I seem unable to pull my listen_socket from the configuration. Can anyone please advise?

gistfile1.txt

#!/usr/bin/env perl

use strict;
use warnings;

use FindBin;
BEGIN {
    unshift @INC, '/opt/local/mojo/lib/perl5';
    unshift @INC, "$FindBin::Bin/../lib";
    unshift @INC, "$FindBin::Bin/../local";
}

# Start command line interface for application
require Mojolicious::Commands;
# Mojolicious::Commands->start_app('TFC', 'daemon', '-l', 'http://*:8007');

my $mode = $ENV{'MOJO_MODE'};
unless( defined( $mode ) ) {
  die "Got |$mode|, please 'export MOJO_MODE=<environment>` and try again";
}

my $app = Mojolicious::Commands->new->app;
my $listen_socket = $app->config->{'default'}->{'listen'} || 8007;
# $app->start( qw/TFC daemon -l/, "http://*:$listen_socket" );

Mojolicious::Commands->start_app('TFC', 'daemon', '-l', "http://*:$listen_socket" );

-----  

less conf.d/tfc_dev.conf --

[default]
environment=dev
listen=8009

------  

lib/TFC.pm -- 

sub startup {
  my $self = shift;

  $self->plugin('INIConfig', {file => 'conf.d/tfc_' . $self->mojo_mode . '.conf'});

}

sub mojo_mode {
  my $self = shift;
  return $ENV{'MOJO_MODE'};
}

-----  

was able to make this work:

#!/usr/bin/env perl

use strict;
use warnings;

use FindBin;
BEGIN {
    unshift @INC, '/opt/local/mojo/lib/perl5';
    unshift @INC, "$FindBin::Bin/../lib";
    unshift @INC, "$FindBin::Bin/../local";
}

my $mode = $ENV{'MOJO_MODE'};
unless( defined( $mode ) ) {
  die "Got |$mode|, please 'export MOJO_MODE=<environment>` and try again";
}

my %listen_socket = (
         'prod' => 80,
   'ci_sqlite3' => 8005,
        'ci_pg' => 8006,
          'uat' => 8007,
  'development' => 8008,
          'dev' => 8009,
);

# Start command line interface for application
require Mojolicious::Commands;
my $listen_socket = $listen_socket{ $mode };
Mojolicious::Commands->start_app('TFC', 'daemon', '-l', "http://*:$listen_socket" );

-----  

although it unfortunately replicates configuration in the script which 
more properly belongs in the config files, I think.  But this will get me going again.