Azure Flask app | Azure SQL - pyodbc.OperationalError Timeout with load_dotenv() - flask

Question

I have a Flask app running on Azure with a connection to an Azure SQL db and after the below developments I can't access the database any longer.
Here is what I recently added :
created a .env file to secure the connection string
added a .gitignore
added the following to my main.py:
connection_string = textwrap.dedent(f'''
Driver={driver};
Server={os.getenv("SERVER")};
Database={os.getenv("DB_NAME")};
Uid={os.getenv("DB_USER")};
Pwd={os.getenv("PASSWORD")};
Encrypt=yes;
TrustServerCertificate=no;
Connection Timeout=30;
''')
I've also added the following to run in production :
if __name__ == '__main__':
from waitress import serve
serve(app, host="0.0.0.0", port=8080)
It works perfectly locally but as soon as I deploy it on Azure, I have issues with the docker deployment in the background. It seems the connection strings params are not recognized from the following error (from Kudu) :
Warning
2021-10-15T12:42:51.4960727
[2021-10-15 12:42:51 +0000] [40] [ERROR] Exception in worker process
Ok
2021-10-15T12:42:51.4961108
Traceback (most recent call last):
Ok
2021-10-15T12:42:51.4961177
File "/tmp/8d98fd8a8763182/antenv/lib/python3.8/site-packages/gunicorn/arbiter.py", line 589, in spawn_worker
Ok
2021-10-15T12:42:51.4961354
worker.init_process()
Ok
2021-10-15T12:42:51.4961403
File "/tmp/8d98fd8a8763182/antenv/lib/python3.8/site-packages/gunicorn/workers/base.py", line 134, in init_process
Ok
2021-10-15T12:42:51.4961451
self.load_wsgi()
Ok
2021-10-15T12:42:51.4961495
File "/tmp/8d98fd8a8763182/antenv/lib/python3.8/site-packages/gunicorn/workers/base.py", line 146, in load_wsgi
Ok
2021-10-15T12:42:51.4961542
self.wsgi = self.app.wsgi()
Ok
2021-10-15T12:42:51.4961586
File "/tmp/8d98fd8a8763182/antenv/lib/python3.8/site-packages/gunicorn/app/base.py", line 67, in wsgi
Ok
2021-10-15T12:42:51.4961638
self.callable = self.load()
Ok
2021-10-15T12:42:51.4961682
File "/tmp/8d98fd8a8763182/antenv/lib/python3.8/site-packages/gunicorn/app/wsgiapp.py", line 58, in load
Ok
2021-10-15T12:42:51.4961729
return self.load_wsgiapp()
Ok
2021-10-15T12:42:51.4961772
File "/tmp/8d98fd8a8763182/antenv/lib/python3.8/site-packages/gunicorn/app/wsgiapp.py", line 48, in load_wsgiapp
Ok
2021-10-15T12:42:51.496182
return util.import_app(self.app_uri)
Ok
2021-10-15T12:42:51.4961864
File "/tmp/8d98fd8a8763182/antenv/lib/python3.8/site-packages/gunicorn/util.py", line 359, in import_app
Ok
2021-10-15T12:42:51.496191
mod = importlib.import_module(module)
Ok
2021-10-15T12:42:51.4961956
File "/opt/python/3.8.6/lib/python3.8/importlib/__init__.py", line 127, in import_module
Ok
2021-10-15T12:42:51.4962002
return _bootstrap._gcd_import(name[level:], package, level)
Ok
2021-10-15T12:42:51.496308
File "", line 1014, in _gcd_import
Ok
2021-10-15T12:42:51.496315
File "", line 991, in _find_and_load
Ok
2021-10-15T12:42:51.4963197
File "", line 975, in _find_and_load_unlocked
Ok
2021-10-15T12:42:51.4963244
File "", line 671, in _load_unlocked
Ok
2021-10-15T12:42:51.496329
File "", line 783, in exec_module
Ok
2021-10-15T12:42:51.4963337
File "", line 219, in _call_with_frames_removed
Ok
2021-10-15T12:42:51.4963383
File "/tmp/8d98fd8a8763182/main.py", line 104, in
Ok
2021-10-15T12:42:51.4965707
con, cur = AZconnect()
Ok
2021-10-15T12:42:51.496577
File "/tmp/8d98fd8a8763182/main.py", line 91, in AZconnect
Ok
2021-10-15T12:42:51.4965817
con: pyodbc.Connection = pyodbc.connect(connection_string)
Warning
2021-10-15T12:42:51.4965863
pyodbc.OperationalError: ('HYT00', '[HYT00] [Microsoft][ODBC Driver 17 for SQL Server]Login timeout expired (0) (SQLDriverConnect)')
I'm quite sure I did something wrong with the .env and load_dotenv() but I don't see where.

Answer 1

I understood my mistake ; .gitignore prenvented to use the .env file as it should hence the environment variable couldn't be set.
I then set these variable in Azure application settings and it worked just fine :