CreateP4Config.py #3

#!/Library/Frameworks/Python.framework/Versions/3.4/bin/python3
__author__ = 'sknop'

import sys
import os
import os.path
from collections import OrderedDict

# expect
# P4PORT
# P4ROOT
# P4CLIENT
# P4CLIENT root

P4CONFIG='.p4'
P4ROOT='.'


def update_config(filename, params):
    read_params = OrderedDict()
    with open(filename) as f:
        # understand and preserve comments?
        for line in f:
            (k,v) = line.split('=')
            read_params[k] = v

    read_params.update(params)

    create_config(filename, read_params)


def create_config(filename, params):
    with open(filename, "w") as f:
        for (k,v) in params.items():
            print("{}={}".format(k,v),file=f)


def process_config(params):
    p4config = params.pop('P4CONFIG', P4CONFIG)
    p4root = params.pop('P4ROOT', P4ROOT)

    filename = os.path.join(p4root, p4config)
    if os.path.exists(filename):
        update_config(filename, params)
    else:
        # ensure the directory exists
        # note - for Python 2 remove exist_ok and replace with try - catch(FileExistError) block
        os.makedirs(p4root, exist_ok=True)
        create_config(filename, params)


if __name__ == '__main__':
    params = OrderedDict((a.split('=') for a in sys.argv[1:]))
    print(params)

    process_config(params)