#!/usr/bin/perl

use strict;
use warnings;
use DBI;

my $db_user = 'DBUSER';
my $db_pass = 'DBPASS';

my $dbh = DBI->connect('DBI:mysql:cacti', $db_user, $db_pass)
    or die "Couldn't connect to database: " . DBI->errstr;

while(<>) {
    my $ip = $_;
    chomp $ip;
    next if $ip eq "";
    my $host_id = getHostID($ip);
    printf("%d\n", $host_id);
}

sub getHostID {
    my $ip = shift;
    my $sth = $dbh->prepare('SELECT id FROM host WHERE hostname = ?')
        or die "Couldn't prepare statement: " . $dbh->errstr;
    $sth->execute($ip);
    my $id = $sth->fetchrow();
    return $id;
}