Docker Helper Skill

Docker Helper 技能

Docker Compose generation, optimization, and troubleshooting assistance.

Docker Compose生成、优化及故障排查辅助支持。

Instructions

说明

You are a Docker and containerization expert. When invoked:

Generate Docker Files:
- Create Dockerfile based on project type
- Generate docker-compose.yml for multi-service apps
- Optimize for build time and image size
- Follow best practices for security and performance
Optimize Existing Configurations:
- Reduce image sizes (multi-stage builds)
- Improve layer caching
- Security hardening
- Resource limits and health checks
Troubleshoot Issues:
- Container startup failures
- Network connectivity problems
- Volume mounting issues
- Performance problems
Provide Best Practices:
- Image naming and tagging
- Secrets management
- Logging configuration
- Development vs production configs

你是一名Docker和容器化专家。被调用时：

生成Docker文件:
- 根据项目类型创建Dockerfile
- 为多服务应用生成docker-compose.yml
- 针对构建时间和镜像大小进行优化
- 遵循安全与性能最佳实践
优化现有配置:
- 减小镜像大小（多阶段构建）
- 改进分层缓存
- 安全加固
- 资源限制与健康检查
排查问题:
- 容器启动失败
- 网络连接问题
- 卷挂载问题
- 性能问题
提供最佳实践:
- 镜像命名与打标签
- 密钥管理
- 日志配置
- 开发与生产环境配置差异

Dockerfile Best Practices

Dockerfile 最佳实践

Node.js Application

Node.js 应用

dockerfile

undefined

dockerfile

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Multi-stage build for smaller image

FROM node:18-alpine AS builder

WORKDIR /app

FROM node:18-alpine AS builder

WORKDIR /app

Copy package files first (better layer caching)

COPY package*.json ./ RUN npm ci --only=production

Copy application code

COPY . . RUN npm run build

Production stage

FROM node:18-alpine

WORKDIR /app

FROM node:18-alpine

WORKDIR /app

Run as non-root user

RUN addgroup -g 1001 -S nodejs &&
adduser -S nodejs -u 1001

Copy only necessary files from builder

COPY --from=builder --chown=nodejs:nodejs /app/dist ./dist COPY --from=builder --chown=nodejs:nodejs /app/node_modules ./node_modules COPY --chown=nodejs:nodejs package*.json ./

USER nodejs

EXPOSE 3000

COPY --from=builder --chown=nodejs:nodejs /app/dist ./dist COPY --from=builder --chown=nodejs:nodejs /app/node_modules ./node_modules COPY --chown=nodejs:nodejs package*.json ./

USER nodejs

EXPOSE 3000

Use exec form for proper signal handling

CMD ["node", "dist/index.js"]

Health check

HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3
CMD node healthcheck.js

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HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3
CMD node healthcheck.js

undefined

Python Application

Python 应用

dockerfile

FROM python:3.11-slim

WORKDIR /app

dockerfile

FROM python:3.11-slim

WORKDIR /app

Install dependencies in separate layer

COPY requirements.txt . RUN pip install --no-cache-dir -r requirements.txt

Copy application

COPY . .

Create non-root user

RUN useradd -m -u 1001 appuser &&
chown -R appuser:appuser /app

USER appuser

EXPOSE 8000

CMD ["python", "app.py"]

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RUN useradd -m -u 1001 appuser &&
chown -R appuser:appuser /app

USER appuser

EXPOSE 8000

CMD ["python", "app.py"]

undefined

Go Application

Go 应用

dockerfile

undefined

dockerfile

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Build stage

FROM golang:1.21-alpine AS builder

WORKDIR /app

COPY go.mod go.sum ./ RUN go mod download

COPY . . RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .

FROM golang:1.21-alpine AS builder

WORKDIR /app

COPY go.mod go.sum ./ RUN go mod download

COPY . . RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .

Final stage - minimal image

FROM alpine:latest

RUN apk --no-cache add ca-certificates

WORKDIR /root/

COPY --from=builder /app/main .

EXPOSE 8080

CMD ["./main"]

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FROM alpine:latest

RUN apk --no-cache add ca-certificates

WORKDIR /root/

COPY --from=builder /app/main .

EXPOSE 8080

CMD ["./main"]

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Docker Compose Examples

Docker Compose 示例

Full Stack Application

全栈应用

yaml

version: '3.8'

services:
  # Frontend
  web:
    build:
      context: ./web
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
      - API_URL=http://api:8000
    depends_on:
      api:
        condition: service_healthy
    networks:
      - frontend
    restart: unless-stopped

  # Backend API
  api:
    build:
      context: ./api
      dockerfile: Dockerfile
    ports:
      - "8000:8000"
    environment:
      - DATABASE_URL=postgresql://user:password@db:5432/myapp
      - REDIS_URL=redis://cache:6379
    env_file:
      - .env
    depends_on:
      db:
        condition: service_healthy
      cache:
        condition: service_started
    networks:
      - frontend
      - backend
    volumes:
      - ./logs:/app/logs
    restart: unless-stopped
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8000/health"]
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 40s

  # Database
  db:
    image: postgres:15-alpine
    environment:
      - POSTGRES_DB=myapp
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=password
    volumes:
      - postgres_data:/var/lib/postgresql/data
      - ./init.sql:/docker-entrypoint-initdb.d/init.sql:ro
    networks:
      - backend
    restart: unless-stopped
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U user -d myapp"]
      interval: 10s
      timeout: 5s
      retries: 5

  # Redis Cache
  cache:
    image: redis:7-alpine
    command: redis-server --appendonly yes
    volumes:
      - redis_data:/data
    networks:
      - backend
    restart: unless-stopped

  # Nginx Reverse Proxy
  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf:ro
      - ./ssl:/etc/nginx/ssl:ro
    depends_on:
      - web
      - api
    networks:
      - frontend
    restart: unless-stopped

networks:
  frontend:
    driver: bridge
  backend:
    driver: bridge

volumes:
  postgres_data:
  redis_data:

yaml

version: '3.8'

services:
  # Frontend
  web:
    build:
      context: ./web
      dockerfile: Dockerfile
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
      - API_URL=http://api:8000
    depends_on:
      api:
        condition: service_healthy
    networks:
      - frontend
    restart: unless-stopped

  # Backend API
  api:
    build:
      context: ./api
      dockerfile: Dockerfile
    ports:
      - "8000:8000"
    environment:
      - DATABASE_URL=postgresql://user:password@db:5432/myapp
      - REDIS_URL=redis://cache:6379
    env_file:
      - .env
    depends_on:
      db:
        condition: service_healthy
      cache:
        condition: service_started
    networks:
      - frontend
      - backend
    volumes:
      - ./logs:/app/logs
    restart: unless-stopped
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8000/health"]
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 40s

  # Database
  db:
    image: postgres:15-alpine
    environment:
      - POSTGRES_DB=myapp
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=password
    volumes:
      - postgres_data:/var/lib/postgresql/data
      - ./init.sql:/docker-entrypoint-initdb.d/init.sql:ro
    networks:
      - backend
    restart: unless-stopped
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U user -d myapp"]
      interval: 10s
      timeout: 5s
      retries: 5

  # Redis Cache
  cache:
    image: redis:7-alpine
    command: redis-server --appendonly yes
    volumes:
      - redis_data:/data
    networks:
      - backend
    restart: unless-stopped

  # Nginx Reverse Proxy
  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf:ro
      - ./ssl:/etc/nginx/ssl:ro
    depends_on:
      - web
      - api
    networks:
      - frontend
    restart: unless-stopped

networks:
  frontend:
    driver: bridge
  backend:
    driver: bridge

volumes:
  postgres_data:
  redis_data:

Development Environment

开发环境

yaml

version: '3.8'

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile.dev
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=development
    volumes:
      - .:/app
      - /app/node_modules  # Anonymous volume for node_modules
    command: npm run dev
    networks:
      - dev_network

  db:
    image: postgres:15-alpine
    environment:
      - POSTGRES_DB=dev_db
      - POSTGRES_USER=dev
      - POSTGRES_PASSWORD=dev_password
    ports:
      - "5432:5432"
    volumes:
      - dev_db_data:/var/lib/postgresql/data
    networks:
      - dev_network

volumes:
  dev_db_data:

networks:
  dev_network:

yaml

version: '3.8'

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile.dev
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=development
    volumes:
      - .:/app
      - /app/node_modules  # Anonymous volume for node_modules
    command: npm run dev
    networks:
      - dev_network

  db:
    image: postgres:15-alpine
    environment:
      - POSTGRES_DB=dev_db
      - POSTGRES_USER=dev
      - POSTGRES_PASSWORD=dev_password
    ports:
      - "5432:5432"
    volumes:
      - dev_db_data:/var/lib/postgresql/data
    networks:
      - dev_network

volumes:
  dev_db_data:

networks:
  dev_network:

Usage Examples

使用示例

@docker-helper
@docker-helper --generate-dockerfile
@docker-helper --optimize
@docker-helper --compose
@docker-helper --troubleshoot

@docker-helper
@docker-helper --generate-dockerfile
@docker-helper --optimize
@docker-helper --compose
@docker-helper --troubleshoot

Optimization Techniques

优化技巧

Multi-Stage Builds

多阶段构建

dockerfile

undefined

dockerfile

undefined

Reduces final image size by 70-90%

FROM node:18 AS builder WORKDIR /app COPY package*.json ./ RUN npm ci COPY . . RUN npm run build

FROM node:18-alpine WORKDIR /app COPY --from=builder /app/dist ./dist COPY --from=builder /app/node_modules ./node_modules CMD ["node", "dist/index.js"]

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FROM node:18 AS builder WORKDIR /app COPY package*.json ./ RUN npm ci COPY . . RUN npm run build

FROM node:18-alpine WORKDIR /app COPY --from=builder /app/dist ./dist COPY --from=builder /app/node_modules ./node_modules CMD ["node", "dist/index.js"]

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Layer Caching

分层缓存

dockerfile

undefined

dockerfile

undefined

❌ Bad - Invalidates cache on any file change

COPY . . RUN npm install

✓ Good - Cache dependencies separately

COPY package*.json ./ RUN npm install COPY . .

undefined

COPY package*.json ./ RUN npm install COPY . .

undefined

Reduce Image Size

减小镜像大小

dockerfile

undefined

dockerfile

undefined

Use alpine variants (much smaller)

FROM node:18-alpine # ~170MB vs ~900MB for node:18

Clean up in same layer

RUN apt-get update &&
apt-get install -y package &&
apt-get clean &&
rm -rf /var/lib/apt/lists/*

Use .dockerignore

Create .dockerignore file:

node_modules

.git

*.md

.env*

undefined

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Security Best Practices

安全最佳实践

dockerfile

undefined

dockerfile

undefined

Don't run as root

RUN adduser -D -u 1001 appuser USER appuser

Scan for vulnerabilities

Use: docker scan myimage:tag

Use specific tags, not 'latest'

FROM node:18.16.0-alpine # Not: FROM node:latest

Don't store secrets in image

Use environment variables or secrets management

Minimize attack surface

Use minimal base images (alpine, distroless)

Keep base images updated

Regularly rebuild and update

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Common Issues & Solutions

常见问题与解决方案

Issue: Container Exits Immediately

问题：容器立即退出

bash

undefined

bash

undefined

Check logs

docker logs <container_id>

Run interactively to debug

docker run -it <image> /bin/sh

Check entrypoint/command

docker inspect <container_id> | grep -A5 Cmd

undefined

docker inspect <container_id> | grep -A5 Cmd

undefined

Issue: Cannot Connect to Service

问题：无法连接到服务

yaml

undefined

yaml

undefined

Ensure services are on same network

networks:

mynetwork

networks:

mynetwork

Use service name as hostname

DATABASE_URL=postgresql://db:5432/myapp # 'db' is service name

Check if service is ready

depends_on: db: condition: service_healthy

undefined

depends_on: db: condition: service_healthy

undefined

Issue: Volume Permission Problems

问题：卷权限问题

dockerfile

undefined

dockerfile

undefined

Match host user ID

RUN adduser -u 1001 appuser USER appuser

Or change ownership in entrypoint

ENTRYPOINT ["sh", "-c", "chown -R appuser:appuser /data && exec "$@""]

undefined

ENTRYPOINT ["sh", "-c", "chown -R appuser:appuser /data && exec "$@""]

undefined

Issue: Slow Builds

问题：构建速度慢

dockerfile

undefined

dockerfile

undefined

Use build cache effectively

COPY package*.json ./ RUN npm ci COPY . .

Use BuildKit

Set: DOCKER_BUILDKIT=1

Use .dockerignore

Exclude: node_modules, .git, build artifacts

undefined

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Docker Commands Reference

Docker 命令参考

bash

undefined

bash

undefined

Build image

docker build -t myapp:latest .

Run container

docker run -d -p 3000:3000 --name myapp myapp:latest

View logs

docker logs -f myapp

Execute command in container

docker exec -it myapp /bin/sh

Stop and remove

docker stop myapp && docker rm myapp

Compose commands

docker-compose up -d docker-compose down docker-compose logs -f docker-compose ps

Clean up

docker system prune -a docker volume prune

undefined

docker system prune -a docker volume prune

undefined

Health Checks

健康检查

dockerfile

undefined

dockerfile

undefined

Node.js

HEALTHCHECK --interval=30s --timeout=3s
CMD node healthcheck.js || exit 1

Python

HEALTHCHECK --interval=30s --timeout=3s
CMD python -c "import requests; requests.get('http://localhost:8000/health')" || exit 1

Simple HTTP check

HEALTHCHECK --interval=30s --timeout=3s
CMD wget --no-verbose --tries=1 --spider http://localhost:8000/health || exit 1

undefined

HEALTHCHECK --interval=30s --timeout=3s
CMD wget --no-verbose --tries=1 --spider http://localhost:8000/health || exit 1

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Notes

注意事项

Always use specific version tags, not
```
latest
```
Implement health checks for critical services
Use multi-stage builds to reduce image size
Never store secrets in Dockerfiles or images
Use
```
.dockerignore
```
to exclude unnecessary files
Run containers as non-root users
Implement proper logging (stdout/stderr)
Use volumes for persistent data
Configure resource limits in production
Regularly update base images for security patches

始终使用特定版本标签，而非
```
latest
```
为关键服务实现健康检查
使用多阶段构建减小镜像大小
切勿在Dockerfile或镜像中存储密钥
使用
```
.dockerignore
```
排除不必要的文件
以非root用户运行容器
实现适当的日志记录（stdout/stderr）
使用卷存储持久化数据
在生产环境中配置资源限制
定期更新基础镜像以获取安全补丁

docker-helper

Original

Translation

Docker Helper Skill

Docker Helper 技能

Instructions

说明

Dockerfile Best Practices

Dockerfile 最佳实践

Node.js Application

Node.js 应用

Multi-stage build for smaller image

Multi-stage build for smaller image

Copy package files first (better layer caching)

Copy package files first (better layer caching)

Copy application code

Copy application code

Production stage

Production stage

Run as non-root user

Run as non-root user

Copy only necessary files from builder

Copy only necessary files from builder

Use exec form for proper signal handling

Use exec form for proper signal handling

Health check

Health check

Python Application

Python 应用

Install dependencies in separate layer

Install dependencies in separate layer

Copy application

Copy application

Create non-root user

Create non-root user

Go Application

Go 应用

Build stage

Build stage

Final stage - minimal image

Final stage - minimal image

Docker Compose Examples

Docker Compose 示例

Full Stack Application

全栈应用

Development Environment

开发环境

Usage Examples

使用示例

Optimization Techniques

优化技巧

Multi-Stage Builds

多阶段构建

Reduces final image size by 70-90%

Reduces final image size by 70-90%

Layer Caching

分层缓存

❌ Bad - Invalidates cache on any file change

❌ Bad - Invalidates cache on any file change

✓ Good - Cache dependencies separately

✓ Good - Cache dependencies separately

Reduce Image Size

减小镜像大小

Use alpine variants (much smaller)

Use alpine variants (much smaller)

Clean up in same layer

Clean up in same layer

Use .dockerignore

Use .dockerignore

Create .dockerignore file:

Create .dockerignore file:

node_modules

node_modules

.git

.git

*.md

*.md

.env*

.env*

Security Best Practices