Puppet fact to handle Xen device offsets

xen_blk_facter.rb

require 'facter'

def get_xen_ephemeral_device(index)
  dev = Facter.value("ec2_block_device_mapping_ephemeral#{index}")
  if !dev.nil?
    xendev = "xvd",(dev[2] + 4).chr
    if dev.length > 3
      xendev = format("%s%s", xendev, dev[3, dev.length])
    end
    return xendev
  else
    xendev = nil
  end
end

if system 'lsmod | grep xen_blkfront >> /dev/null'
  `uname -r` =~ /(\d)\.(\d)\.(\d+)/
  if Integer($1) == 2 and Integer($2) == 6 and Integer($3) >= 32
    (0..8).each { |i|
      Facter.add("ec2_xen_block_device_mapping_ephemeral#{i}") do
        setcode do
          dev = get_xen_ephemeral_device(i)
        end
      end
    }
  end
end