Convert JSON to environment variables for C# application settings

main.py

import argparse
import json
import re
import sys
from json.decoder import JSONDecodeError

MIN_ARGS = 2
ERROR_MIN_ARGS = 1
ERROR_FILE_FORMAT = 2


def is_valid_env_name(v):
    if not v:
        return False
    return re.match(r"^[a-zA-Z0-9_]+$", v)


def json2cs_env(obj, acc):
    if isinstance(obj, dict):
        for k in obj.keys():
            if not is_valid_env_name(k):
                raise ValueError(f"{k} cannot be converted into env variable")
            json2cs_env(obj[k], (acc + "__" + k if acc else k).upper())
    elif isinstance(obj, list):
        if len(obj) > 0:
            for index, _ in enumerate(obj):
                json2cs_env(obj[index], acc + "__" + str(index))
    else:
        first_part = f"{acc}="
        if obj is None:
            print(first_part)
        elif isinstance(obj, int):
            print(f"{first_part}{obj}")
        else:
            print(f'{first_part}"{obj}"')


def init():
    args_s = sys.argv
    if len(args_s) < MIN_ARGS:
        print("Need 2 arguments.")
        exit(ERROR_MIN_ARGS)
    _, i_file = sys.argv
    acc = ''
    f = None
    try:
        f = open(i_file)
        f_json = json.loads(f.read())
        json2cs_env(f_json, acc)
    except IOError:
        print("Input file accessible")
        exit(ERROR_FILE_FORMAT)
    except JSONDecodeError:
        print("Invalid json format on input file")
    finally:
        f.close()
    exit(0)

# Example usage: json2csenv.py filename.json
if __name__ == '__main__':
    init()