perl script to autoselect best server for apt

[Evan Martin <eeyem@u.washington.edu>]

http.us.debian.org has multiple ips. This (rather simple) perl script will
use netselect (apt-get install netselect) and nslookup to pick the "best"
(fastest, closest) server.

For me, this makes a difference: from some servers, I get 10k/sec, and
from samosa.debian.org (which this script picked for me), I get almost
200k/sec.

Or, is there a reason *not* to always use one server?  I can imagine that
this may affect the loads on each server.  It does keep overall network
traffic down, though, because netselect factors in hop count.

Comments?

Evan.

#!/usr/bin/perl -w
# Uses netselect to find "best" (fastest, closest) server.
#
# Evan Martin <eeyem@u.washington.edu>
# Nov-11-1999

$host = 'http.us.debian.org';

print "Looking up $host...\n";
$iplist = nslookup($host, 'Addresses');
print "Available hosts: " . $iplist . "\n";
print "netselect'ng best host...\n";

open(NETSEL, "netselect " . join(' ', split(/\s*,\s*/, $iplist)) . "|") || die "netselect error";
$ip = (split(' ', <NETSEL>))[1];
close(NETSEL);

$besthost = nslookup($ip, 'Name');
print "Best host: $besthost\n";

sub nslookup() {
    my ($host, $word) = @_;
    open(NSLOOKUP, "nslookup $host 2>&1 |") || die "nslookup error";
    while (<NSLOOKUP>) {
        last if /$word/;
        if (/\*\*\*/) {
            print "nslookup says: $_";
            die "*** nslookup error";
        }
    }
    close(NSLOOKUP);
    s/$word:\s*//;
    chomp;
    return $_;
}