#cli.py

from argparse import Action, ArgumentParser

class DriverAction(Action):
	def __call__(self,parser,namespace,values,option_string=None):
		driver,destination = values
		namespace.driver = driver.lower()
		namespace.destination = destination

def create_parser():
	parser=ArgumentParser(description="""
    Back up PostgreSQL databases locally or to AWS S3.
    """)
	parser.add_argument("url", help="URL of database to backup")
        parser.add_argument("--driver",
    help="how & where to store backup",
        nargs=2,
        action=DriverAction,
        required=True)
	return parser

def main():
	import boto3
	from pgbackup import pgdump,storage
	
	args=create_parser().parse_args()
	dump=pgdump.dump(args.url)
	if args.driver == 's3':
		storage.s3(client,dump.stdout,args.destination,'example.sql')
	else:
		outfile=open(args.destination,'wb')
		storage.local(dump.stdout, outfile)