ferreira.pl

use Mojo::Base -strict;
use feature 'current_sub';

use Mojo::IOLoop;

my $concurrency = 100;

# this is dummy data, fill it with your data to be processed
my @items = (1..1000);

sub do_batch {
  my $cb = shift;
  Mojo::IOLoop->delay(
    sub {
      my $delay = shift;
      for (1..$concurrency) {
        last unless @items;
        my $item = shift @items;
        my $end = $delay->begin;

        # this is a dummy, replace with your actual work
        Mojo::IOLoop->timer(1 => sub { say $item; $end->() });
      }
    },
    sub { $cb->() },
  );
}

# this callback basically reschedules itself (trampolines) until done
do_batch(sub{ @items ? do_batch(__SUB__) : say 'done' });

Mojo::IOLoop->start;