[BUG] azure-storage-blob incompatible with Python Functions 3.8

Investigative information

• Timestamp: May 14 2020 - 8:40:01 PM PST
• Function App name: jpwircur7u6mu
• Exception type Microsoft.Azure.WebJobs.Host.FunctionInvocationException
• HostInstanceId: d09b7b97-db9e-45c0-857c-2104a0d12a68
• InvocationId 03abef06-46c7-4243-80f6-36185725f329

Repro steps

1. Create a function using Python 3.8
2. Add the import: “from azure.storage.blob import BlobSasPermissions, generate_blob_sas”
3. Reference any of the storage functions

Similar issue was created here but closed. https://github.com/Azure/azure-sdk-for-python/issues/3623

Expected behavior

There should be no exception

Actual behavior

Will receive the following exception when running the function.

Microsoft.Azure.WebJobs.Host.FunctionInvocationException: Exception while executing function: Functions.MyFunctionName
 ---> Microsoft.Azure.WebJobs.Script.Workers.Rpc.RpcException: Result: Failure
Exception: ModuleNotFoundError: No module named 'azure.storage'
Stack:   File "/azure-functions-host/workers/python/3.6/LINUX/X64/azure_functions_worker/dispatcher.py", line 242, in _handle__function_load_request
    func_request.metadata.entry_point)
  File "/azure-functions-host/workers/python/3.6/LINUX/X64/azure_functions_worker/loader.py", line 66, in load_function
    mod = importlib.import_module(fullmodname)
  File "/usr/local/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/home/site/wwwroot/MyFunctionName/__init__.py", line 1, in <module>
    from azure.storage.blob import BlobSasPermissions, generate_blob_sas

Contents of the requirements.txt file:

--find-links wheelhouse
azure-storage-blob==12.3.1

[Hazhzeng]

Hi @JackStromberg,

To mitigate this issue, could you use func pack to resolve the dependencies on your local machine? This will generate a .zip file which contains .python_packages in it. Upload this zip file into storage account and use its SAS URL in WEBSITE_RUN_FROM_PACKAGE app setting should work.

[vrdmr]

@JackStromberg Could you confirm the following:

• When you do func start, what version of python does it call out?
• When you type python –version, what does it show?

The issue could be the modules version mismatch due to an update, which could be resolved by recreating python virtual environments.

rm -Recurse -Force .\.venv
python-3.8 -m venv .venv

Else, @Hazhzeng wrote a comprehensive list of diagnoses and mitigations in - Module not found issues Wiki, please let me know if that helps.