gistfile1.txt

    def process_monthly_crates(crate_date=DateTime.now)
    
      # find the appropriate spree variant for this date / tshirt size.  There could be more than one.
      # let's create a hash of available variants and their available inventory
      variants = {}
    
      
      all_active_subscriptions = # find in batches
    
      all_active_subscriptions.each do |sub|
        begin
          period=sub.current_period
        end while !period.active? || period.nil?
      
        if period
          # we have an active period
    
          # grab from the variants hash above and update the available quantiy.  when it reaches 0, remove it from the hash and use the next key in the hash.  
          # in other words, if I have 100,000 of one sku, and 50,000 of another, run through 100,000 of one first
          variant = #
    
          sub_unit = period.subscription_units.create!(variant_id: variant.id)
          
          # create a json represenation of this sub_unit and push it to wombat 
          # this will make use of some method i have laying around that generates a specific order # (see OrderNumberGenerator in lib/spree for the way it should work)           
        else
          # this is an error condition - an active subscription w/ no active periods
          # TODO: handle this
        end  
      end
    end

I'd say this could/should be amended to accept the list of skus for "this month" (see comments ins https://lootcrate.atlassian.net/browse/LC-294)