A quick script to automatically choose the UTCS 32-bit server with the lowest current load

utcs.rb

#! /usr/bin/env ruby

# This script is pretty fragile in that it will break if the UTCS
# lab status page changes its HTML in a fairly small way. So far,
# it works great.

# It requires nokogiri (gem install nokogiri).

# I have my user name set automatically with my ssh-config file, so
# it doesn't figure into the ssh command below. Later, I might either 
# add some code for a -X flag with ssh, or maybe just switch to that 
# overall.

require 'rubygems'
require 'nokogiri'
require 'open-uri'

doc = Nokogiri::HTML(open('http://apps.cs.utexas.edu/unixlabstatus/'))

lines = doc.css('td.ruptime')

machines = Array.new

i = 6

while i+4 <= lines.length
  if lines[i].content == "Public Linux Workstations - 64-bit"
    i = i + 6000
  end
  if lines[i+1].content == "up"
    this_machine_name = lines[i].content
    this_machine_load = lines[i+4].content
    this_machine_data = Array[this_machine_name, this_machine_load]
    machines << this_machine_data
  end
  i = i+5
end

machines = machines.sort_by { |e| e[1] }

puts machines[0][0] + " has a load of " + machines[0][1]

exec "ssh " + machines[0][0] + ".cs.utexas.edu"