map_stream.rb

# I have something like:
def map_stream source, destination, options_and_mapping
  option1 = options_and_mapping.delete :option1
  quiet = options_and_mapping.delete :quiet
  
  source.each do |input_record|
    output_record = map_record input_record, options_and_mapping
    some_extra_operation(output_record,option1) if option1
    @logger.info("mapped record #{input_record} to #{output_record}") unless quiet
    destination.insert output_record
  end
end

# and I use it like:
map_stream db1[query], db2[table1], 
  # options
  quiet: true, 
  # fields map
  xptr: :external_pointer, 
  nmbr: :item_number

spreadsheet = CSV.open(excel_import_file, headers: true, header_converters: :symbol)
map_stream spreadsheet, db2[table2], 
  # options
  option1: 42,
  # fields map
  pop: :population,
  mr: :mortality_rate