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[Project Name] - Technical Design Document (TDD)

Status: Draft | Review | Approved | Implemented Author: [Name] Date: YYYY-MM-DD Related: [Solution Proposal, ADRs, Epic]

Overview​

Kurze Zusammenfassung: Was wird gebaut?

Scope: [Was ist Teil dieses Designs] Out of Scope: [Was bewusst nicht behandelt wird]

Architecture​

System Context​

# Context Diagram: Wo sitzt das System im größeren Ökosystem?
# Import colors: ...@../../../assets/colors/_colors.d2

[System] -> [External Systems]
[Users] -> [System]

Component Architecture​

# Detaillierte Komponentenarchitektur
# Import colors: ...@../../../assets/colors/_colors.d2

[Frontend]
[Backend Services]
[Data Layer]
[Integration Points]

Key Design Decisions​

AspektEntscheidungBegründungAlternativen
[Datenbank][PostgreSQL][Reasoning][MySQL, MongoDB]
[API Style][REST][Reasoning][GraphQL, gRPC]
[Auth][OAuth2 + JWT][Reasoning][Session-based, SAML]

Data Model​

Entities​

// Beispiel: Entity-Definitionen
public class Order
{
    public Guid Id { get; set; }
    public DateTime CreatedAt { get; set; }
    public OrderStatus Status { get; set; }
    // ...
}

Database Schema​

  • Tables: [Liste der Haupttabellen]
  • Relationships: [ER-Diagram oder Beschreibung]
  • Indices: [Performance-kritische Indices]
  • Migrations: [Strategie für Schema-Änderungen]

API Contracts​

REST Endpoints​

Create Order​

POST /api/v1/orders
Content-Type: application/json
Authorization: Bearer <token>

{
  "customerId": "uuid",
  "items": [...]
}

Response 201 Created:
{
  "orderId": "uuid",
  "status": "pending",
  "createdAt": "2025-01-01T10:00:00Z"
}

Get Order Status​

GET /api/v1/orders/{orderId}
Authorization: Bearer <token>

Response 200 OK:
{
  "orderId": "uuid",
  "status": "completed",
  "items": [...]
}

Integration Points​

SystemProtokollZweckError Handling
[Partner API]REST/HTTPS[Datenaustausch][Retry, Fallback]
[Message Queue]AMQP[Async Processing][Dead Letter Queue]

Sequence Diagrams​

Happy Path: Order erstellen​

# Sequence: User creates order
# Import colors: ...@../../../assets/colors/_colors.d2

User -> Frontend: Submit Order
Frontend -> Backend: POST /api/orders
Backend -> Database: Insert Order
Backend -> Queue: Publish OrderCreated Event
Backend -> Frontend: 201 Created
Frontend -> User: Order Confirmation

Error Case: Validation Failure​

# Sequence: Invalid order data
# Import colors: ...@../../../assets/colors/_colors.d2

User -> Frontend: Submit Invalid Order
Frontend -> Backend: POST /api/orders
Backend -> Backend: Validate (FAIL)
Backend -> Frontend: 400 Bad Request
Frontend -> User: Error Message

Security & Auth​

  • Authentication: [Methode, Token-Handling]
  • Authorization: [RBAC, Claims, Policies]
  • Data Protection: [Encryption at rest/in transit]
  • OWASP Top 10: [Maßnahmen gegen XSS, SQL Injection, etc.]

Error Handling​

Error TypeHTTP StatusRetry StrategyUser Message
Validation400No[Feldspezifisch]
Auth Failure401No"Nicht autorisiert"
Rate Limit429Yes (backoff)"Zu viele Anfragen"
Server Error500Yes (3x)"Technischer Fehler"

Performance & Scalability​

  • Load Expectations: [Requests/sec, Data Volume]
  • Caching Strategy: [Redis, CDN, In-Memory]
  • Database Optimization: [Indices, Query-Pläne]
  • Horizontal Scaling: [Load Balancer, Stateless Services]

Testing Strategy​

  • Unit Tests: [Coverage-Ziel, Frameworks]
  • Integration Tests: [API Tests, Contract Tests]
  • E2E Tests: [Smoke Tests, Critical Paths]
  • Performance Tests: [Load Testing, Benchmarks]

Deployment & Operations​

  • Environments: [Dev, Test, Prod]
  • CI/CD Pipeline: [Build, Test, Deploy Steps]
  • Monitoring: [Health Checks, Metrics, Alerts]
  • Logging: [Structured Logging, Correlation IDs]
  • Rollback Strategy: [Blue/Green, Canary]

Open Questions​

  • [Frage 1: zu klären mit Team X]
  • [Frage 2: Architektur-Entscheidung ausstehend]
  • [Frage 3: Performance-Tests notwendig]

Appendix​

Review Sign-Off:

RoleNameDateApproved
Architect[Name]YYYY-MM-DD✅ / ❌
Lead Dev[Name]YYYY-MM-DD✅ / ❌
Security[Name]YYYY-MM-DD✅ / ❌