Example of a scalable Flask API

This the back-end of the Arborator-Grew redevelopement of the arborator-server.

Useful Resources

Before starting to dive deep in the code, you should refer to these following important resources :

• Flask-RESTx : How to build a restful server with python
• Some Flask good practives : How to use static typing and testing procedure with flask.

Setting the environment config

Create a .flaskenv file with the following config

FLASK_ENV=dev|prod|test

Setting the python virtual environment

Preferably, first create a virtualenv and activate it, perhaps with the following command:

virtualenv -p python3 venv
source venv/bin/activate

Next, run

pip install -r requirements.txt

to get the dependencies.

Manage the database

If first time, initialize the database

python manage.py seed_db

Type "Y" to accept the message (which is just there to prevent you accidentally deleting things -- it's just a local SQLite database)

Handling superadmin

For adding a superadmin, run the following command

python manage.py add_super_admin --username $username

For removing a superadmin

python manage.py remove_super_admin --username $username

Run the app for local development

In .flaskenv, set the FLASK_ENV to dev and FLASK_APP to wsgi.py

FLASK_ENV=dev
FLASK_APP=wsgi.py

Then, you can run the app with flask and a secured certificate protocole.

flask run --cert=adhoc

We need to specify cert because we use Google and Github credentials login and it required an https connection.

Running tests

To run the test suite, simply pip install it and run from the root directory like so

pip install pytest
pytest

Deploy the app in production

Set the environment

On the server, create the project folder

mkdir /var/www/flask_api_example

In the project folder, create a python virtual environment

python -m venv ven

Install the python packages requirements

pip install -r requirements.txt

In .flaskenv, set FLASK_ENV to prod

FLASK_ENV=prod

Initialize the DB (or paste an existant one)

python migrate.py seed_db

Proxy setting

If needed to, allow the folder access to the server user that will have control the app

sudo chown -Rf <admin>:<group> /var/www/flask_api_example/

source : https://www.digitalocean.com/community/tutorials/how-to-serve-flask-applications-with-uswgi-and-nginx-on-ubuntu-18-04

Navigate to the posted URL in your terminal to be greeted with Swagger, where you can test out the API.