An example of using cPanel standardized hooks that executes when an addon domain is created.

YourAddonHook.pm

#!/usr/bin/env perl

package YourAddonModule;

use warnings;
use strict;

sub describe {
	my $create_addon_hook = 
		{
			'category' => 'Cpanel',
			'event' => 'Api2::AddonDomain::addaddondomain',
			'stage' => 'pre', # or post
			'hook' => 'YourAddonModule::your_hook_subroutine',
			'exectype' => 'module',
		};
	return [$create_addon_hook];
}

sub your_addon_hook {
	my ( $context, $data ) = @_;
	my $args = $data->{'args'};
	my ( $dir, $newdomain, $subdomain ) = ( $args->{'dir'}, $args->{'newdomain'}, $args->{'subdomain'} );
	print "HOOK TEST : Created $newdomain with dir = $dir and subdomain = $subdomain","\n";
}