사용 방법
- 설치 명령을 복사하고 자신의 에이전트 환경에 설치하기 전에 소스 패키지를 확인하세요.
- 필요한 도구, 인증 정보, 지원 환경은 원본 문서에서 확인하세요.
- 입력과 원하는 산출물을 설명하고 출처와 결과를 대조하세요.
npx skills add https://github.com/actionbook/rust-skills --skill m09-domain시작 전 확인
- 설치에는 모델 구독, API 한도, 파일 접근 권한이 포함되지 않습니다.
- 별점 수와 설치 수는 활동 지표이며 독립적인 품질·보안 검증이 아닙니다.
원본 Skill 문서
원본 저장소의 제목, 예시, 코드, 표, 링크, 이미지를 유지해 표시합니다.
Domain Modeling
Layer 2: Design Choices
Core Question
What is this concept's role in the domain?
Before modeling in code, understand:
- Is it an Entity (identity matters) or Value Object (interchangeable)?
- What invariants must be maintained?
- Where are the aggregate boundaries?
Domain Concept → Rust Pattern
| Domain Concept | Rust Pattern | Ownership Implication |
|---|---|---|
| Entity | struct + Id | Owned, unique identity |
| Value Object | struct + Clone/Copy | Shareable, immutable |
| Aggregate Root | struct owns children | Clear ownership tree |
| Repository | trait | Abstracts persistence |
| Domain Event | enum | Captures state changes |
| Service | impl block / free fn | Stateless operations |
Thinking Prompt
Before creating a domain type:
- What's the concept's identity?
- Needs unique identity → Entity (Id field)
- Interchangeable by value → Value Object (Clone/Copy)
- What invariants must hold?
- Always valid → private fields + validated constructor
- Transition rules → type state pattern
- Who owns this data?
- Single owner (parent) → owned field
- Shared reference → Arc/Rc
- Weak reference → Weak
Trace Up ↑
To domain constraints (Layer 3):
"How should I model a Transaction?"
↑ Ask: What domain rules govern transactions?
↑ Check: domain-fintech (audit, precision requirements)
↑ Check: Business stakeholders (what invariants?)| Design Question | Trace To | Ask |
|---|---|---|
| Entity vs Value Object | domain-* | What makes two instances "the same"? |
| Aggregate boundaries | domain-* | What must be consistent together? |
| Validation rules | domain-* | What business rules apply? |
Trace Down ↓
To implementation (Layer 1):
"Model as Entity"
↓ m01-ownership: Owned, unique
↓ m05-type-driven: Newtype for Id
"Model as Value Object"
↓ m01-ownership: Clone/Copy OK
↓ m05-type-driven: Validate at construction
"Model as Aggregate"
↓ m01-ownership: Parent owns children
↓ m02-resource: Consider Rc for shared within aggregateQuick Reference
| DDD Concept | Rust Pattern | Example |
|---|---|---|
| Value Object | Newtype | struct Email(String); |
| Entity | Struct + ID | struct User { id: UserId, ... } |
| Aggregate | Module boundary | mod order { ... } |
| Repository | Trait | trait UserRepo { fn find(...) } |
| Domain Event | Enum | enum OrderEvent { Created, ... } |
Pattern Templates
Value Object
rust
struct Email(String);
impl Email {
pub fn new(s: &str) -> Result<Self, ValidationError> {
validate_email(s)?;
Ok(Self(s.to_string()))
}
}Entity
rust
struct UserId(Uuid);
struct User {
id: UserId,
email: Email,
// ... other fields
}
impl PartialEq for User {
fn eq(&self, other: &Self) -> bool {
self.id == other.id // Identity equality
}
}Aggregate
rust
mod order {
pub struct Order {
id: OrderId,
items: Vec<OrderItem>, // Owned children
// ...
}
impl Order {
pub fn add_item(&mut self, item: OrderItem) {
// Enforce aggregate invariants
}
}
}Common Mistakes
| Mistake | Why Wrong | Better |
|---|---|---|
| Primitive obsession | No type safety | Newtype wrappers |
| Public fields with invariants | Invariants violated | Private + accessor |
| Leaked aggregate internals | Broken encapsulation | Methods on root |
| String for semantic types | No validation | Validated newtype |
Related Skills
| When | See |
|---|---|
| Type-driven implementation | m05-type-driven |
| Ownership for aggregates | m01-ownership |
| Domain error handling | m13-domain-error |
| Specific domain rules | domain-* |
