That exception looks like Flask-Uploads is trying to from werkzeug import secure_filename which should be from werkzeug.utils import secure_filename, as per your own code.

Going by the Flask-Uploads github repo this appears to have been fixed 12 months ago.

I'd try pip install -U flask-uploads in your virtual environment, to ensure the latest version.

EDIT:

As @mattficke points out, the PyPi version is dated, and there's not a more recent release on the repo. Turns out you can install directly based on a commit hash, so for the latest (at the time of writing this):

pip install git+https://github.com/maxcountryman/flask-uploads.git@f66d7dc

Or in a requirements.txt:

git+https://github.com/maxcountryman/flask-uploads.git@f66d7dc

Then pip install -r requirements.txt.

Which works wonders:

>>> from flask_uploads import UploadSet,configure_uploads,IMAGES,DATA,ALL
>>> # No Exception

In flask_uploads.py

Change

from werkzeug import secure_filename,FileStorage

to

from werkzeug.utils import secure_filename
from werkzeug.datastructures import  FileStorage

With this, it worked, thanks:

pip install werkzeug==0.16.0

DB: sqlite:////home/centos/airflow/airflow.db

[2020-02-07 12:02:02,523] {db.py:368} INFO - Creating tables

you version control via requirements.txt

https://github.com/maxcountryman/flask-uploads/issues/33

Curious what you're using for storage since heroku containers are ephemeral