AssertionError importing from azure.identity in Azure Function

[Valdeminas]

I'm trying to use azure keyvault in my python azure function.

When importing azure.keyvault.secrets, everything works fine.

However, when I add from azure.identity import DefaultAzureCredential, build fails with (slightly redacted for privacy):

[2021-07-29T12:41:02.772Z] Result: Failure
Exception: AssertionError:
Stack:   File "C:\Users\Username\AppData\Roaming\npm\node_modules\azure-functions-core-tools\bin\workers\python\3.9/WINDOWS/X64\azure_functions_worker\dispatcher.py", line 301, in _handle__function_load_request
    func = loader.load_function(
  File "C:\Users\Username\AppData\Roaming\npm\node_modules\azure-functions-core-tools\bin\workers\python\3.9/WINDOWS/X64\azure_functions_worker\utils\wrappers.py", line 40, in call
    return func(*args, **kwargs)
  File "C:\Users\Username\AppData\Roaming\npm\node_modules\azure-functions-core-tools\bin\workers\python\3.9/WINDOWS/X64\azure_functions_worker\loader.py", line 83, in load_function
    mod = importlib.import_module(fullmodname)
  File "C:\Users\Username\AppData\Local\Programs\Python\Python39\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 850, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\Balance\__init__.py", line 5, in <module>
    from ..shared_code import utility
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\shared_code\utility.py", line 4, in <module>
    from azure.identity import DefaultAzureCredential
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\azure\identity\__init__.py", line 10, in <module>
    from ._credentials import (
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\azure\identity\_credentials\__init__.py", line 5, in <module>
    from .authorization_code import AuthorizationCodeCredential
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\azure\identity\_credentials\authorization_code.py", line 8, in <module>   
    from .._internal.aad_client import AadClient
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\azure\identity\_internal\__init__.py", line 52, in <module>
    from .interactive import InteractiveCredential
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\azure\identity\_internal\interactive.py", line 20, in <module>
    from .msal_credentials import MsalCredential
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\azure\identity\_internal\msal_credentials.py", line 11, in <module>       
    from .._persistent_cache import _load_persistent_cache, TokenCachePersistenceOptions
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\azure\identity\_persistent_cache.py", line 9, in <module>
    import msal_extensions
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\msal_extensions\__init__.py", line 12, in <module>
    from .cache_lock import CrossPlatLock
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\msal_extensions\cache_lock.py", line 5, in <module>
    import portalocker
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\portalocker\__init__.py", line 4, in <module>
    from . import portalocker
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\portalocker\portalocker.py", line 10, in <module>
    import pywintypes
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\win32\lib\pywintypes.py", line 105, in <module>
    __import_pywin32_system_module__("pywintypes", globals())
  File "D:\Users\Username\Source\Repos\ProjectName\ProjectName\.venv\lib\site-packages\win32\lib\pywintypes.py", line 99, in __import_pywin32_system_module__    
    assert sys.modules[modname] is not old_mod
.

This stack overflow question seems to deal with the same issue, but sadly does not have an answer :(

[chlowell]

There's also an old issue on pywin32. I assume you're running this function locally on Windows with the Azure Functions CLI. This error doesn't repro in my environment with a function that imports DefaultAzureCredential and pywintypes. Can you share the output of pip freeze for your environment?

Here's mine for comparison:

azure-core==1.16.0
azure-functions==1.7.2
azure-identity==1.6.0
certifi==2021.5.30
cffi==1.14.6
charset-normalizer==2.0.3
cryptography==3.4.7
idna==3.2
msal==1.13.0
msal-extensions==0.3.0
portalocker==1.7.1
pycparser==2.20
PyJWT==2.1.0
pywin32==301
requests==2.26.0
six==1.16.0
urllib3==1.26.6

[aaronsmith1234]

We are having this same issue, and here is the pip freeze output;

azure-functions==1.7.2
azure-identity==1.6.0
azure-storage-blob==12.8.1
certifi==2021.5.30
cffi==1.14.6
charset-normalizer==2.0.3
cryptography==3.4.7
idna==3.2
isodate==0.6.0
msal==1.13.0
msal-extensions==0.3.0
msrest==0.6.21
numpy==1.21.1
oauthlib==3.1.1
portalocker==1.7.1
pycparser==2.20
PyJWT==2.1.0
pywin32==301
requests==2.26.0
requests-oauthlib==1.3.0
scipy==1.7.0
six==1.16.0
urllib3==1.26.6

[chlowell]

Interesting, same version of the pertinent libraries. Which Python? I installed your libraries (plus azure-core 1.16.0) in my environment (Python 3.7.9) and still don't get the error.

I should also add I'm using Azure Functions CLI 3.0.3477.

[aaronsmith1234]

3.9.2 64 bit Also, confirmed with co-worker that this is the line that is causing the error above.
from azure.identity import DefaultAzureCredential

[chlowell]

Do you see the same error in a fresh venv? I don't see it on 3.9 either.

[aaronsmith1234]

It did; we deleted and re-did the virutal environment. We were using the Azure Functions add-in for VSCode to create the boilerplate code for the function; not sure if that's the same as the CLI.

Here is the code (can't post the rest of function, sorry!) which results in an error

import logging

import azure.functions as func
from azure.identity import DefaultAzureCredential

def main(req: func.HttpRequest) -> func.HttpResponse:
    logging.info('Python HTTP trigger function processed a request.')
    return 1

Azure Functions Core Tools
Core Tools Version: 3.0.3477 Commit hash: 5fbb9a76fc00e4168f2cc90d6ff0afe5373afc6d (64-bit)
Function Runtime Version: 3.0.15584.0

Python 3.9.2 64 bit, requirements.txt

azure-functions==1.7.2
azure-identity==1.6.0
azure-storage-blob==12.8.1
certifi==2021.5.30
cffi==1.14.6
charset-normalizer==2.0.3
cryptography==3.4.7
idna==3.2
isodate==0.6.0
msal==1.13.0
msal-extensions==0.3.0
msrest==0.6.21
numpy==1.21.1
oauthlib==3.1.1
portalocker==1.7.1
pycparser==2.20
PyJWT==2.1.0
pywin32==301
requests==2.26.0
requests-oauthlib==1.3.0
scipy==1.7.0
six==1.16.0
urllib3==1.26.6