argparse2

Works just like argparse but also automatically supports environment vars.

For example, myapp:

#!/usr/bin/env python
from argparse2 import EnvParser

if __name__ == '__main__':
    parser = EnvParser('myapp')
    parser.add_argument('-a', '--address', default='127.0.0.1', help='address to bind')
    parser.add_argument('-p', '--port', default='8080', help='port to listen')
    args = parser.parse_args()
    print('listening to {}:{}'.format(args.address, args.port))

No arguments, flags, or environment vars:

./myapp.py
listening to 127.0.0.1:8080

A flag:

./myapp --port 6060
listening to 127.0.0.1:6060

A flag and an environment var:

MYAPP_ADDRESS=0.0.0.0 ./myapp --port 6060
listening to 0.0.0.0:6060

A flag overriding an environment var:

MYAPP_ADDRESS=0.0.0.0 ./myapp --address 192.168.1.21
listening to 192.168.1.21:8080

We also add the environment vars to the help texts:

./myapp --help
usage: myapp [-h] [-a ADDRESS] [-p PORT]

optional arguments:
  -h, --help            show this help message and exit, MYAPP_HELP=help
  -a ADDRESS, --address ADDRESS
                        address to bind, MYAPP_ADDRESS=address
  -p PORT, --port PORT  port to listen, MYAPP_PORT=port

russellballestrini/argparse2

argparse2