Some magic here

modify.sh

#!/bin/bash
# docker exec -it 220v_apache_1 cpanm DBI::Log
# git diff to check changes

sed -i '15iuse main_config;' htdocs/cgi-bin/a0/pbh-preprocessor.pl
sed -i '16iuse DBI::Log file => "debug.log";' htdocs/cgi-bin/a0/pbh-preprocessor.pl
sed -i '21iuse Middleware::Stacktrace;' framework/lib/Perl5/DDV/ControllerRunner.pm

cat >framework/lib/Perl5/Middleware/Stacktrace.pm <<'EOL'
package Middleware::Stacktrace;
use strict;
use warnings FATAL => 'all';
use parent qw/Uber::Middleware/;
use main_config;

use Log::Any qw($log);
use Log::Any::Adapter;
use File::Spec;
use List::MoreUtils qw(uniq);
no warnings 'redefine';

use Text::Tmpl2;
use DTL::Fast;
use Uber::Controller;

$ModPerl::PBHRegistry::DEBUG = 0;
my $live          = 1;
my $timeout       = 1;
my $dhtml_print   = 1;
my $log_level     = 'notice';
my @pbh_templates = ();
my @dtl_templates = ();

Log::Any::Adapter->set( 'Fille', file => 'debug.log', log_level => 'notice' );

sub print_log {
    my $msg = shift;
    $log->$log_level($msg);
}

$SIG{USR1} = sub {
    @pbh_templates = uniq @pbh_templates;
    @dtl_templates = uniq @dtl_templates;
    if ( !$live ) {
        print_log("--- Rendered THTML templates --- ");
        print_log($_) for (@pbh_templates);
        print_log("--- Rendered DTL templates --- ");
        print_log($_) for (@dtl_templates);
    }
};

my $ppid = $$;
if ( fork() == 0 ) {
    sleep $timeout;
    kill 'USR1', $ppid;
    exit;
}

if ($main_config::DEBUG) {

    my $z = \&Text::Tmpl2::render;
    *Text::Tmpl2::render = sub {
        my $pbh_tpl_rel_path = File::Spec->abs2rel( $_[0]->{filename}, '/var/www/ccxx/' );
        push( @pbh_templates, $pbh_tpl_rel_path ) if !$live;
        print_log( "Rendering template " . $pbh_tpl_rel_path ) if $live;    # on render finish
        goto &$z;
    };

    my $gt = \&DTL::Fast::get_template;
    *DTL::Fast::get_template = sub {
        print_log( "Rendering template " . $_[0] ) if ( $live && $dhtml_print );
        push( @dtl_templates, $_[0] ) if !$live;
        goto &$gt;
    };

    my $pr = \&Uber::Controller::create_page_response;
    *Uber::Controller::create_page_response = sub {
        print_log( "Routing to controller " . ref( $_[0] ) );
        goto &$pr;
    };

}

sub process_request {
    my ( $self, $request ) = @_;
    return $request;
}

1;
EOL

tail -f htdocs/cgi-bin/a0/debug.log