Convert a dynamodb result [json] to csv

dynamo_json_to_csv.py

#!/usr/bin/python3
# -*- coding: UTF-8 -*-

__author__ = "Elio Capelati Jr"
__version__ = "1.0.0"  


import csv, json, sys, argparse
from pprint import pprint


def main(**kwargs):
	values = transform_values(parse_json(kwargs['file_input']))
	write_csv(values, kwargs['save'], kwargs['header'])


def transform_values(items):
	"""
		Transform a Item[n]:
			{
	            "id": {
	                "N": "123"
	            }, 
	            "ttl": {
	                "N": "594777600"
	            }, 
	            ...
           }
        Into: 
        	{"id": "123", "ttl" :"594777600"}
	"""
	returnvalues = []
	for item in items:
		keys = item.keys()
		itemloop = {}
		for value in keys:
			k, v = item.get(value).popitem()
			itemloop[value] = v
		returnvalues.append(itemloop)
	return returnvalues


def parse_json(file_path):
	data = json.load(args.input)
	return data.get('Items', None)


def write_csv(values, save, header):
	"""
		Write a dict to CSV format including the header
	"""
	output = csv.writer(save)
	if header:
		output.writerow(values[0].keys())
	
	for row in values:
		output.writerow(row.values())

if __name__ == '__main__':
	parser = argparse.ArgumentParser(description='Parse DynamoDb table Items to a CSV')
	
	parser.add_argument('input', nargs='?', type=argparse.FileType('r'),
						 default=sys.stdin, 
						 help="""Input a Dynamodb JSON file ref: 
						 http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Programming.LowLevelAPI.html""")
	
	parser.add_argument('output', nargs='?', type=argparse.FileType('w', encoding='UTF-8'),
					 default=sys.stdout, 
					 help="""Provide a file name [csv], or a keep it blank and the content is sent to STDOUT""")

	group = parser.add_mutually_exclusive_group()
	group.add_argument('--csv-header', dest="header", action='store_true')
	group.add_argument('--no-csv-header', dest="header", action='store_false')

	parser.set_defaults(header=True)

	args = parser.parse_args()
	main(file_input=args.input,
		 save=args.output,
		 header=args.header)