Code-Memo

Using Docker with Django

1. Installing Docker and Docker Compose

On Ubuntu/Rocky Linux:

sudo apt update && sudo apt install -y docker.io docker-compose  # Ubuntu  
sudo yum install -y docker docker-compose  # Rocky Linux

Start and enable Docker:

sudo systemctl start docker  
sudo systemctl enable docker

Verify installation:

docker --version  
docker-compose --version

2. Creating a Dockerized Django Project

Inside the project root:

touch Dockerfile  
touch docker-compose.yml  
mkdir backend

3. Writing the Dockerfile

Create Dockerfile in the project root:

# Use official Python image
FROM python:3.11

# Set working directory
WORKDIR /app

# Copy requirements file and install dependencies
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy project files
COPY . .

# Set environment variables
ENV PYTHONUNBUFFERED=1

# Expose port
EXPOSE 8000

# Start the application
CMD ["gunicorn", "--bind", "0.0.0.0:8000", "backend.wsgi:application"]

4. Writing docker-compose.yml

Create docker-compose.yml in the project root:

version: '3.8'

services:
  web:
    build: .
    container_name: django_app
    ports:
      - "8000:8000"
    depends_on:
      - db
    volumes:
      - .:/app
    environment:
      - DJANGO_SECRET_KEY=supersecretkey
      - DJANGO_DEBUG=True
      - DATABASE_URL=postgres://user:password@db:5432/dbname

  db:
    image: postgres:15
    container_name: postgres_db
    restart: always
    environment:
      POSTGRES_DB: dbname
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - pg_data:/var/lib/postgresql/data

volumes:
  pg_data:

5. Configuring Django for Docker

Modify settings.py:

import os
import dj_database_url

SECRET_KEY = os.getenv("DJANGO_SECRET_KEY", "fallback-secret")
DEBUG = os.getenv("DJANGO_DEBUG", "False") == "True"

DATABASES = {
    "default": dj_database_url.config(default="sqlite:///db.sqlite3")
}

6. Running the Containers

Build and start the containers:

docker-compose up --build -d

Check running containers:

docker ps

View logs:

docker-compose logs -f web

Stop containers:

docker-compose down

Restart:

docker-compose up -d

7. Running Migrations and Creating a Superuser

Run migrations inside the container:

docker-compose exec web python manage.py migrate

Create a superuser:

docker-compose exec web python manage.py createsuperuser

8. Running Django in Development Mode

Modify docker-compose.yml for hot-reloading:

command: >
  sh -c "python manage.py runserver 0.0.0.0:8000"

Rebuild and restart:

docker-compose up --build -d

9. Deploying Django with Docker and Nginx

Modify docker-compose.yml:

version: '3.8'

services:
  web:
    build: .
    container_name: django_app
    expose:
      - "8000"
    depends_on:
      - db
    volumes:
      - .:/app
    environment:
      - DJANGO_SECRET_KEY=supersecretkey
      - DJANGO_DEBUG=False
      - DATABASE_URL=postgres://user:password@db:5432/dbname

  db:
    image: postgres:15
    container_name: postgres_db
    restart: always
    environment:
      POSTGRES_DB: dbname
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
    volumes:
      - pg_data:/var/lib/postgresql/data

  nginx:
    image: nginx:latest
    container_name: nginx_proxy
    ports:
      - "80:80"
    volumes:
      - ./nginx.conf:/etc/nginx/conf.d/default.conf
    depends_on:
      - web

volumes:
  pg_data:

Create nginx.conf:

server {
    listen 80;

    location / {
        proxy_pass http://web:8000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

Rebuild and restart:

docker-compose up --build -d

10. Running Gunicorn as a Background Service

Modify Dockerfile:

CMD ["gunicorn", "--workers=3", "--bind=0.0.0.0:8000", "backend.wsgi:application"]

Rebuild and restart:

docker-compose up --build -d

11. Monitoring Logs and Debugging

docker-compose logs -f web
docker-compose logs -f db
docker-compose logs -f nginx

Inspect running containers:

docker stats

12. Automating Deployment with GitHub Actions

Create .github/workflows/deploy.yml:

name: Deploy Django with Docker

on:
  push:
    branches:
      - main

jobs:
  deploy:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@v2

      - name: SSH into Server and Deploy
        uses: appleboy/ssh-action@master
        with:
          host: $
          username: $
          key: $
          script: |
            cd /home/ubuntu/django-docker
            git pull origin main
            docker-compose down
            docker-compose up --build -d

Add secrets in GitHub repository: