Flask

Flask is a lightweight WSGI web application framework. It is designed to make getting started quick and easy, with the ability to scale up to complex applications. It began as a simple wrapper around Werkzeug and Jinja and has become one of the most popular Python web application frameworks.

License

All relevant legal information can be found here

https://www.palletsprojects.com/governance/licenses-and-copyright/

Installation

The name of the application you are going to set up is called flask_rest_client. If you wish to use another name make sure to replace flask_rest_client in all of the following steps with the name of your choice.

Clone the template application

[isabell@stardust ~]$ mkdir flask_rest_client
[isabell@stardust ~]$ git clone https://github.com/bwiessneth/flask_rest_client.git flask_rest_client/
[isabell@stardust ~]$

This repository comes with all the files you need for this tutorial. Alternatively download the repository as a ZIP and extract it.

Setup python environment and install required packages

You definitely want to create a isolated python environment. That way the required packages you are going to install with pip are encapsulated form your systemwide python installation. For more info check https://virtualenv.pypa.io/en/latest/

[isabell@stardust ~]$ cd flask_rest_client
[isabell@stardust flask_rest_client]$ virtualenv -p python3 ENV
[isabell@stardust flask_rest_client]$ source ENV/bin/activate
(ENV) [isabell@stardust flask_rest_client]$ pip install -r deploy/requirements.txt
(ENV) [isabell@stardust flask_rest_client]$

You can activate your new python environment like this:

[isabell@stardust flask_rest_client]$ source ENV/bin/activate
(ENV) [isabell@stardust flask_rest_client]$

Once you're done playing with it, deactivate it with the following command:

(ENV) [isabell@stardust flask_rest_client]$ deactivate
[isabell@stardust flask_rest_client]$

Setup nginx

Note

flask_rest_client is running on port 1027.

Create an endpoint where the app will be served from. I chose that my application should be served using http under /flask_rest_client using port 1027. That way your default web endpoint / will be served by apache and display what's inside ~/html.

On uberspace you'll want to use the built-in uberspace tool.

[isabell@stardust ~]$ uberspace web backend set /flask_rest_client --http --port 1027

Start your application

Using Werkzeug for development

You can use Werkzeug which get's shipped with Flask to spin up a small development server. But be aware: Do not use it in a production deployment. For more info head to https://www.palletsprojects.com/p/werkzeug/.

To start Werkzeug execute run_werkzeug.sh from within the application directory. It enables the virtual python environment and uses executes app.py.

Once its running try to access it at https://isabell.uber.space/flask_rest_client. Stop it by pressing Ctrl + C.

[isabell@stardust flask_rest_client]$ ./run_werkzeug.sh
 ℹ * Serving Flask app "app" (lazy loading)
 ℹ * Environment: production
     WARNING: This is a development server. Do not use it in a production deployment.
     Use a production WSGI server instead.
 ℹ * Debug mode: on
 ℹ * Running on http://0.0.0.0:1027/ (Press CTRL+C to quit)
 ℹ * Restarting with stat
 ℹ * Debugger is active!
 ℹ * Debugger PIN: 262-417-928
^C
[isabell@stardust flask_rest_client]$

UWSGI

A more suited approach to serve your application would be to use uWSGI. The uWSGI project aims at developing a full stack for building hosting services. For more info head to https://uwsgi-docs.readthedocs.io/en/latest/.

To serve your application via uWSGI execute the run_uwsgi.sh script from within the application directory. It enables the virtual python environment and uses the configuration parameter found in uwsgi.ini. The application is loaded from uwsgi_app.py, which justs imports the app object from app.py.