#!/usr/local/bin/ruby -w

require 'open3'
require 'timeout'
require 'thread'

mutex = Mutex.new

# You should redefine POOL for your own environment.
#POOL = /^134\.153\.51\.[56]\d\b/
POOL = /^134\.153\.51\.\d+\b/
SSH = '/usr/bin/ssh -x'
UPT = '/usr/bin/uptime'

threads = []
uptimes = []

File.new('/etc/hosts').readlines.delete_if { |l| l !~ POOL }.each { |l|
	ip, name = l.split.values_at(0, 2)

	threads << Thread.new(ip, name) { |tip, tname|
		output = ""
		begin
			timeout(30) {
				i, o, e = Open3.popen3("#{SSH} #{tip} #{UPT}")
				output = o.read
				output = e.read if output == ""
				#output.gsub!(/\s+/, " ")
				#output.gsub!(/^.* up /, "up ")
			}
		rescue TimeoutError => err
			output = "timeout exceeded"
		end
		mutex.synchronize { 
			uptimes << "%-12s %s" % [tname, output]
		}
	}
}
puts "Finished loop.  Waiting for threads..."

threads.each { |t| t.join }
puts uptimes.sort