anyevent non-blocking port check template

gistfile1.txt

#!/usr/bin/env perl

use strict;
use warnings;
use AnyEvent::Socket;

use constant INTERVAL => 1;

my ($host, $port) = @ARGV;

die "No host name is given" unless defined $host;
die "No port numb is given" unless defined $port;

my $cv = AnyEvent->condvar;

my $once_per_second;
   $once_per_second = AnyEvent->timer(interval => INTERVAL,
				      cb       => \&port_check,
);

$cv->recv;

sub port_check {
  tcp_connect $host, $port, sub {
    my ($fh) = @_ or do {
      die "The host or service is down\n"; # print 'timeout' at most every second
    };

    warn "Host is alive";
  };
}