Django with Docker-2

This is a step-by-step tutorial that details how to configure Django to run on Docker with Postgres. For production environments, we'll add on Nginx and Gunicorn. We'll also take a look at how to serve Django static and media files via Nginx.

Dependencies:

1. Django v3.0.7
2. Docker v19.03.8
3. Python v3.8.3

Django on Docker Series:

1. Dockerizing Django with Postgres, Gunicorn, and Nginx (this article!)
2. Securing a Containerized Django Application with Let's Encrypt
3. Deploying Django to AWS with Docker and Let's encrypt

Project Setup

Create a new project directory along with a new Django project:

$ mkdir django-on-docker && cd django-on-docker $ mkdir app && cd app $ python3.8 -m venv env $ source env/bin/activate (env)$ pip install django==3.0.7 (env)$ django-admin.py startproject hello_django . (env)$ python manage.py migrate (env)$ python manage.py runserver

Feel free to swap out virtualenv and Pip for Poetry or Pipenv.

Navigate to http://localhost:8000/ to view the Django welcome screen. Kill the server and exit from the virtual environment once done. We now have a simple Django project to work with.

Create a requirements.txt file in the "app" directory and add Django as a dependency:

Django==3.0.7

Since we'll be moving to Postgres, go ahead and remove the db.sqlite3 file from the "app" directory.

Your project directory should look like:

└── app ├── hello_django │   ├── __init__.py │   ├── asgi.py │   ├── settings.py │   ├── urls.py │   └── wsgi.py ├── manage.py └── requirements.txt

Docker

Install Docker, if you don't already have it, then add a Dockerfile to the "app" directory:

# pull official base image FROM python:3.8.3-alpine # set work directory WORKDIR /usr/src/app # set environment variables ENV PYTHONDONTWRITEBYTECODE 1 ENV PYTHONUNBUFFERED 1 # install dependencies RUN pip install --upgrade pip COPY ./requirements.txt . RUN pip install -r requirements.txt # copy project COPY . .

So, we started with an Alpine-based Docker image for Python 3.8.3. We then set a working directory along with two environment variables:

1. PYTHONDONTWRITEBYTECODE: Prevents Python from writing pyc files to disc (equivalent to python -B option)
2. PYTHONUNBUFFERED: Prevents Python from buffering stdout and stderr (equivalent to python -u option)

Finally, we updated Pip, copied over the requirements.txt file, installed the dependencies, and copied over the Django project itself.

Review Docker for Python Developers for more on structuring Dockerfiles as well as some best practices for configuring Docker for Python-based development.

Next, add a docker-compose.yml file to the project root:

version: '3.7' services: web: build: ./app command: python manage.py runserver 0.0.0.0:8000 volumes: - ./app/:/usr/src/app/ ports: - 8000:8000 env_file: - ./.env.dev

Review the Compose file reference for info on how this file works.

Update the SECRET_KEY, DEBUG, and ALLOWED_HOSTS variables in settings.py:

SECRET_KEY = os.environ.get("SECRET_KEY") DEBUG = int(os.environ.get("DEBUG", default=0)) # 'DJANGO_ALLOWED_HOSTS' should be a single string of hosts with a space between each. # For example: 'DJANGO_ALLOWED_HOSTS=localhost 127.0.0.1 [::1]' ALLOWED_HOSTS = os.environ.get("DJANGO_ALLOWED_HOSTS").split(" ")

Then, create a .env.dev file in the project root to store environment variables for development:

DEBUG=1 SECRET_KEY=foo DJANGO_ALLOWED_HOSTS=localhost 127.0.0.1 [::1]

Build the image:

$ docker-compose build

Once the image is built, run the container:

$ docker-compose up -d

Navigate to http://localhost:8000/ to again view the welcome screen.

Check for errors in the logs if this doesn't work via docker-compose logs -f.