Well, for fun I poked at Net::DBus, this will give you a service:

use 5.020;
use strict;
use warnings;

package My::Dog::Rex;
use Net::DBus::Exporter qw(org.my.rex.Runner);
use base qw(Net::DBus::Object);
# use Rex -feature => [qw/1.4/];

dbus_method("walk_dog", [], []);
sub walk_dog {
    my $self = shift;

    say "Walking the dog";
#     user "root";
#     password "ch4ngem3";
#
#     desc "Show system information";
#     task "sysinfo", sub {
#         say run "uname -a";
#     };
}

1;

package My::Rex::Service;
use base qw(Net::DBus::Service);

sub new {
    my $class = shift;
    my $self = $class->SUPER::new(@_);
    My::Dog::Rex->new($self, "/my/dog/rex");
    return $self;
}

package main;
use Net::DBus;
use Net::DBus::Reactor;

my $bus = Net::DBus->session;
my $rex = My::Rex::Service->new($bus, "org.my.rex");
Net::DBus::Reactor->main->run;

exit 0;
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This is how you would trigger methods (from a separate script)

use 5.020;
use strict;
use warnings;

use Net::DBus;

my $bus = Net::DBus->session;
my $rex = $bus->get_service("org.my.rex")->get_object("/my/dog/rex");
$rex->walk_dog;
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And when you want to run on the system bus instead of the user's session bus, change all the ->session to ->system, add the following to "/etc/dbus-1/system.d/org.my.rex.conf" and then run "systemctl reload dbus.service"

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuratio
+n 1.0//EN" "http://www.freedesktop.org/standards/dbus/1.0/busconfig.d
+td">
<busconfig>
   <!-- Root can own or use the Rex service -->
   <policy user="root">
      <allow own="org.my.rex"/>
      <allow send_destination="org.my.rex"/>
      <allow receive_sender="org.my.rex"/>
   </policy>

   <!-- Nobody else can do anything -->
   <policy context="default">
      <deny send_destination="org.my.rex"/>
      <deny receive_sender="org.my.rex"/>
   </policy>
</busconfig>
[download]