docker-workflows

name	docker-workflows
description	Create Dockerfiles, docker-compose configurations, and container workflows for Python projects with UV. Use when containerizing applications, setting up development environments, or deploying with Docker.

Docker Workflows Skill

When to Activate

Activate this skill when:

• Creating Dockerfiles for applications
• Setting up docker-compose environments
• Containerizing Python/UV projects
• Configuring multi-stage builds
• Managing container secrets

Quick Commands

# Build image
docker build -t my-app:latest .

# Run container
docker run -d -p 8000:8000 --name my-app my-app:latest

# View logs
docker logs -f my-app

# Execute in container
docker exec -it my-app bash

# Stop and remove
docker stop my-app && docker rm my-app

# Clean up
docker system prune -a

Basic Dockerfile (Python/UV)

FROM python:3.11-slim

WORKDIR /app

# Install UV
COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv

# Copy dependency files (layer caching)
COPY pyproject.toml uv.lock ./

# Install dependencies
RUN uv sync --frozen --no-dev

# Copy application
COPY . .

EXPOSE 8000

CMD ["uv", "run", "python", "main.py"]

Multi-Stage Build (Production)

# Stage 1: Builder
FROM python:3.11-slim AS builder

WORKDIR /app
COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv

COPY pyproject.toml uv.lock ./
RUN uv sync --frozen --no-dev

COPY . .

# Stage 2: Runtime
FROM python:3.11-slim

WORKDIR /app

# Create non-root user
RUN useradd -m -u 1000 appuser && chown appuser:appuser /app

# Copy from builder
COPY --from=builder /app/.venv /app/.venv
COPY --from=builder /app /app

USER appuser

ENV PATH="/app/.venv/bin:$PATH"

EXPOSE 8000
CMD ["python", "main.py"]

.dockerignore

__pycache__/
*.pyc
.git/
.env
.venv/
venv/
*.log
.DS_Store
.pytest_cache/
tests/
docs/
*.md

Docker Compose (App + Database)

version: '3.8'

services:
  app:
    build: .
    ports:
      - "8000:8000"
    environment:
      - DATABASE_URL=postgresql://user:password@db:5432/myapp
    depends_on:
      - db
    volumes:
      - ./app:/app  # Development: live reload

  db:
    image: postgres:15-alpine
    environment:
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=password
      - POSTGRES_DB=myapp
    volumes:
      - postgres_data:/var/lib/postgresql/data
    ports:
      - "5432:5432"

volumes:
  postgres_data:

Compose Commands

# Start all services
docker-compose up -d

# View logs
docker-compose logs -f app

# Stop services
docker-compose down

# Rebuild and restart
docker-compose up -d --build

# Run command in service
docker-compose exec app bash

# Remove volumes (deletes data!)
docker-compose down -v

Layer Caching Best Practice

# Good: Dependencies cached separately
COPY pyproject.toml uv.lock ./
RUN uv sync --frozen --no-dev
COPY . .

# Bad: Cache invalidated on every code change
COPY . .
RUN uv sync --frozen --no-dev

Security Essentials

# Use official slim images
FROM python:3.11-slim

# Run as non-root
RUN useradd -m -u 1000 appuser
USER appuser

# Don't include secrets in images
# Use runtime environment variables instead

Runtime Secrets

# Pass via environment
docker run -e API_KEY=secret my-app

# Use env file
docker run --env-file .env.production my-app

# With compose
services:
  app:
    env_file:
      - .env.production

Volume Types

# Named volume (data persistence)
docker run -v postgres_data:/var/lib/postgresql/data postgres

# Bind mount (development)
docker run -v $(pwd)/app:/app my-app

Debugging

# Interactive shell
docker exec -it container_name bash

# Real-time logs
docker logs -f --tail 100 container_name

# Inspect configuration
docker inspect container_name

# Resource usage
docker stats container_name

# Copy files
docker cp container_name:/app/logs ./logs

Common Issues

Container exits immediately

docker logs container_name  # Check for errors
docker run -it app:v1 bash  # Debug interactively

Can't connect to container

docker ps                           # Check port mapping
docker inspect container_name       # Check network config

Out of disk space

docker system df           # Check usage
docker system prune -a     # Clean everything

Related Resources

See AgentUsage/docker_guide.md for complete documentation including:

• Advanced multi-stage patterns
• Docker Compose variations
• Production optimization
• CI/CD integration