Python Devops

Python DevOps Patterns

Optimized Dockerfile

# Build stage
FROM python:3.11-slim AS builder
WORKDIR /build

# Install uv (fast package manager)
COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /bin/

# Copy dependency specs first (cache layer)
COPY pyproject.toml uv.lock ./
RUN uv sync --frozen --no-dev --no-editable

# Runtime stage
FROM python:3.11-slim
WORKDIR /app

# Non-root user
RUN groupadd -r appgroup && useradd -r -g appgroup appuser

# Copy only the installed packages
COPY --from=builder /build/.venv /app/.venv
ENV PATH="/app/.venv/bin:$PATH"

COPY --chown=appuser:appgroup . .

USER appuser

# Health check
HEALTHCHECK --interval=30s --timeout=10s --retries=3 \
    CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/health')"

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

GitHub Actions CI

name: Python CI

on:
  push:
    branches: [main]
  pull_request:

jobs:
  test:
    runs-on: ubuntu-latest
    services:
      postgres:
        image: postgres:16
        env:
          POSTGRES_USER: test
          POSTGRES_PASSWORD: test
          POSTGRES_DB: test
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
    
    steps:
      - uses: actions/checkout@v4
      
      - name: Install uv
        uses: astral-sh/setup-uv@v3
      
      - name: Set up Python
        run: uv python install 3.11
      
      - name: Install dependencies
        run: uv sync --frozen
      
      - name: Run ruff
        run: uv run ruff check .
      
      - name: Run mypy
        run: uv run mypy app
      
      - name: Run tests
        env:
          DATABASE_URL: postgresql+asyncpg://test:test@localhost/test
        run: uv run pytest --cov=app --cov-fail-under=80

Health Check Endpoint

from fastapi import APIRouter
from sqlalchemy import text

router = APIRouter()

@router.get("/health")
async def health_check(db: AsyncSession = Depends(get_db)) -> dict:
    try:
        await db.execute(text("SELECT 1"))
        db_status = "ok"
    except Exception:
        db_status = "error"
    
    return {
        "status": "ok" if db_status == "ok" else "degraded",
        "database": db_status,
        "version": settings.app_version,
    }