{
	package User;
	use Moose;
	
	has name => (is => 'ro', isa => 'Str');
	
	sub login {
		my $self = shift;
		print $self->name, " is logged in\n";
	}
}

{
	package Tracing;
	use MooseX::Aspect;
	
	my $aspect = __PACKAGE__;
	
	sub log_msg {
		my $class = shift;
		print STDERR "TRACE: $_\n" for @_;
	}
	
	apply_to 'User' => role {
		before login => sub {
			my $self = shift;
			$aspect->log_msg($self->name . " attempted to log in");
		};
	};
}

# try setting tracing to 0 :-)
my $config = { tracing => 1 };

if ($config->{tracing}) {
	Tracing->setup;
}

my $bob = User->new( name => 'Bob' );
$bob->login;