Containerization Assistant

What it does

When your agent uses it

• Creating Dockerfiles for Node.js
• Other applications
• Setting up multi-service environments with Docker Compose
• Generating Kubernetes deployments

Example prompts

• “/containerization-assistant”

Requirements

• Python 3
• Node.js
• Docker

Workflow steps

5 steps, taken from the step headings in SKILL.md.

1. 1Analyze Project
2. 2Choose Approach
3. 3Customize Configuration
4. 4Build and Test
5. 5Optimize and Deploy

What it can do on your machine

Read from SKILL.md and the folder at commit 4f38503. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships script files (Go and Java), which the agent can run.

  Shell commands in SKILL.md call:

  • docker
  • docker-compose
  • kubectl
  • aws

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md. Its commands use docker, kubectl and aws, which can reach the network depending on how they are called.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names these keys or tokens, usually read from environment variables:

  • DOCKER_PASSWORD

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Containerization Assistant loads about 2.9k tokens when it runs, and up to ~6.6k if it reads all its reference files. Until then it costs about 142 tokens; SKILL.md has 658 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~142

When it runs · the whole SKILL.md, loaded when a task matches

~2.9k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~6.6k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NoteMentions a .env fileSKILL.md:36

  cp assets/.env.example ./.env

• NoteMentions a .env fileSKILL.md:38

  # Edit .env with your configuration

• NoteMentions a .env fileSKILL.md:186

  - `.env` - Configuration variables

• NoteMentions a .env fileSKILL.md:203

  - `.env` - Database and Celery configuration

• NoteMentions a .env fileSKILL.md:238

  .env

• NoteMentions a .env fileSKILL.md:368

  **Development** (`.env`):

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from ArabelaTso/Skills-4-SE at commit 4f38503, republished under its Apache-2.0 licence (© ArabelaTso). 658 words, ~2,902 tokens.

name

containerization-assistant

description

Generate Dockerfiles, Docker Compose configurations, and Kubernetes manifests for containerizing applications. Use when: (1) Creating Dockerfiles for Node.js, Python, Java, Go, or other applications, (2) Setting up multi-service environments with Docker Compose, (3) Generating Kubernetes deployments, services, and ingress configurations, (4) Optimizing container images for production, (5) Implementing containerization best practices. Provides both ready-to-use templates and custom-generated configurations based on project requirements.

# Node.js application
cp assets/Dockerfile.nodejs ./Dockerfile

# Python application
cp assets/Dockerfile.python ./Dockerfile

# Java application (Spring Boot)
cp assets/Dockerfile.java ./Dockerfile

# Go application
cp assets/Dockerfile.go ./Dockerfile

# Multi-service application template
cp assets/docker-compose.yml ./
cp assets/.env.example ./.env

# Edit .env with your configuration

# Update base image version
FROM node:18-alpine  # Change version as needed

# Add build arguments
ARG NODE_ENV=production

# Modify exposed port
EXPOSE 3000  # Change to your port

# Update startup command
CMD ["node", "server.js"]  # Change to your entry point

services:
  web:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "3000:3000"  # Change port mapping
    environment:
      - DATABASE_URL=${DATABASE_URL}  # Add environment variables

# Build Docker image
docker build -t myapp:1.0.0 .

# Test locally
docker run -p 3000:3000 myapp:1.0.0

# Test with Docker Compose
docker-compose up -d

# View logs
docker-compose logs -f

# Stop services
docker-compose down

services/
  api/
    Dockerfile
  auth/
    Dockerfile
  worker/
    Dockerfile
docker-compose.yml
.env

# Build stage
FROM node:18-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

# Production stage
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"]

# Use non-root user
RUN addgroup -g 1001 -S nodejs && \
    adduser -S nodejs -u 1001 -G nodejs
USER nodejs

# Use specific versions
FROM node:18.17.0-alpine  # Not 'latest'

# Scan for vulnerabilities
# docker scan myapp:latest

# Order layers from least to most frequently changing
COPY package*.json ./  # Changes less often
RUN npm ci
COPY . .  # Changes more often

# Use .dockerignore
# node_modules
# .git
# *.md

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    spec:
      containers:
      - name: myapp
        image: myapp:1.0.0
        resources:
          requests:
            memory: "256Mi"
            cpu: "250m"
          limits:
            memory: "512Mi"
            cpu: "500m"

apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  type: ClusterIP
  selector:
    app: myapp
  ports:
  - port: 80
    targetPort: 8080
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
  annotations:
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
spec:
  tls:
  - hosts:
    - myapp.example.com
    secretName: myapp-tls
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp-service
            port:
              number: 80

NODE_ENV=development
DATABASE_URL=postgresql://localhost/myapp_dev
DEBUG=true

apiVersion: v1
kind: Secret
metadata:
  name: myapp-secrets
type: Opaque
stringData:
  database_url: "postgresql://prod-db/myapp"
  api_key: "secret-key"

apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
data:
  log_level: "info"
  feature_flags: |
    {
      "new_ui": true,
      "beta_features": false
    }

RUN chown -R appuser:appuser /app
USER appuser

kubectl describe pod <pod-name>
# Check events for resource constraints or image pull issues

resources:
  limits:
    memory: "512Mi"  # Increase memory limit

name: Build and Push Docker Image

on:
  push:
    branches: [main]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - name: Build Docker image
        run: docker build -t myapp:${{ github.sha }} .

      - name: Push to registry
        run: |
          echo ${{ secrets.DOCKER_PASSWORD }} | docker login -u ${{ secrets.DOCKER_USERNAME }} --password-stdin
          docker push myapp:${{ github.sha }}

docker tag myapp:1.0.0 username/myapp:1.0.0
docker push username/myapp:1.0.0

aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin 123456789.dkr.ecr.us-east-1.amazonaws.com
docker tag myapp:1.0.0 123456789.dkr.ecr.us-east-1.amazonaws.com/myapp:1.0.0
docker push 123456789.dkr.ecr.us-east-1.amazonaws.com/myapp:1.0.0

© ArabelaTso, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 8 other files (references, assets) in skills/containerization-assistant of ArabelaTso/Skills-4-SE.

• SKILL.md
• assets/.env.example
• assets/Dockerfile.go
• assets/Dockerfile.java
• assets/Dockerfile.nodejs
• assets/Dockerfile.python
• assets/docker-compose.yml
• references/dockerfile_best_practices.md
• references/kubernetes_patterns.md

Open the folder on GitHubat commit 4f38503