Identify a node's group by its short hostname

Fact originally identified the puppet client's Torque/PBS/etc. queue by short hostname. Can also be adapted to identify groups of HA servers or other pools of interchangeable nodes.

# hostgroup.rb
Facter.add("hostgroup") do
  # Limiting to Linux, since all my cluster systems are Linux-based.
  confine :kernel => :linux

  setcode do
    output = %x{hostname --short}.chomp
    #output = "ch409-1" ### Test case

    # Compact way of generating ch409-1 through ch409-14
    # from renke in #ruby

    ch409list = (1..14).map{|_| "ch409-#{_}"}

    # Map short hostname ranges to queues. Since I don't have a
    # fixed-format hostname structure for my cluster nodes, I need to
    # account for the double-digit ones first. Otherwise, hostname
    # "ch226-32" will fall into the range of
    # "ch226-3".."ch226-5".

    result = case output
             when "ch226-11".."ch226-19":
                 "pe1855-che"
             when "ch226-21".."ch226-32":
                 "sc1435"
             when "ch226-3".."ch226-5":
                 "pe2650"
             when "ch226-6".."ch226-7":
                 "pe1850"
             when "ch226-8":
                 "pe1850-cee"
             when "ch405a".."ch405n":
                 "ch405"
             when "ch406a".."ch406n":
                 "ch406"
             else "unknown"
             end

    if result=="unknown" and ch409list.include?(output):
        result = "ch409"
    end

    result
  end
end