Mojo::Log singleton in a Util package

Util.pm

# $ MOJO_LOG_LEVEL=info perl -Ilib -Mojo -MUtil=sq -E 'BEGIN { $Util::log = app->log; } a("/:n" => sub { $_->render(text => sq) })->start' get /5
# 36
# $ MOJO_LOG_LEVEL=trace perl -Ilib -Mojo -MUtil=sq -E 'BEGIN { $Util::log = app->log; } a("/:n" => sub { $_->render(text => sq) })->start' get /5
# [2026-06-08 17:10:33.96373] [87592] [trace] 6^2 = 36
# 36

package Util;
use Mojo::Base -strict, -signatures;

use Exporter qw(import);
use Mojo::Log;

our @EXPORT_OK = qw(sq);

our $log = Mojo::Log->new;

sub sq ($n=6) {
  my $n2 = $n * $n;
  $log->trace(sprintf '%d^2 = %d', $n, $n2);
  return $n2;
}

1;