gistfile1.PL

use 5.10.0;
use MooseX::Declare;
use Bread::Board;

class ParentConfig {
    has base_directory => ( is => 'ro', isa => 'Str', required => 1 );
    has media_directory => (
        isa        => 'Str',
        is         => 'ro',
        lazy_build => 1,
    );
    sub _build_media_directory { shift->base_directory . '/media' }
}

class HostConfig {
    has hostname       => ( is => 'ro', isa => 'Str', required => 1 );
    has base_directory => ( is => 'ro', isa => 'Str', required => 1 );
}

my $c = container ExampleConfig => as {
    service base_directory => '/var/tmp/myapp.config';

    service parent_config => (
        class        => 'ParentConfig',
        lifecycle    => 'Singleton',
        dependencies => [ depends_on('base_directory'), ],
    );

    service hostnames => (
        block => sub {
            return [
                qw(
                  foo.com
                  bar.com
                  baz.com
                  )
            ];
        }
    );

    service host_configs => (
        block => sub {
            my @hosts;
            for my $name ( @{ $_[0]->param('hostnames') } ) {
                push @hosts => HostConfig->new(
                    base_directory => $_[0]->param('parent_config'),
                    hostname       => $name
                );
            }
            return \@hosts;
        },
        dependencies =>
          [ depends_on('hostnames'), depends_on('parent_config'), ],
    );

    service app_config => (
        block {
            return {
                parent_config => $_[0]->param('parent_config'),
                host_configs  => $_[0]->param('host_configs'),
            };
        }
    );
};

my $config = $c->fetch('app_config')->get;