arghelper.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import argparse
import os


def inputfile(path):
    if not path.endswith(".csv"):
        raise argparse.ArgumentTypeError("argument "
                                         "filename must be of type *.csv")
    return path


def check_range(arg):
    try:
        value = int(arg)
    except ValueError as err:
        raise argparse.ArgumentTypeError(str(err))
    if value < 1 or value > 3:
        message = "Expected (1, 2 or 3), got value = {}".format(value)
        raise argparse.ArgumentTypeError(message)
    return value


def inputdir(parser, path):
    if not os.path.isdir(path):
        message = "directory:{0} is not a valid path".format(path)
        parser.error(message)
    elif os.access(path, os.R_OK):
        return path
    else:
        message = "directory:{0} is not a readable directory".format(path)
        raise argparse.ArgumentError(message)