Antigravity Agent
195 lines
6.7 KiB
Markdown
195 lines
6.7 KiB
Markdown
---
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id: wiki-2026-0508-비기능-요구사항-non-functional-requirem
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title: 비기능 요구사항 (Non-functional Requirements)
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category: 10_Wiki/Topics
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status: verified
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canonical_id: self
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aliases: [NFR, Non-functional Requirements, Quality Attributes, -ilities]
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duplicate_of: none
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source_trust_level: A
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confidence_score: 0.9
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verification_status: applied
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tags: [architecture, requirements, quality-attributes, nfr, sre]
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raw_sources: []
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last_reinforced: 2026-05-10
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github_commit: pending
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tech_stack:
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language: YAML/SQL
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framework: SLO frameworks (Google SRE)
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---
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# 비기능 요구사항 (Non-functional Requirements, NFRs)
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## 매 한 줄
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> **"매 NFR은 시스템이 *어떻게* 동작해야 하는가의 명세이며 매 architecture는 NFR 의 함수다"**. 매 functional requirement 가 *what* 이라면 NFR 은 *how-well*; 매 ISO 25010 quality model 이 2026 의 표준이며 매 SLO/SLI 형태로 measurable 화 된다.
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## 매 핵심
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### 매 ISO/IEC 25010 quality attributes
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- **Performance efficiency**: time behaviour, resource utilization, capacity.
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- **Reliability**: availability, fault tolerance, recoverability, maturity.
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- **Security**: confidentiality, integrity, non-repudiation, authenticity, accountability.
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- **Maintainability**: modularity, reusability, analyzability, modifiability, testability.
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- **Portability**: adaptability, installability, replaceability.
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- **Compatibility**: co-existence, interoperability.
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- **Usability**: learnability, operability, accessibility.
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- **Functional suitability**: completeness, correctness, appropriateness.
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### 매 measurable 화
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- **SLI**: 매 service-level indicator (latency p99, error rate, availability ratio).
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- **SLO**: 매 service-level objective (99.9% over 30d, p99 < 250ms).
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- **SLA**: 매 contract with consequences (penalty, refund).
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- **Error budget**: 매 1 - SLO; 매 deploy/feature freeze trigger.
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### 매 응용
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1. 매 NFR-driven architecture: cache for performance, replication for availability, audit log for accountability.
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2. 매 NFR-driven test: load test, chaos engineering, security pentest, accessibility audit.
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3. 매 NFR-driven trade-off: CAP theorem (consistency vs availability), latency vs throughput.
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## 💻 패턴
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### NFR specification (FURPS+)
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```yaml
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nfr:
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performance:
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latency_p99_ms: 250
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throughput_rps: 1000
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cpu_utilization_max: 0.7
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availability:
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slo: 99.95
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measurement_window: 30d
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error_budget_min_per_quarter: 0.001
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security:
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auth: OAuth2 + PKCE
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transport: TLS 1.3 only
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data_at_rest: AES-256-GCM
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audit_log_retention: 7y
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scalability:
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horizontal: 10x peak in 5min
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observability:
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log_format: JSON, OpenTelemetry
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trace_sampling: 0.1
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```
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### SLO definition (Prometheus)
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```yaml
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- alert: APILatencyBudgetBurn
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expr: |
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(
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histogram_quantile(0.99,
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sum(rate(http_request_duration_seconds_bucket{job="api"}[5m])) by (le))
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> 0.25
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)
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for: 10m
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annotations:
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summary: p99 latency exceeds 250ms SLO
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```
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### Multi-burn-rate alert
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```yaml
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# Google SRE multi-window multi-burn-rate
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- alert: ErrorBudgetFastBurn
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expr: |
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(
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sum(rate(http_requests_total{status=~"5.."}[1h]))
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/ sum(rate(http_requests_total[1h]))
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) > (14.4 * (1 - 0.999))
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AND
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(
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sum(rate(http_requests_total{status=~"5.."}[5m]))
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/ sum(rate(http_requests_total[5m]))
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) > (14.4 * (1 - 0.999))
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```
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### Performance budget (frontend)
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```javascript
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// budget.config.js — Lighthouse CI
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module.exports = {
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ci: {
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assert: {
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assertions: {
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'first-contentful-paint': ['error', { maxNumericValue: 1800 }],
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'largest-contentful-paint': ['error', { maxNumericValue: 2500 }],
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'total-blocking-time': ['error', { maxNumericValue: 200 }],
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'cumulative-layout-shift': ['error', { maxNumericValue: 0.1 }],
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},
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},
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},
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};
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```
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### Resilience: circuit breaker
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```typescript
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class CircuitBreaker<T> {
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private failures = 0;
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private state: 'closed'|'open'|'half-open' = 'closed';
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private openedAt = 0;
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constructor(private fn: () => Promise<T>, private threshold = 5, private cooldownMs = 30_000) {}
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async call(): Promise<T> {
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if (this.state === 'open') {
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if (Date.now() - this.openedAt > this.cooldownMs) this.state = 'half-open';
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else throw new Error('circuit-open');
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}
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try {
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const r = await this.fn();
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this.failures = 0;
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this.state = 'closed';
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return r;
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} catch (e) {
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if (++this.failures >= this.threshold) {
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this.state = 'open';
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this.openedAt = Date.now();
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}
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throw e;
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}
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}
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}
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```
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### Accessibility audit (a11y NFR)
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```typescript
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// axe-core CI gate
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import { AxePuppeteer } from '@axe-core/puppeteer';
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const results = await new AxePuppeteer(page).analyze();
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const critical = results.violations.filter(v => v.impact === 'critical');
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if (critical.length > 0) throw new Error(`a11y: ${critical.length} critical violations`);
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```
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## 매 결정 기준
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| 상황 | Approach |
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|---|---|
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| Public API | Latency + availability SLO + rate limit |
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| Financial system | Strong consistency + audit log + 7y retention |
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| Mobile app | Battery + bundle size + offline-first |
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| B2B SaaS | Multi-tenant isolation + SOC2 + 99.9% SLA |
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| Real-time game | p99 latency + tick budget + recoverability |
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**기본값**: 매 SMART NFR (Specific, Measurable, Achievable, Relevant, Time-bounded) + SLO 형태로 명세.
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## 🔗 Graph
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- 부모: [[Software Architecture]] · [[Requirements Engineering]]
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- 변형: [[Performance Requirements]] · [[Security Requirements]] · [[Availability Requirements]]
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- 응용: [[ATAM (Architecture Trade-offs Analysis Method)]] · [[소프트웨어 아키텍처 평가 (Software Architecture Evaluation)]]
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- Adjacent: [[SLO]] · [[Error Budget]] · [[Chaos Engineering]] · [[복잡한 비즈니스 도메인 (금융 헬스케어 이커머스 등)]]
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## 🤖 LLM 활용
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**언제**: 매 NFR elicitation workshop, SLO/SLI draft, ISO 25010 mapping, NFR-to-architecture trace matrix.
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**언제 X**: 매 binding SLA terms (legal review 필수), 매 actual production SLO measurement (instrumentation 필요).
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## ❌ 안티패턴
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- **Wishlist NFR**: 매 "fast", "secure", "scalable" — non-measurable.
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- **NFR as afterthought**: 매 sprint 끝에 retrofit → architectural rewrite 발생.
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- **One-size SLO**: 매 모든 endpoint 99.99% → cost 폭증.
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- **No error budget**: 매 SLO 만 있고 budget consumption tracking 없음 → meaningless.
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- **Gold-plating reliability**: 매 needed 99.9% 위 99.999% pursuit → 100x cost.
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## 🧪 검증 / 중복
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- Verified (ISO/IEC 25010:2023, Google SRE Book Ch.4, Bass et al. "Software Architecture in Practice" 4ed).
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- 신뢰도 A.
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## 🕓 Changelog
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| 날짜 | 변경 |
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| 2026-05-08 | Phase 1 |
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| 2026-05-10 | Manual cleanup — ISO 25010 + SLO/SLI + NFR specification patterns |
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