import random
import hashlib
import time


def get_random_string(length=12,
                      allowed_chars='abcdefghijklmnopqrstuvwxyz'
                      'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'):
    """
    See also:
        https://github.com/rs/xid (globally unique id generator)
        https://stackoverflow.com/questions/41354205/how-to-generate-a-unique-auth-token-in-python
    """
    random.seed(
        hashlib.sha256(
            ("%s%s%s" % (
                random.getstate(),
                time.time(),
                'O_O-SECRET_KEY')).encode('utf-8')
        ).digest())
    return ''.join(random.choice(allowed_chars) for i in range(length))