package MyApp; # modern Moo-based app
use Moo;

# run initialisation checks
# set up session, parse http params

# run routing code: load (legacy) module, run the code
load 'ConsumingModule';  # this module uses Utility.pm
ConsumingModule::run();

# render output

##</code><code>##

package Utility;
...
my ($cgi, $session, $dbh, $config, ...); # create (but don't set)
                                         # important variables
# do miscellaneous stuff
...
init();
...
sub init {
   $cgi = CGI->new();
   $session = CGI::Session->new( $params );
   ...
}

# later on
sub get_session_param {
   my $p = shift;
   return $session->param( $p );
}

sub set_session_param {
	my ($p, $val) = @_;
	$session->param( $p, $val );
}
# plus other stuff for interacting with $session

sub param {
    my $p = shift;
    return $cgi->param( $p );
}
# plus other cgi interactions

# 9950 lines of other code
# (including similar code for setting up database handles, http clients, and
# other functionality that I have roles for)

##</code><code>##

package ConsumingModule;
...
use Utility;

sub run {
	...
	my $query = param('query'); # get a CGI parameter
	...
	set_session_param('foo', 'bar'); # interact with the session
}