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)