# Writing Dockerfiles

Writing optimized, secure, multi-stage Dockerfiles with language-specific patterns...

- Repository: https://github.com/ancoleman/ai-design-components (526 stars)
- Category: Writing
- License: MIT
- Last updated: 2025-12-11
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add ancoleman/ai-design-components --skill writing-dockerfiles -g -a claude-code -y`
Codex: `npx skills add ancoleman/ai-design-components --skill writing-dockerfiles -g -a codex -y`
Cursor: `npx skills add ancoleman/ai-design-components --skill writing-dockerfiles -g -a cursor -y`
Gemini CLI: `npx skills add ancoleman/ai-design-components --skill writing-dockerfiles -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add ancoleman/ai-design-components`

## Description

Writing optimized, secure, multi-stage Dockerfiles with language-specific patterns (Python, Node.js, Go, Rust), BuildKit features, and distroless images. Use when containerizing applications, optimizing existing Dockerfiles, or reducing image sizes.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Writing Dockerfiles

Create production-grade Dockerfiles with multi-stage builds, security hardening, and language-specific optimizations.

## When to Use This Skill

Invoke when:
- "Write a Dockerfile for [Python/Node.js/Go/Rust] application"
- "Optimize this Dockerfile to reduce image size"
- "Use multi-stage build for..."
- "Secure Dockerfile with non-root user"
- "Use distroless base image"
- "Add BuildKit cache mounts"
- "Prevent secrets from leaking in Docker layers"

## Quick Decision Framework

Ask three questions to determine the approach:

**1. What language?**
- Python → See `references/python-dockerfiles.md`
- Node.js → See `references/nodejs-dockerfiles.md`
- Go → See `references/go-dockerfiles.md`
- Rust → See `references/rust-dockerfiles.md`
- Java → See `references/java-dockerfiles.md`

**2. Is security critical?**
- YES → Use distroless runtime images (see `references/security-hardening.md`)
- NO → Use slim/alpine base images

**3. Is image size critical?**
- YES (<50MB) → Multi-stage + distroless + static linking
- NO (<500MB) → Multi-stage + slim base images

## Core Concepts

### Multi-Stage Builds

Separate build environment from runtime environment to minimize final image size.

**Pattern:**
```dockerfile
# Stage 1: Build
FROM build-image AS builder
RUN compile application

# Stage 2: Runtime
FROM minimal-runtime-image
COPY --from=builder /app/binary /app/
CMD ["/app/binary"]
```

**Benefits:**
- 80-95% smaller images (excludes build tools)
- Improved security (no compilers in production)
- Faster deployments
- Better layer caching

### Base Image Selection

**Decision matrix:**

The rest: https://github.com/ancoleman/ai-design-components/blob/HEAD/skills/writing-dockerfiles/SKILL.md