Antigravity Agent
150 lines
4.9 KiB
Markdown
150 lines
4.9 KiB
Markdown
---
|
|
id: wiki-2026-0508-feature-flags
|
|
title: Feature Flags
|
|
category: 10_Wiki/Topics
|
|
status: verified
|
|
canonical_id: self
|
|
aliases: [Feature Toggles, Feature Switches, Feature Gates]
|
|
duplicate_of: none
|
|
source_trust_level: A
|
|
confidence_score: 0.9
|
|
verification_status: applied
|
|
tags: [devops, deployment, experimentation, release-engineering]
|
|
raw_sources: []
|
|
last_reinforced: 2026-05-10
|
|
github_commit: pending
|
|
tech_stack:
|
|
language: TypeScript/Go
|
|
framework: LaunchDarkly/Unleash/OpenFeature
|
|
---
|
|
|
|
# Feature Flags
|
|
|
|
## 매 한 줄
|
|
> **"매 deploy 와 release 를 매 분리하는 runtime conditional"**. Pete Hodgson 의 매 4-axis taxonomy (release/experiment/ops/permission) 가 매 baseline. 매 modern stack — OpenFeature spec + provider (LaunchDarkly, Unleash, ConfigCat, Statsig) — 매 progressive delivery, A/B test, kill switch 의 매 통합 layer.
|
|
|
|
## 매 핵심
|
|
|
|
### 매 4 종류 (Hodgson)
|
|
- **Release toggle**: dark launch, gradual rollout (short-lived).
|
|
- **Experiment toggle**: A/B/n test (medium-lived).
|
|
- **Ops toggle**: kill switch, circuit breaker (medium-lived).
|
|
- **Permission toggle**: per-user/tenant entitlement (long-lived).
|
|
|
|
### 매 axis
|
|
- Lifetime: hours ↔ years.
|
|
- Dynamism: build-time → runtime → request-time.
|
|
- Scope: global → user → request.
|
|
|
|
### 매 응용
|
|
1. Trunk-based development + dark launch.
|
|
2. Canary / progressive rollout (1% → 100%).
|
|
3. Kill switch (incident mitigation).
|
|
4. A/B testing & holdout group.
|
|
5. Tier-based feature gating (free/pro/enterprise).
|
|
|
|
## 💻 패턴
|
|
|
|
### OpenFeature SDK (vendor-neutral)
|
|
```typescript
|
|
import { OpenFeature } from '@openfeature/server-sdk';
|
|
import { LaunchDarklyProvider } from '@openfeature/launchdarkly-server-provider';
|
|
|
|
await OpenFeature.setProviderAndWait(new LaunchDarklyProvider(SDK_KEY));
|
|
const client = OpenFeature.getClient();
|
|
|
|
const showNew = await client.getBooleanValue('new-checkout', false, {
|
|
targetingKey: user.id,
|
|
email: user.email,
|
|
plan: user.plan,
|
|
});
|
|
return showNew ? renderNewCheckout() : renderOldCheckout();
|
|
```
|
|
|
|
### Percentage rollout (deterministic hash)
|
|
```go
|
|
import "hash/fnv"
|
|
func rollout(flagKey, userID string, percent int) bool {
|
|
h := fnv.New32a()
|
|
h.Write([]byte(flagKey + ":" + userID))
|
|
return int(h.Sum32()%100) < percent
|
|
}
|
|
// Same user → same bucket across calls (sticky).
|
|
```
|
|
|
|
### Kill switch (ops toggle)
|
|
```typescript
|
|
async function fetchRecommendations(userId: string) {
|
|
if (await flags.getBooleanValue('reco-kill-switch', false)) {
|
|
return []; // disable the feature instantly during incident
|
|
}
|
|
return recoService.fetch(userId);
|
|
}
|
|
```
|
|
|
|
### Multivariate experiment
|
|
```typescript
|
|
const variant = await client.getStringValue('checkout-variant', 'control', ctx);
|
|
switch (variant) {
|
|
case 'one-click': return <OneClickCheckout />;
|
|
case 'wallet': return <WalletCheckout />;
|
|
default: return <StandardCheckout />;
|
|
}
|
|
metrics.track('checkout_view', { variant, userId });
|
|
```
|
|
|
|
### Local override (dev/test)
|
|
```typescript
|
|
if (process.env.NODE_ENV === 'development') {
|
|
OpenFeature.setProvider(new InMemoryProvider({
|
|
'new-checkout': { defaultVariant: 'on', variants: { on: true, off: false } },
|
|
}));
|
|
}
|
|
```
|
|
|
|
### Flag cleanup (technical debt)
|
|
```bash
|
|
# Find old flags
|
|
rg "getBooleanValue\\('old-checkout'" --type ts
|
|
# Provider audit: list flags > 90 days old, no recent eval, 100% rollout → delete.
|
|
```
|
|
|
|
## 매 결정 기준
|
|
| 상황 | Approach |
|
|
|---|---|
|
|
| Dark launch / gradual | Release toggle, percentage rollout |
|
|
| Hypothesis test | Experiment toggle + analytics |
|
|
| Incident mitigation | Ops toggle (always available) |
|
|
| Tier / paid features | Permission toggle (long-lived) |
|
|
| Build-time only | Compile flag (no runtime cost) |
|
|
|
|
**기본값**: OpenFeature SDK + managed provider (LaunchDarkly/Unleash). Kill switch 모든 critical path 에 매.
|
|
|
|
## 🔗 Graph
|
|
- 부모: [[Continuous Delivery]] · [[Progressive Delivery]]
|
|
- 변형: [[Release Toggle]] · [[Experiment Toggle]] · [[Kill Switch]]
|
|
- 응용: [[Canary Deployment]] · [[A/B Testing]] · [[Trunk-based Development]]
|
|
- Adjacent: [[OpenFeature]] · [[LaunchDarkly]] · [[Unleash]] · [[Statsig]]
|
|
|
|
## 🤖 LLM 활용
|
|
**언제**: Release strategy 설계, incident playbook, experiment platform 평가.
|
|
**언제 X**: Static config — env var / config file 충분.
|
|
|
|
## ❌ 안티패턴
|
|
- **Flag debt**: 100% rolled-out flag 를 매 안 지움 → cyclomatic complexity 폭발.
|
|
- **Nested flags**: A&&B&&C — 매 test space 매 explosion.
|
|
- **Flag in hot loop**: per-request eval 의 매 latency — cache locally.
|
|
- **No fallback**: provider 다운 시 feature 깨짐 — default + cached value.
|
|
- **Flag = config 오용**: 진짜 config 는 매 config service 로.
|
|
- **No analytics linkage**: experiment 인데 evaluation 안 records.
|
|
|
|
## 🧪 검증 / 중복
|
|
- Verified (martinfowler.com Feature Toggles, OpenFeature spec, LaunchDarkly docs).
|
|
- 신뢰도 A.
|
|
|
|
## 🕓 Changelog
|
|
| 날짜 | 변경 |
|
|
|---|---|
|
|
| 2026-05-08 | Phase 1 |
|
|
| 2026-05-10 | Manual cleanup — 4-axis taxonomy + OpenFeature/percentage/kill-switch 패턴 |
|