wpa_passphrase with pure python

import sys
from argparse import ArgumentParser
from binascii import hexlify
from hashlib import pbkdf2_hmac


CONFIG = """
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network={{
        ssid="{ssid}"
        #psk="{password}"
        psk={psk}
        proto=RSN
        key_mgmt=WPA-PSK
        pairwise=CCMP
        group=CCMP
}}
""".lstrip()


def gen_psk(ssid, password):
    password, ssid = map(str.encode, (password, ssid))
    hash = pbkdf2_hmac('sha1', password, ssid, 4096, 32)
    return hexlify(hash).decode()


def main(ssid, password):
    if not sys.stdin.isatty() and password:
        print('Which password should I take? From stdin or the argument?', file=sys.stderr)
        return 2
    if not sys.stdin.isatty() and not password:
        password = sys.stdin.readline().rstrip()
    try:
        psk = gen_psk(ssid, password)
        print(CONFIG.format(ssid=ssid, password=password, psk=psk))
    except Exception as e:
        print(e, file=sys.stderr)
        return 1


if __name__ == '__main__':
    parser = ArgumentParser()
    parser.add_argument('ssid', help='SSID of hotspot')
    parser.add_argument('password', default='', nargs='?', help='Password of hotspot')
    args = parser.parse_args()
    retval = main(**vars(args))
    sys.exit(retval)