2nd/10_Wiki/Topic_Programming/Backend/Case-Study-Skybound-Asset-Cache-Busting.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-case-study-skybound-asset-cache-	Case Study: Skybound Asset Cache Busting	10_Wiki/Topics	verified	self	Cache Busting Asset Versioning Case Study	none	B	0.85	applied	case-study caching deployment web-performance		2026-05-10	pending	language framework TypeScript Vite

Case Study: Skybound Asset Cache Busting

매 한 줄

"매 stale-asset bug 매 production". 매 Skybound (fictional internal codename) 매 CDN-cached JS bundle 매 user device 매 days-old version 의 root-cause hunt → 매 content-hash filename + immutable cache-control headers 의 conventional fix.

매 핵심

매 problem

• 매 deploy → 매 some users 매 broken UI (stale app.js mismatched with new api.js schema).
• 매 CDN-edge 매 7-day cache, browser 매 1-day cache, 매 union 매 race.

매 root cause

• 매 fixed filename /static/app.js 매 invalidation 매 manual.
• 매 Cache-Control: max-age=86400 매 too aggressive for mutable name.

매 fix layers

1. Content-hash in filename: app.[hash].js.
2. Cache-Control: public, max-age=31536000, immutable for hashed assets.
3. Short TTL on index.html (entry point) only.

💻 패턴

Vite hashed output (default)

// vite.config.ts
export default {
  build: {
    rollupOptions: {
      output: {
        entryFileNames: 'assets/[name].[hash].js',
        chunkFileNames: 'assets/[name].[hash].js',
        assetFileNames: 'assets/[name].[hash][extname]',
      },
    },
  },
};

CDN cache-control (Cloudflare worker)

addEventListener('fetch', (e) => e.respondWith(handle(e.request)));
async function handle(req) {
  const url = new URL(req.url);
  const res = await fetch(req);
  const r = new Response(res.body, res);
  if (/\.[a-f0-9]{8,}\.(js|css|png|webp)$/.test(url.pathname)) {
    r.headers.set('Cache-Control', 'public, max-age=31536000, immutable');
  } else if (url.pathname.endsWith('.html') || url.pathname === '/') {
    r.headers.set('Cache-Control', 'public, max-age=60, must-revalidate');
  }
  return r;
}

Service worker cache cleanup

self.addEventListener('activate', (e) => {
  e.waitUntil(
    caches.keys().then(keys =>
      Promise.all(keys.filter(k => k !== CURRENT_VERSION).map(k => caches.delete(k)))
    )
  );
});

Deployment 매 atomic swap (S3 + CloudFront)

aws s3 sync ./dist s3://bucket --cache-control 'public,max-age=31536000,immutable' \
  --exclude 'index.html'
aws s3 cp ./dist/index.html s3://bucket/index.html \
  --cache-control 'public,max-age=60,must-revalidate'
aws cloudfront create-invalidation --distribution-id $ID --paths '/index.html' '/'

Verification 매 post-deploy

curl -I https://app.example.com/assets/app.abc123.js | grep -i cache-control
# expect: cache-control: public, max-age=31536000, immutable

매 결정 기준

Asset type	Strategy
Hashed JS/CSS/images	immutable, max-age=1y
HTML entry	max-age=60, must-revalidate
API JSON	no-store or stale-while-revalidate

기본값: Vite/Webpack hashed output + 1y immutable for hashed, short TTL for HTML.

🔗 Graph

• 변형: ETag
• Adjacent: Vite

🤖 LLM 활용

언제: deploy-time stale-asset bug, CDN config debugging. 언제 X: server-rendered no-cache responses (caching irrelevant).

❌ 안티패턴

• Fixed filenames + long cache: 매 production-broken-on-deploy guarantee.
• Cache-busting via querystring ?v=2: 매 some CDNs ignore query.
• Forgetting HTML cache TTL: hashed assets 매 useless if entry HTML cached.

🧪 검증 / 중복

• Verified (MDN Cache-Control, Vite docs, Web.dev caching guide).
• 신뢰도 B+.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — Skybound case study FULL with Vite + CDN patterns