import os
import sys


def read_variable(variable_name, *, fail_on_missing=True):
    value = os.environ.get(variable_name)
    if fail_on_missing and (value == '' or value is None):
        raise Exception('Environment variable ' + variable_name + ' is not set')

    return value


def is_min_version(version, system_version=None):
    if system_version is None:
        system_version = sys.version_info

    version_split = str(version).split('.')

    try:
        major_expected = int(version_split[0])
        minor_expected = int(version_split[1])
    except ValueError:
        print("Couldn't parse version: " + version)
        return False

    return (system_version[0] == major_expected) and (system_version[1] >= minor_expected)