gluster volfile parser / extractor

gluster2yaml.rb

#!/usr/bin/env ruby

require 'yaml'

class GlusterConfError < Exception
end

def assert x, *bool
  bool.each { |b| raise GlusterConfError, "#{$.}: #{x}" unless bool }
end

volh = {}
vol = {}

$<.each { |l|
  ls = l.split
  case ls[0]
  when "volume"
    assert l, ls.size == 2, vol.empty?
    vol["name"] = ls[1]
  when "type"
    assert l, ls.size == 2, vol["name"], !vol["type"]
    vol["type"] = ls[1]
  when "option"
    assert l, ls.size == 3, vol["name"]
    (vol["option"] ||= {})[ls[1]] = case ls[2]
    when /\A\d+\Z/
      Integer ls[2]
    when /\Aon|yes|true|enable\Z/i
      true
    when /\Aoff|no|false|disable\Z/i
      false
    else
      ls[2]
    end
  when "subvolumes"
    assert l, ls.size > 1, vol["name"], !vol["subvolumes"]
    vol["subvolumes"] = ls[1..-1]
  when "end-volume"
    assert l, ls.size == 1, vol["name"], vol["type"]
    volh[vol["name"]] = vol 
    vol = {}
  when nil
  else
    assert l, false
  end
}

subvolumes = [] 
volh.each_value { |vol| subvolumes.concat(vol["subvolumes"] || []) }
topvols = volh.keys - subvolumes
assert "ambiguous toplevel volume: #{topvols.join(", ")}", topvols.size == 1
topvol = volh[topvols[0]]

volh.each_value { |vol| (vol["subvolumes"] || []).map! { |w| volh[w] } }

puts topvol.to_yaml