Infra Docker

Docker Skill

Purpose

Containerization for development and deployment.

When Active

User mentions Docker, container, deployment.

Expertise

Dockerfile Patterns

• Multi-stage builds
• Layer optimization
• Caching strategies
• Security scanning

Docker Compose

• Service definition
• Volume management
• Network configuration
• Environment variables

Build Optimization

• Layer ordering
• .dockerignore
• BuildKit features
• Cache mounts

Production Patterns

• Minimal base images
• Non-root user
• Health checks
• Signal handling

Volume Management

• Named volumes
• Bind mounts
• Volume drivers
• Backup strategies

Network Configuration

• Bridge networks
• Overlay networks
• Service discovery
• Load balancing

Patterns

Multi-stage Node.js Build

FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

FROM node:20-alpine AS runner
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY package*.json ./
RUN npm ci --omit=dev
CMD ["node", "dist/index.js"]

Development Compose

version: '3.8'
services:
  app:
    build: .
    volumes:
      - .:/app
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=development
  db:
    image: postgres:15
    volumes:
      - postgres-data:/var/lib/postgresql/data
    environment:
      - POSTGRES_PASSWORD=secret

volumes:
  postgres-data:

Production Compose

version: '3.8'
services:
  app:
    image: registry.example.com/app:latest
    environment:
      - NODE_ENV=production
      - DATABASE_URL=${DATABASE_URL}
    restart: unless-stopped
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/health"]

.dockerignore

node_modules
npm-debug.log
.git
.env
*.md

Best Practices

• Use specific version tags
• Run as non-root user
• Minimize layers
• COPY before RUN for cache
• Use health checks
• Don't bundle development dependencies

Dependencies

• Docker Engine 20+
• Docker Compose v2