#!/usr/bin/perl

use strict;
use warnings;

use Net::OpenSSH::Parallel 0.12;
use Net::OpenSSH::Parallel::Constants qw(OSSH_ON_ERROR_IGNORE);

@ARGV == 3 or die <<EOU;
Usage:
  $0 host src_dir dst_dir

EOU

my ($host, $src, $dst) = @ARGV;

opendir my $dh, $src or die "unable to open $src";
my @ls = grep !/^\.{1,2}$/, readdir $dh;
close $dh;

my %now;
sub on_error {
    my ($pssh, $label, $error) = @_;
    warn "transfer of $now{$label} by $label failed\n";
    OSSH_ON_ERROR_IGNORE;
}

sub fetch_next {
    my ($pssh, $label) = @_;
    if (@ls) {
        my $file = shift @ls;
        $now{$label} = $file;
        warn "$label is copying $file\n";
        $pssh->push($label, rsync_put => "$src/$file", "$dst/$file");
        $pssh->push($label, sub => \&fetch_next);
    }
}

my $p = Net::OpenSSH::Parallel->new(on_error => \&on_error);

$p->add_host("worker$_", $host) for 1..5;
$p->all(sub => \&fetch_next);
$p->run;