               print $myclass->username; # STDOUT => 'John';

       This is basically similar functionality to something like:

               has 'attr' => (
                       is=>'ro',
                       default=> sub {
                               $ENV{uc 'attr'};
                       },
               );

       but this module has a few other features that offer merit, as well as being a simple
       enough attribute trait that I hope it can serve as a learning tool.

       If the named key isn't found in %ENV, then defaults will execute as normal.

ATTRIBUTES

       This role defines the following attributes.

   env_key ($Str)
       By default we look for a key in %ENV based on the actual attribute name.  If want or need
       to override this behavior, you can use this modifier.

   env_prefix ($Str)
       A prefix to attach to the generated filename.  The prefix is prepended with a trailing
       underscore. For example, if you attribute was 'attr' and your set a prefix of 'xxx' then
       we'd check for $ENV{xxx_attr} and $ENV{XXX_ATTR}.

   env_package_prefix ($Bool)
       Similar to env_prefix, but automatically sets the prefix based on the consuming classes
       package name.  So if your attribute is 'attr' and it's in a package called:
       'Myapp::Myclass' the follow keys in %ENV will be examined:

       * Myapp_Myclass_attr * MYAPP_MYCLASS_ATTR

       Please be aware that if you use this feature, your attribute will automatically be
       converted to lazy, which might effect any default subrefs you also assign to this
       attribute.

       Please note that you can't currently use this option along with the option 'lazy_build'.
       That might change in a future release, however since these attributes are likely to hold
       simple strings the lazy_build option probably won't be missed.

METHODS

       This module defines the following methods.

   _process_options
       Overload method so that we can assign the default to be what's in %ENV

AUTHOR

       John Napiorkowski, "<jjnapiork at cpan.org>"

BUGS

       Please report any bugs or feature requests to:

               C<MooseX-Attribute-ENV at rt.cpan.org>

       or through the web interface at:

               L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=MooseX-Attribute-ENV>

       I will be notified, and then you'll automatically be notified of progress on your bug as I
       make changes.

SUPPORT

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

           perldoc MooseX::Attribute::ENV

       You can also look for information at:

       •   RT: CPAN's request tracker

           <http://rt.cpan.org/NoAuth/Bugs.html?Dist=MooseX-Attribute-ENV>

       •   AnnoCPAN: Annotated CPAN documentation

           <http://annocpan.org/dist/MooseX-Attribute-ENV>

       •   CPAN Ratings

           <http://cpanratings.perl.org/d/MooseX-Attribute-ENV>

       •   Search CPAN

           <http://search.cpan.org/dist/DBIx-Class-PopulateMore>

LICENSE

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