from ..backend import KeyringBackend
from ..errors import NoKeyringError


class Keyring(KeyringBackend):
    """
    Keyring that raises error on every operation.

    >>> kr = Keyring()
    >>> kr.get_password('svc', 'user')
    Traceback (most recent call last):
    ...
    keyring.errors.NoKeyringError: ...No recommended backend...
    """

    priority = 0

    def get_password(self, service, username, password=None):
        msg = (
            "No recommended backend was available. Install a recommended 3rd "
            "party backend package; or, install the keyrings.alt package if "
            "you want to use the non-recommended backends. See "
            "https://pypi.org/project/keyring for details."
        )
        raise NoKeyringError(msg)

    set_password = delete_password = get_password  # type: ignore
