Source code for azure.identity.aio._credentials.chained

# ------------------------------------
# Copyright (c) Microsoft Corporation.
# Licensed under the MIT License.
# ------------------------------------
import asyncio
import logging
from typing import TYPE_CHECKING

from azure.core.exceptions import ClientAuthenticationError
from .base import AsyncCredentialBase
from ... import CredentialUnavailableError
from ..._credentials.chained import _get_error_message

if TYPE_CHECKING:
    from typing import Any, Optional
    from azure.core.credentials import AccessToken
    from azure.core.credentials_async import AsyncTokenCredential

_LOGGER = logging.getLogger(__name__)


[docs]class ChainedTokenCredential(AsyncCredentialBase): """A sequence of credentials that is itself a credential. Its :func:`get_token` method calls ``get_token`` on each credential in the sequence, in order, returning the first valid token received. :param credentials: credential instances to form the chain :type credentials: :class:`azure.core.credentials.AsyncTokenCredential` """ def __init__(self, *credentials: "AsyncTokenCredential") -> None: if not credentials: raise ValueError("at least one credential is required") self._successful_credential = None # type: Optional[AsyncTokenCredential] self.credentials = credentials
[docs] async def close(self): """Close the transport sessions of all credentials in the chain.""" await asyncio.gather(*(credential.close() for credential in self.credentials))
[docs] async def get_token(self, *scopes: str, **kwargs: "Any") -> "AccessToken": """Asynchronously request a token from each credential, in order, returning the first token received. If no credential provides a token, raises :class:`azure.core.exceptions.ClientAuthenticationError` with an error message from each credential. .. note:: This method is called by Azure SDK clients. It isn't intended for use in application code. :param str scopes: desired scopes for the access token. This method requires at least one scope. :raises ~azure.core.exceptions.ClientAuthenticationError: no credential in the chain provided a token """ history = [] for credential in self.credentials: try: token = await credential.get_token(*scopes, **kwargs) _LOGGER.info("%s acquired a token from %s", self.__class__.__name__, credential.__class__.__name__) self._successful_credential = credential return token except CredentialUnavailableError as ex: # credential didn't attempt authentication because it lacks required data or state -> continue history.append((credential, ex.message)) _LOGGER.info("%s - %s is unavailable", self.__class__.__name__, credential.__class__.__name__) except Exception as ex: # pylint: disable=broad-except # credential failed to authenticate, or something unexpectedly raised -> break history.append((credential, str(ex))) _LOGGER.warning( '%s.get_token failed: %s raised unexpected error "%s"', self.__class__.__name__, credential.__class__.__name__, ex, exc_info=_LOGGER.isEnabledFor(logging.DEBUG), ) break attempts = _get_error_message(history) message = self.__class__.__name__ + " failed to retrieve a token from the included credentials." + attempts raise ClientAuthenticationError(message=message)