Docker Environment Initialization Skill

Overview

This skill creates a complete Docker environment for a project, including:

• Dockerfile optimized for the application type
• docker-compose.yaml with all required services
• .dockerignore for efficient builds
• .env.example for environment configuration

Activation

Use this skill when:

• Setting up Docker for a new project
• Migrating an existing project to Docker
• Adding Docker support to a codebase

Process

1. Detect Project Type

Analyze the project to determine:

• Primary language (Node.js, Python, PHP, Go, etc.)
• Framework (Laravel, Express, Django, etc.)
• Required services (database, cache, queue)
• Existing configuration files

2. Consult Documentation

Read relevant documentation:

• 02-dockerfile.md for Dockerfile patterns
• 03-compose-fundamentals.md for compose structure
• 05-databases.md if database needed
• 10-architecture.md for folder structure

3. Generate Files

Dockerfile

# Multi-stage build pattern
FROM base AS builder
# Build steps

FROM base AS production
# Production setup

Key elements:

• Use appropriate base image
• Multi-stage build for smaller images
• Non-root user for security
• Health check
• Proper COPY order for caching

docker-compose.yaml

services:
  app:
    build: .
    # Configuration

  db:
    image: postgres:16
    # Configuration

volumes:
  # Named volumes

networks:
  # Network configuration

Key elements:

• No version field (modern compose)
• Health checks
• Dependencies with conditions
• Named volumes
• Proper networking

.dockerignore

node_modules/
.git/
.env
*.log

.env.example

# Application
NODE_ENV=development
PORT=3000

# Database
DB_HOST=db
DB_USER=appuser
DB_PASSWORD=

4. Provide Instructions

Include:

• How to start services
• Available commands
• Environment setup
• Development workflow

Templates by Project Type

Node.js

FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
USER node
EXPOSE 3000
CMD ["node", "src/index.js"]

Python

FROM python:3.12-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
USER nobody
EXPOSE 8000
CMD ["python", "app.py"]

PHP/Laravel

FROM php:8.3-fpm-alpine
WORKDIR /var/www/html
RUN apk add --no-cache postgresql-dev && \
    docker-php-ext-install pdo pdo_pgsql
COPY --from=composer:latest /usr/bin/composer /usr/bin/composer
COPY . .
RUN composer install --no-dev --optimize-autoloader
EXPOSE 9000
CMD ["php-fpm"]

Go

FROM golang:1.22-alpine AS builder
WORKDIR /app
COPY go.* ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 go build -o main .

FROM alpine:latest
COPY --from=builder /app/main .
EXPOSE 8080
CMD ["./main"]

Output

Generated files:

• Dockerfile
• docker-compose.yaml (or compose.yaml)
• .dockerignore
• .env.example
• docker/ folder for additional configs (if needed)