Ruby Scripting Part II

Ruby's Net::SSH is pretty cool. Here's a script to SSH into a set of hosts and do some work. It assumes that you're using sudo with local passwords and well as public keys.

#!/usr/bin/ruby
# -------------------------------------------------------- 
# SSH's into a set of hosts as user (assumes he has sudo)
# Uses local password (gathered earlier) to execute a set 
# of commands as root
# -------------------------------------------------------- 
require 'rubygems' 
require 'net/ssh'
# -------------------------------------------------------- 
# Store systems & commands to be run as whom
user = "user"
hosts = Array.new
hosts[0] = "system1"
hosts[1] = "system2"
cmds = Array.new
cmds[0] = "touch x"
cmds[1] = "touch y"
cmds[2] = "touch z"
# -------------------------------------------------------- 
# Cache tokens
print "Enter local password for hosts (assuming same): "
system("stty -echo") # hide input (password)
password = gets.chomp.to_s
system("stty echo") # show input again
print "\n"
# use ssh agent to cache key
system("ssh-agent")
system("ssh-add")
# -------------------------------------------------------- 
# SSH into each host and sudo execute commands
hosts.each do |host|
  Net::SSH.start(host, user) do |session|
    shell = session.shell.open
    shell.cd "/home/#{user}"
    cmds.each do |cmd|
      shell.echo "#{password} | sudo -S #{cmd}"
    end
    shell.exit
    # give the above commands sufficient time to terminate
    sleep 0.5
    # display the output
    $stdout.print shell.stdout while shell.stdout?
    $stderr.puts "-- stderr: --"
    $stderr.print shell.stderr while shell.stderr?
  end
end
# -------------------------------------------------------- 
# Clean out cached tokens
password = ""
system("ssh-add -d ~/.ssh/id_rsa")