Gotta love the Moose!

xsawyerx on 2009-03-18T09:30:27

I wrote a Moose role that fetches and analyzes ifconfig output to nice hash of interfaces and IPs for each interface. I wanted to use Net::Ifconfig::Wrapper which seems highly portable but something didn't work properly with the virtual interfaces of VPS servers. Also, I ended up not being able to run remotely-installed modules. I tried IPC::PerlSSH which is nice but ended up opting for just fetching and parsing it. Sometimes it comes out faster, ya know?

I wanted to make sure I have the correct input and that means some additional testing in the code itself. It's loops and checks and more regexp and so on and so on. Instead, I decided to let Moose do the work:

use Moose::Role;
use Moose::Util::TypeConstraints;
use Data::Validate::IP qw( is_ipv4 );

requires qw( connect_server );

subtype 'Ifaces'
    => as 'HashRef',
    => where {
        foreach my $suspect_ip ( values %{ $_[0] } ) {
            is_ipv4($suspect_ip) || return 0;
        }
        return 1;
    }
    => message { 'Incorrect Ifaces' };

has 'ifaces' => (
    is  => 'rw',
    isa => 'Ifaces',
);

Then, in my testing suite I wrote this additional test:

use Test::More  qw( no_plan );
use Test::Block qw( $Plan   );
use Test::Exception;

# ... some more stuff up here ...

{ # testing ifaces type
    local $Plan = 2;
    my %ifaces = (
        'venet0' => '1.1.2.3',
        'venet2' => '1.2.3.4',
        'venet3' => '2.2.2.2',
    );

    ok( $map->ifaces(\%ifaces), 'good ifaces' );

    $ifaces{'venet0'} = '1.2.3.';

    throws_ok { $map->ifaces(\%ifaces) } qr/Incorrect Ifaces/,
        'bad ifaces';
}

Sidenote: isn't it weird that the cookbook for Moose says "How to cook a Moose?" Love the Moose, don't cook it! (have it help you in the kitchen, maybe?)

... and people should stop telling me there's more than one way to skin a cat. Quit skinning cats, people, it's very unnerving :)