2nd/10_Wiki/Topics/Architecture/Architectural-Constraint-Enforcement.md

---
id: wiki-2026-0508-architectural-constraint-enforce
title: Architectural Constraint Enforcement
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [archunit, dependency-cruiser, fitness-functions]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [architecture, fitness-functions, archunit, constraints]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: java
  framework: archunit
---

# Architectural Constraint Enforcement

## 매 한 줄
> **"매 architecture 의 자동으로 enforce 한다"**. 매 ArchUnit (2018, Java/Kotlin), Dependency-Cruiser (JS/TS), NetArchTest (.NET), Konsist (Kotlin) 의 fitness function 의 CI 통합. 매 *Building Evolutionary Architectures* (Ford, Parsons, Kua, 2017; 2nd ed 2023) 의 paradigm.

## 매 핵심

### 매 enforced rules (typical)
- **Layer dependency**: 매 controller → service → repository — 매 reverse 의 X.
- **Package isolation**: `domain` 의 framework import 의 X.
- **Naming**: 매 `*Service` class 의 `service` package 의 only.
- **Cyclic dependency**: 매 always X.
- **API surface**: 매 `internal/*` 의 external module 의 import 의 X.

### 매 fitness function categories (Ford)
- **Atomic vs Holistic**: single attribute / system-wide.
- **Triggered vs Continual**: CI gate / runtime probe.
- **Static vs Dynamic**: code analysis / runtime metric.
- **Automated vs Manual**: prefer automated.

### 매 응용
1. CI gate — 매 PR 의 violation 의 block.
2. Refactor safety — 매 large refactor 의 invariant 의 hold.
3. Onboarding — 매 implicit rule 의 explicit code 의 됨.

## 💻 패턴

### ArchUnit — layer enforcement (Java)
```java
import static com.tngtech.archunit.lang.syntax.ArchRuleDefinition.*;
import com.tngtech.archunit.junit.AnalyzeClasses;
import com.tngtech.archunit.junit.ArchTest;
import com.tngtech.archunit.lang.ArchRule;

@AnalyzeClasses(packages = "com.acme.banking")
class LayerArchTest {
  @ArchTest
  static final ArchRule controllers_only_call_services =
    classes().that().resideInAPackage("..controller..")
      .should().onlyDependOnClassesThat()
      .resideInAnyPackage("..controller..", "..service..", "java..", "org.springframework..");

  @ArchTest
  static final ArchRule no_cycles =
    slices().matching("..banking.(*)..").should().beFreeOfCycles();

  @ArchTest
  static final ArchRule services_named_correctly =
    classes().that().resideInAPackage("..service..")
      .and().areNotInterfaces()
      .should().haveSimpleNameEndingWith("Service");
}
```

### Dependency-Cruiser (TypeScript)
```js
// .dependency-cruiser.cjs
module.exports = {
  forbidden: [
    {
      name: 'no-circular',
      severity: 'error',
      from: {},
      to: { circular: true }
    },
    {
      name: 'domain-pure',
      severity: 'error',
      from: { path: '^src/domain' },
      to: { path: '^(src/infra|node_modules/express)' }
    },
    {
      name: 'no-test-in-prod',
      severity: 'error',
      from: { pathNot: '\\.test\\.ts$' },
      to: { path: '\\.test\\.ts$' }
    }
  ],
  options: { tsConfig: { fileName: 'tsconfig.json' } }
};
```

```bash
npx depcruise src --config .dependency-cruiser.cjs
npx depcruise src --output-type dot | dot -T svg > deps.svg
```

### NetArchTest (.NET 8)
```csharp
using NetArchTest.Rules;
using Xunit;

public class ArchitectureTests {
  [Fact]
  public void Domain_ShouldNotDependOnInfrastructure() {
    var result = Types.InAssembly(typeof(Domain.Marker).Assembly)
      .That().ResideInNamespace("Acme.Domain")
      .ShouldNot().HaveDependencyOn("Acme.Infrastructure")
      .GetResult();
    Assert.True(result.IsSuccessful, string.Join(",", result.FailingTypeNames ?? []));
  }
}
```

### Konsist (Kotlin)
```kotlin
import com.lemonappdev.konsist.api.Konsist
import com.lemonappdev.konsist.api.verify.assertTrue

class CleanArchitectureTest {
  @Test
  fun `domain layer does not depend on data layer`() {
    Konsist.scopeFromProduction()
      .files
      .filter { it.packagee?.fullyQualifiedName?.contains("domain") == true }
      .assertTrue { file ->
        file.imports.none { it.name.contains(".data.") }
      }
  }
}
```

### Go — go-arch-lint
```yaml
# .go-arch-lint.yml
version: 3
workdir: internal
components:
  domain: { in: domain/** }
  app:    { in: app/** }
  infra:  { in: infra/** }
deps:
  domain: {}
  app:    { mayDependOn: [domain] }
  infra:  { mayDependOn: [domain, app] }
```

### Python — import-linter
```ini
# .importlinter
[importlinter]
root_package = acme

[importlinter:contract:layers]
name = Layered architecture
type = layers
layers =
    acme.api
    acme.service
    acme.domain
```

### CI integration (GitHub Actions)
```yaml
- name: Architecture tests
  run: |
    ./gradlew archTest
    npx depcruise src --config .dependency-cruiser.cjs
    lint-imports
```

## 매 결정 기준
| Stack | Tool |
|---|---|
| Java/Kotlin | ArchUnit, Konsist |
| JS/TS | Dependency-Cruiser, eslint-plugin-boundaries |
| .NET | NetArchTest |
| Go | go-arch-lint |
| Python | import-linter |
| Polyglot | Sonargraph, Structure101 (commercial) |

**기본값**: 매 ArchUnit (JVM) / Dependency-Cruiser (Node) — 매 OSS + CI-first.

## 🔗 Graph
- 부모: [[Software Architecture]] · [[Fitness Functions]]
- 변형: [[Static-Analysis]]
- 응용: [[CI-CD]] · [[Architecture_Refactor]]
- Adjacent: [[Architecture Erosion (아키텍처 침식)]] · [[Modular-Monolith]]

## 🤖 LLM 활용
**언제**: 매 plain English rule → ArchUnit/depcruise config 의 translation, 매 violation message 의 fix suggestion.
**언제 X**: 매 architecture 의 design 의 LLM-only delegation — 매 human ownership 의 필수.

## ❌ 안티패턴
- **Test exists, never runs**: 매 CI 의 not wired — 매 dead rule.
- **Over-broad rule**: 매 100% violations 의 noise — 매 graduated rollback (allowlist).
- **Rule without rationale**: 매 ADR-less rule — 매 future deletion 의 blocker.
- **Ignore-list explosion**: 매 exception 의 100+ — 매 architecture 의 already eroded 의 sign.

## 🧪 검증 / 중복
- Verified (Ford et al., *Building Evolutionary Architectures* 2nd ed; ArchUnit user guide).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — fitness functions + ArchUnit/depcruise/NetArchTest patterns |