# -------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for
# license information.
# --------------------------------------------------------------------------
from asyncio import Condition, Lock
from datetime import datetime, timedelta
from typing import ( # pylint: disable=unused-import
cast,
Tuple,
)
import six
from msrest.serialization import TZ_UTC
from .utils import create_access_token
[docs]class CommunicationUserCredential(object):
"""Credential type used for authenticating to an Azure Communication service.
:param str token: The token used to authenticate to an Azure Communication service
:raises: TypeError
"""
ON_DEMAND_REFRESHING_INTERVAL_MINUTES = 2
def __init__(self,
token, # type: str
token_refresher=None
):
# type: (str) -> None
if not isinstance(token, six.string_types):
raise TypeError("token must be a string.")
self._token = create_access_token(token)
self._token_refresher = token_refresher
self._lock = Condition(Lock())
self._some_thread_refreshing = False
[docs] def get_token(self):
# type () -> ~azure.core.credentials.AccessToken
"""The value of the configured token.
:rtype: ~azure.core.credentials.AccessToken
"""
if not self._token_refresher or not self._token_expiring():
return self._token
should_this_thread_refresh = False
with self._lock:
while self._token_expiring():
if self._some_thread_refreshing:
if self._is_currenttoken_valid():
return self._token
self._wait_till_inprogress_thread_finish_refreshing()
else:
should_this_thread_refresh = True
self._some_thread_refreshing = True
break
if should_this_thread_refresh:
try:
newtoken = self._token_refresher()
with self._lock:
self._token = newtoken
self._some_thread_refreshing = False
self._lock.notify_all()
except:
with self._lock:
self._some_thread_refreshing = False
self._lock.notify_all()
raise
return self._token
def _wait_till_inprogress_thread_finish_refreshing(self):
self._lock.release()
self._lock.acquire()
def _token_expiring(self):
return self._token.expires_on - self._get_utc_now() <\
timedelta(minutes=self.ON_DEMAND_REFRESHING_INTERVAL_MINUTES)
def _is_currenttoken_valid(self):
return self._get_utc_now() < self._token.expires_on
@classmethod
def _get_utc_now(cls):
return datetime.now().replace(tzinfo=TZ_UTC)