FastAPI sample app

A sample Python webapp that intends to showcase best practises regarding:

• most importantly a great http server (FastAPI)
• project structure
• all-around asynchronous IO
• config management
• dependency injection (provided by FastAPI)
• input validation (provided by FastAPI)
• unit and integration testing
• code style (flake8, isort)
• package management (Poetry)

How to run the app

Clone the repo:

$ git clone https://github.com/peterdeme/python-sample-app.git

Install Poetry if you haven't already. This project requires 1.0 which is currently in beta as of November 2019.

$ curl -sSL https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py | POETRY_VERSION=1.0.0b4 python

Create your own configuration from the template:

$ cp .env-template .env

Setup the Postgresql connection string in .env file. The default connection string points to a local Dockerized instance which you can easily pull up with:

$ docker-compose up -d pgsql

Initialize the database schema:

$ poetry run alembic upgrade head

Finally, run the app:

$ poetry run python -m app.app

In another cmd window test if it works:

$ curl http://localhost:8000/api/v1/articles && echo

Or just open the above URL in a browser.

Debug the app

Use the following interpeter in your IDE:

$ poetry run which python

Here's a sample debug config for VS Code users:

.vscode/launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch app",
            "type": "python",
            "request": "launch",
            "module": "app.app"
        }
    ]
}

Production use case

In production you'll most probably want to run a webapp in Docker. This repository contains a Dockerfile which aims to be a good example for a production service. You can try it locally:

$ docker-compose up

As per the official recommendation, the app uses Gunicorn as a green "worker manager" which spawns Uvicorn worker processes.

Linting and testing

Type check:

$ poetry run mypy app --config-file tox.ini

Autofix flake8 issues with autopep8:

$ poetry run autopep8 -r -i .

Sort imports:

$ poetry run isort -rc .

Run tests:

$ poetry run pytest