Docker + Python: The Complete Production Setup Guide

#devops #docker #python #tutorial

Docker + Python: The Complete Production Setup Guide

Here's how to containerize Python apps properly for production.

Multi-Stage Dockerfile

# Build stage
FROM python:3.12-slim AS builder

WORKDIR /app

# Install build dependencies
RUN apt-get update && apt-get install -y --no-install-recommends \
    build-essential \
    && rm -rf /var/lib/apt/lists/*

# Install Python dependencies
COPY requirements.txt .
RUN pip install --no-cache-dir --user -r requirements.txt

# Production stage
FROM python:3.12-slim AS production

WORKDIR /app

# Copy installed packages from builder
COPY --from=builder /root/.local /root/.local

# Create non-root user
RUN useradd --create-home --shell /bin/bash appuser
USER appuser

# Copy application code
COPY --chown=appuser:appuser . .

# Environment
ENV PATH=/root/.local/bin:$PATH
ENV PYTHONUNBUFFERED=1
ENV PYTHONDONTWRITEBYTECODE=1

EXPOSE 8000

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
    CMD curl -f http://localhost:8000/health || exit 1

CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000", "--workers", "4"]

docker-compose.yml

version: '3.8'

services:
  api:
    build:
      context: .
      target: production
    ports:
      - "8000:8000"
    environment:
      - DATABASE_URL=postgresql://user:pass@db:5432/mydb
      - SECRET_KEY=${SECRET_KEY}
    depends_on:
      db:
        condition: service_healthy
    restart: unless-stopped

  db:
    image: postgres:16-alpine
    volumes:
      - postgres_data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
      POSTGRES_DB: mydb
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U user -d mydb"]
      interval: 10s
      timeout: 5s
      retries: 5

  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf
      - ./certbot:/etc/letsencrypt
    depends_on:
      - api

volumes:
  postgres_data:

.dockerignore

.git
.gitignore
__pycache__
*.pyc
*.pyo
*.pyd
.Python
env/
venv/
.env
.pytest_cache
.coverage
htmlcov/
dist/
*.egg-info/

Useful Commands

# Build and run
docker compose up -d --build

# View logs
docker compose logs -f api

# Scale workers
docker compose up -d --scale api=3

# Access container
docker compose exec api bash

# Clean up
docker compose down -v