Docker'd Django

Django, Postgres, and Redis, all in Docker

This is a boilerplate repo intended for quickly starting a new Django project with PostgreSQL and Redis support, all running within Docker containers.

Multiple production hosting options are also included. See the Production Hosting section below for more information.

• Prerequisites
• Getting started
• Components
• Production Hosting
• Troubleshooting

Prerequisites

• Docker
• Pipenv
  • Make sure Python3 is available
  • Enables pipenv install to set up libraries locally for the editor to crawl. The Django container also uses Pipenv to install dependencies to encourage use of this new Python package management tool.

Getting started

1. Clone this repo
2. Delete the .git folder
   • rm -rf .git/
3. Create a new git repo
   • git init
   • git add .
   • git commit -m "Initial Commit"
4. Install Python dependencies in a Python3 virtual environment
   • pipenv install --three
5. Create a new Django project
   • pipenv run django-admin startproject appname _app/
6. Make the following changes to your Django project's settings.py:

# appname/settings.py
import os

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = os.getenv('DJANGO_SECRET_KEY')

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = os.getenv('DEBUG', False) == 'true'

# Enable traffic and form submissions from localhost and PROD_HOST_NAME
ALLOWED_HOSTS = ['localhost']
CSRF_TRUSTED_ORIGINS = ['http://localhost']

PROD_HOST_NAME = os.getenv('PROD_HOST_NAME', None)
if PROD_HOST_NAME:
    ALLOWED_HOSTS.append(PROD_HOST_NAME)
    CSRF_TRUSTED_ORIGINS.append(f'https://{PROD_HOST_NAME}')

# Configure whitenoise for static file hosting
INSTALLED_APPS = [
    # ...
    # See http://whitenoise.evans.io/en/latest/django.html#using-whitenoise-in-development
    "whitenoise.runserver_nostatic",
    "django.contrib.staticfiles",
    # ...
]

MIDDLEWARE = [
    # ...
    "django.middleware.security.SecurityMiddleware",
    # See http://whitenoise.evans.io/en/latest/django.html#enable-whitenoise
    "whitenoise.middleware.WhiteNoiseMiddleware",
    # ...
]

# Point Django to Docker-hosted Postgres
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': os.getenv('POSTGRES_USER'),
        'USER': os.getenv('POSTGRES_USER'),
        'PASSWORD': os.getenv('POSTGRES_PASSWORD'),
        'HOST': 'db',
        'PORT': 5432,
    }
}

# Set up static files
STATIC_ROOT = 'static'
# See http://whitenoise.evans.io/en/latest/django.html#enable-whitenoise
STATICFILES_STORAGE = "whitenoise.storage.CompressedManifestStaticFilesStorage"

# Redis cache support
# https://docs.djangoproject.com/en/4.0/topics/cache/#redis-1

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.redis.RedisCache',
        'LOCATION': 'redis://redis:6379/1',
    }
}
SESSION_ENGINE = 'django.contrib.sessions.backends.cache'
SESSION_CACHE_ALIAS = 'default'

7. Update the .env file to specify values for the environment variables defined within
8. Do a global search of all files here for "appname" and replace it with the actual name of your app
9. Start Django for development at http://localhost:8000
   • docker-compose up

Components

Dockerfile

Builds the Django container. The container is built from a standard python Docker image and will run Django's colletstatic when being built.

docker-compose.yml + docker-compose.dev.yml

Use ./start-dev.sh to start Django for development. This will spin up three containers: the above container for Django, one for PostgreSQL, and one for Redis.

Django can be accessed in DEBUG mode directly from http://localhost:8000 during development. The Gunicorn workers are set to reload when file changes are detected.

Postgres can also be directly accessed at localhost:5432 using the credentials you specified in the .env file.

docker-compose.yml + docker-compose.prod.yml

See the Production Hosting section below for more information.

Use ./start-dev.sh to start Django for production. You can also run ./update-prod-django.sh whenever you need to deploy a new build.

Pipfile/Pipfile.lock

Includes Python packages needed to make Django, Postgre, and Redis work together.

.env

Contains environment variables for the containers. Several variables are included for configuring Postgres and Django secrets.

.dockerignore

Defines files that Docker should never include when building the Django image.

.editorconfig

Defines some common settings to help ensure consistency of styling across files.

.flake8

Configures the flake8 Python linter. Includes a few common settings to my personal preferences.

.vscode/settings.json

Helps configure the Python plugin to lint with flake8. A placeholder Python interpreter setting is left in to simplify pointing to the local virtual environment created with Pipenv.

_app/gunicorn.cfg.py

Defines settings for gunicorn, including a port binding, workers, and a gunicorn-specific error log.

_caddy/Caddyfile

Establishes a reverse-proxy to Django, and serves Django static files using Caddy. See Production Hosting below for more info.

Production Hosting

This project includes two options for handling production hosting, including reverse-proxying Django and handling SSL:

1. Use Caddy
2. Use Cloudflare Tunnel

You'll only need one of these! Which ever option you choose below, delete the other commented-out service in docker-compose.prod.yml.

Option 1: Use Caddy

Follow these steps:

1. Uncomment the caddy service in docker-compose.prod.yml
2. Uncomment all volumes in docker-compose.prod.yml
3. Uncomment the static_files_volume:... entry in django service's volumes property in docker-compose.prod.yml
4. Configure your server's firewall to expose TCP for ports 80 and 443, and UDP for port 443. These will allow Caddy to host the site, and generate and periodically update SSL certificates for the site via Let's Encrypt.

When these steps are complete, running start-prod.sh should make Django available on the public internet at https://$PROD_HOST_NAME.

Option 2: Use Cloudflare Tunnel

Uncomment the cloudflaretunnel service in docker-compose.prod.yml and then follow these steps:

1. Log into the Cloudflare Zero Trust dashboard
2. Click Access > Tunnels
3. Click Create a tunnel
4. Specify a Tunnel name
5. Click Docker on the Install connector step
6. Save the value of the --token flag in the page's docker command to this project's .env file as the CLOUDFLARE_TUNNEL_TOKEN environment variable
7. Run start-prod.sh to start the tunnel and display an entry under Connectors
8. Click Next
9. Set up a Public hostname
10. For the Service select "HTTP" and then enter "django:8000"
11. Click Save <tunnel name> tunnel to complete setup
12. Set the PROD_HOST_NAME variable in the .env file to the tunnel's configured Public hostname

When these steps are complete, running start-prod.sh should make Django available on the public internet at https://$PROD_HOST_NAME. No firewall ports need to be opened on the production host, and in fact you may wish to set up the firewall to block all incoming traffic for good measure.

Troubleshooting

The Django container reports "exited with code 3"

You probably forgot to replace the string "appname" with the actual name you passed to django-admin startproject. Check _app/gunicorn_appname.log to see if Gunicorn is erroring out with something like this:

ModuleNotFoundError: No module named 'appname'