Python/Flask tutorial sample for Visual Studio Code

• This sample contains the completed program from the tutorial, make sure to visit the link: Using Flask in Visual Studio Code. Intermediate steps are not included.
• It also contains the Dockerfile and uwsgi.ini files necessary to build a container with a production server. The resulting image works both locally and when deployed to Azure App Service. See Deploy Python using Docker containers.

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The startup.py file, for its part, is specifically for deploying to Azure App Service on Linux without containers. Because the app code is in its own module in the hello_app folder (which has an __init__.py), trying to start the Gunicorn server within App Service on Linux produces an "Attempted relative import in non-package" error. The startup.py file, therefore, is just a shim to import the app object from the hello_app module, which then allows you to use startup:app in the Gunicorn command line (see startup.txt).

Contributing

Contributions to the sample are welcome. When submitting changes, also consider submitting matching changes to the tutorial, the source file for which is tutorial-flask.md.

Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot automatically determines whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

Additional details

• This project has adopted the Microsoft Open Source Code of Conduct.
• For more information see the Code of Conduct FAQ or
• Contact opencode@microsoft.com with any additional questions or comments.

Added dependencies

pip install flask-wtf

pip install flask-sqlalchemy

pip install flask-migrate

To run the development server

source venv/bin/activate

export FLASK_APP=startup.py

flask run

To use Flask-Migrate

Only the first time.

flask db init

Generate migration script. the -m message is optional.

flask db migrate -m "users table"

Apply changes in the database

flask db upgrade

After updating the database uri, runupgrade again, so the database will be created in the remote server.

Start the python interpreter with all the flask dependencies of your app installed

flask shell

Troubleshooting with Database URI

Right now the URI is hardcoded. Follow this advice to fix the string format in the migrations/env.py file. (Flask issue, SQLAlchemy works) Link 1

Link 2

Link 3

Test command on independent script:

print(engine_azure.table_names())

output:

2020-05-18 01:42:24,631 INFO sqlalchemy.engine.base.Engine ('dbo', 'BASE TABLE') ['alembic_version', 'post', 'user']

NExt step May 17

• Commit changes to master and verify with pipeline deployment (merge branch & push to origin)

• but before, upgrade requirements.txt, even if the database is not visibly working in the app, the imports would break.

ENV VARIABLES

Get connection string

az storage account show-connection-string --name domingostorage9898

Set connection string for the storage account in your console.

export AZURE_STORAGE_CONNECTION_STRING="DefaultEndpoints....=="