2nd/10_Wiki/Topics/Architecture/Software Architecture Documentation.md

---
id: wiki-2026-0508-software-architecture-documentat
title: Software Architecture Documentation
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [SAD, Architecture Documentation, arc42, C4 Model]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [architecture, documentation, arc42, c4, adr]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: markdown
  framework: structurizr
---

# Software Architecture Documentation

## 매 한 줄
> **"매 architecture 의 communicate 가능 form 의 capture — 매 stakeholder 의 different view 의 serve."**. 매 arc42 (12-section template), C4 (4-level zoom), 4+1 view (logical/process/dev/physical+scenario), ADR (decision log) 의 4 매 dominant frameworks. 매 2026 modern: Structurizr DSL 의 diagrams-as-code, AsyncAPI 의 event arch documentation.

## 매 핵심

### 매 frameworks
- **arc42** — 12 sections (introduction → goals → context → solution strategy → blocks → runtime → deployment → concepts → decisions → quality → risks → glossary).
- **C4 Model** (Brown) — Context / Containers / Components / Code (zoom levels).
- **4+1 View** (Kruchten) — Logical, Process, Development, Physical, +Scenarios.
- **ADR** (Nygard) — decision log per technical choice.

### 매 audiences
- Executives → context view (C4 L1).
- Developers → containers + components.
- Ops → deployment view + runbook.
- Auditors → cross-cutting concerns + decisions.

### 매 응용
1. New service onboarding doc.
2. M&A architecture due diligence.
3. SOC2 / ISO27001 audit evidence.
4. Pre-rewrite reverse-architecting.
5. Onboarding new engineer (1-week ramp).

## 💻 패턴

### arc42 skeleton (markdown)
```markdown
# Architecture Documentation — Service X

## 1. Introduction & Goals
## 2. Constraints
## 3. Context & Scope
## 4. Solution Strategy
## 5. Building Block View
## 6. Runtime View
## 7. Deployment View
## 8. Crosscutting Concepts
## 9. Architecture Decisions (ADRs)
## 10. Quality Requirements
## 11. Risks & Technical Debt
## 12. Glossary
```

### C4 with Structurizr DSL
```dsl
workspace "Skybound" {
  model {
    user = person "Customer"
    api = softwareSystem "API" {
      web = container "Web App" "React"
      svc = container "Backend" "Node.js"
      db = container "Database" "Postgres"
    }
    user -> web "uses"
    web -> svc "JSON/HTTPS"
    svc -> db "SQL"
  }
  views {
    systemContext api { include * autolayout }
    container api { include * autolayout }
  }
}
```

### ADR template (MADR)
```markdown
# ADR-0042: Use Postgres as Primary Store

## Status
Accepted (2026-05-10)

## Context
Need transactional store with strong consistency, JSON support.

## Decision
Use Postgres 16 with logical replication for read-replicas.

## Consequences
+ ACID, mature ecosystem, JSONB
- Vertical scaling ceiling — sharding plan needed by 2027

## Alternatives
- DynamoDB: rejected (relational queries)
- Mongo: rejected (consistency tradeoffs)
```

### Diagrams-as-code (Mermaid)
```markdown
```mermaid
C4Container
  title Container Diagram for Skybound
  Person(user, "User")
  System_Boundary(api, "Skybound") {
    Container(web, "Web App", "React")
    Container(svc, "Backend", "Node.js")
    ContainerDb(db, "Database", "Postgres")
  }
  Rel(user, web, "uses")
  Rel(web, svc, "JSON/HTTPS")
  Rel(svc, db, "SQL")
```
```

### AsyncAPI (event arch)
```yaml
asyncapi: 3.0.0
info: { title: Orders, version: 1.0.0 }
channels:
  orderPlaced:
    address: orders.placed
    messages:
      OrderPlaced:
        payload:
          type: object
          properties:
            id: { type: string }
            amount: { type: number }
```

### Quality attribute scenarios
```markdown
## Performance Scenario
- Source: 10k concurrent users
- Stimulus: checkout submit
- Environment: peak load
- Response: order created, confirmation email queued
- Measure: p99 < 800ms, error rate < 0.1%
```

### Documentation in repo (docs-as-code)
```
/docs
  /architecture
    arc42.md
    /adr
      0001-postgres.md
      0002-event-bus.md
    /diagrams
      workspace.dsl
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| Quick visual onboarding | C4 Context + Container |
| Comprehensive system doc | arc42 full template |
| Per-decision rationale | ADR (MADR) |
| Event-driven system | AsyncAPI + arc42 ch.6 |
| Audit evidence | arc42 ch.8 + ADRs |

**기본값**: arc42 + C4 (L1-L2) + ADR repo + Structurizr DSL + docs-as-code in monorepo.

## 🔗 Graph
- 부모: [[Software-Architecture]]
- 변형: [[arc42]] · [[C4 Model (Architecture Documentation)]]
- 응용: [[ADR]] · [[Structurizr]] · [[Mermaid Diagrams]]
- Adjacent: [[Architecture Decision Record]] · [[Software Architecture Erosion]]

## 🤖 LLM 활용
**언제**: doc gap analysis, ADR drafting, view-completeness review.
**언제 X**: 매 architecture 의 yet 결정 X — 매 decision-making 의 first.

## ❌ 안티패턴
- **Stale Visio**: 매 PDF/image 의 versioned X — diagrams-as-code 사용.
- **Doc-only, no view**: 매 1 PDF 의 dump — view-per-audience 분리.
- **No ADR**: 매 6개월 후 매 "왜 X 선택?" 답 X.

## 🧪 검증 / 중복
- Verified (arc42.org, C4model.com, Brown "Software Architecture for Developers", Nygard ADR).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — arc42, C4, ADR, AsyncAPI, docs-as-code patterns |