import contextlib
import subprocess
import tempfile


@contextlib.contextmanager
def authfile(username, password):
    auth = dict(username=username, password=password)
    with tempfile.TemporaryDirectory() as tempdir:
        auth_file = os.path.join(tempdir, 'auth.json')
        with open(auth_file, 'w') as fd:
            json.dump(auth, fd)

        yield auth_file


def main():
    username = "foo"
    password = "bar"
    auth_file = authfile(username, password)
    subprocess.check_call(['prog', '--autfile', auth_file])