Docker Wizard

Docker Wizard

Generate production-ready Dockerfiles and docker-compose.yml files by analyzing your project. Follows best practices, optimizes image size, and includes security hardening.

What This Skill Does

• Auto-detects project type and dependencies
• Generates multi-stage builds for smaller images
• Applies security best practices (non-root user, minimal base images)
• Creates docker-compose.yml for multi-service setups
• Includes development and production configurations
• Optimizes layer caching for faster builds

Instructions

Phase 1: Project Analysis

1. Detect project type:

   Use Glob to find:
   - package.json → Node.js
   - requirements.txt/pyproject.toml → Python
   - go.mod → Go
   - Cargo.toml → Rust
   - pom.xml/build.gradle → Java
   

2. Analyze dependencies:

   Use Read to examine:
   - Runtime dependencies
   - Build dependencies
   - Environment requirements
   - Port requirements
   

Phase 2: Dockerfile Generation

Generate optimized multi-stage Dockerfile:

# Example for Node.js

# Stage 1: Dependencies
FROM node:20-alpine AS deps
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production

# Stage 2: Build
FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

# Stage 3: Production
FROM node:20-alpine AS runner
WORKDIR /app

# Security: Run as non-root user
RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 nextjs

COPY --from=deps --chown=nextjs:nodejs /app/node_modules ./node_modules
COPY --from=builder --chown=nextjs:nodejs /app/dist ./dist

USER nextjs
EXPOSE 3000
CMD ["node", "dist/index.js"]

Best practices applied:

• Multi-stage builds (reduce image size by 70%)
• Alpine base images (minimal attack surface)
• Non-root user (security)
• Optimized layer caching
• .dockerignore generation

Phase 3: Docker Compose Generation

Create docker-compose.yml for multi-service setups:

version: '3.9'

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
      - DATABASE_URL=postgresql://user:pass@db:5432/myapp
    depends_on:
      db:
        condition: service_healthy
    restart: unless-stopped

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

  redis:
    image: redis:7-alpine
    ports:
      - "6379:6379"
    restart: unless-stopped

volumes:
  postgres_data:

Phase 4: Additional Files

1. .dockerignore:

   node_modules
   npm-debug.log
   .git
   .env
   *.md
   .vscode
   .idea
   coverage
   .DS_Store
   

2. docker-compose.dev.yml (development overrides):

   version: '3.9'
   
   services:
     app:
       build:
         target: builder
       volumes:
         - .:/app
         - /app/node_modules
       environment:
         - NODE_ENV=development
       command: npm run dev
   

Language-Specific Optimizations

Node.js

# Use npm ci for faster, reproducible builds
RUN npm ci --only=production

# Leverage layer caching
COPY package*.json ./
RUN npm ci
COPY . .

Python

# Use pip with cache mount
RUN --mount=type=cache,target=/root/.cache/pip \
    pip install -r requirements.txt

# Use multi-stage for smaller images
FROM python:3.11-slim
COPY --from=builder /usr/local/lib/python3.11/site-packages /usr/local/lib/python3.11/site-packages

Go

# Multi-stage with scratch base
FROM golang:1.21-alpine AS builder
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app .

FROM scratch
COPY --from=builder /app/app /app
CMD ["/app"]

Security Best Practices

1. Non-root user: Always run as non-root
2. Minimal base: Use Alpine or distroless
3. No secrets: Never COPY .env files
4. Health checks: Include HEALTHCHECK directive
5. Read-only rootfs: Add security-opt in compose

Tool Requirements

• Read: Examine project files
• Write: Create Dockerfiles and compose files
• Glob: Find project structure
• Grep: Search for patterns
• Bash: Test docker build (optional)

Examples

Example 1: Full Stack App

User: "Generate Docker setup for my MERN app"

Generated:

• Multi-stage Dockerfile for React frontend
• Dockerfile for Node.js backend
• docker-compose.yml with MongoDB, Redis
• Nginx reverse proxy config
• .dockerignore for both services

Example 2: Microservices

User: "Create Docker Compose for microservices"

Generated:

• Service-specific Dockerfiles
• Shared docker-compose with networking
• Environment-specific overrides
• Health checks and dependencies

Best Practices

• Use specific versions, not latest tags
• Implement health checks for all services
• Use bind mounts in development, volumes in production
• Set resource limits (memory, CPU)
• Enable logging drivers

Related Skills

• k8s-generator - Generate Kubernetes manifests
• cicd-pipeline-builder - Build CI/CD pipelines

Changelog

Version 1.0.0

• Initial release
• Multi-stage build support
• Docker Compose generation
• Security hardening
• Multiple language support

Author

GLINCKER Team

• Repository: claude-code-marketplace