self.calculate_updated_order

in cookbooks/fb_storage/libraries/storage.rb [451:493]

• 36 lines of code
• 4 McCabe index (conditional complexity)

    def self.calculate_updated_order(prev, devs)
      Chef::Log.debug(
        'fb_storage: Attempting to merge old and new config',
      )
      new_mapping = prev.dup
      slots_to_replace = []

      Chef::Log.debug("fb_storage: previous list: #{prev}")
      Chef::Log.debug("fb_storage: current devs: #{devs}")

      prev.each_with_index do |disk, index|
        slots_to_replace << index unless devs.include?(disk)
      end

      new_disks = devs.reject do |disk|
        prev.include?(disk)
      end

      if new_disks.size != slots_to_replace.size
        fail 'fb_storage: Could not map disks to previous ' +
          "ordering: new disks: #{new_disks}, avail slots: " +
          "#{slots_to_replace}."
      end

      if new_disks.size.zero?
        fail 'fb_storage: Found no difference between old' +
          ' and new disks, but somehow didn\'t think they were the same' +
          ' before. Bailing out because I\'m very scared.'
      end
      new_disks.each_with_index do |disk, index|
        slot = slots_to_replace[index]
        new_mapping[slot] = disk
      end

      Chef::Log.info(
        "fb_storage: Previous disk mapping: #{prev}",
      )
      Chef::Log.info(
        "fb_storage: New disk mapping: #{new_mapping}",
      )
      new_mapping
    end