# ------------------------------------
# Copyright (c) Microsoft Corporation.
# Licensed under the MIT License.
# ------------------------------------
from datetime import datetime
import time
from azure.core.exceptions import ClientAuthenticationError
from .._constants import DEVELOPER_SIGN_ON_CLIENT_ID
from .._internal import InteractiveCredential, wrap_exceptions
try:
from typing import TYPE_CHECKING
except ImportError:
TYPE_CHECKING = False
if TYPE_CHECKING:
# pylint:disable=unused-import,ungrouped-imports
from typing import Any, Optional
[docs]class DeviceCodeCredential(InteractiveCredential):
"""Authenticates users through the device code flow.
When :func:`get_token` is called, this credential acquires a verification URL and code from Azure Active Directory.
A user must browse to the URL, enter the code, and authenticate with Azure Active Directory. If the user
authenticates successfully, the credential receives an access token.
This credential is primarily useful for authenticating a user in an environment without a web browser, such as an
SSH session. If a web browser is available, :class:`~azure.identity.InteractiveBrowserCredential` is more
convenient because it automatically opens a browser to the login page.
:param str client_id: client ID of the application users will authenticate to. When not specified users will
authenticate to an Azure development application.
:keyword str authority: Authority of an Azure Active Directory endpoint, for example "login.microsoftonline.com",
the authority for Azure Public Cloud (which is the default). :class:`~azure.identity.AzureAuthorityHosts`
defines authorities for other clouds.
:keyword str tenant_id: an Azure Active Directory tenant ID. Defaults to the "organizations" tenant, which can
authenticate work or school accounts. **Required for single-tenant applications.**
:keyword int timeout: seconds to wait for the user to authenticate. Defaults to the validity period of the
device code as set by Azure Active Directory, which also prevails when **timeout** is longer.
:keyword prompt_callback: A callback enabling control of how authentication
instructions are presented. Must accept arguments (``verification_uri``, ``user_code``, ``expires_on``):
- ``verification_uri`` (str) the URL the user must visit
- ``user_code`` (str) the code the user must enter there
- ``expires_on`` (datetime.datetime) the UTC time at which the code will expire
If this argument isn't provided, the credential will print instructions to stdout.
:paramtype prompt_callback: Callable[str, str, ~datetime.datetime]
:keyword AuthenticationRecord authentication_record: :class:`AuthenticationRecord` returned by :func:`authenticate`
:keyword bool disable_automatic_authentication: if True, :func:`get_token` will raise
:class:`AuthenticationRequiredError` when user interaction is required to acquire a token. Defaults to False.
:keyword cache_persistence_options: configuration for persistent token caching. If unspecified, the credential
will cache tokens in memory.
:paramtype cache_persistence_options: ~azure.identity.TokenCachePersistenceOptions
"""
def __init__(self, client_id=DEVELOPER_SIGN_ON_CLIENT_ID, **kwargs):
# type: (Optional[str], **Any) -> None
self._timeout = kwargs.pop("timeout", None) # type: Optional[int]
self._prompt_callback = kwargs.pop("prompt_callback", None)
super(DeviceCodeCredential, self).__init__(client_id=client_id, **kwargs)
@wrap_exceptions
def _request_token(self, *scopes, **kwargs):
# type: (*str, **Any) -> dict
# MSAL requires scopes be a list
scopes = list(scopes) # type: ignore
app = self._get_app(**kwargs)
flow = app.initiate_device_flow(scopes)
if "error" in flow:
raise ClientAuthenticationError(
message="Couldn't begin authentication: {}".format(flow.get("error_description") or flow.get("error"))
)
if self._prompt_callback:
self._prompt_callback(
flow["verification_uri"], flow["user_code"], datetime.utcfromtimestamp(flow["expires_at"])
)
else:
print(flow["message"])
if self._timeout is not None and self._timeout < flow["expires_in"]:
# user specified an effective timeout we will observe
deadline = int(time.time()) + self._timeout
result = app.acquire_token_by_device_flow(
flow, exit_condition=lambda flow: time.time() > deadline, claims_challenge=kwargs.get("claims")
)
else:
# MSAL will stop polling when the device code expires
result = app.acquire_token_by_device_flow(flow, claims_challenge=kwargs.get("claims"))
# raise for a timeout here because the error is particular to this class
if "access_token" not in result and result.get("error") == "authorization_pending":
raise ClientAuthenticationError(message="Timed out waiting for user to authenticate")
# base class will raise for other errors
return result