gobetterauth/use-cases-and-orchestration

Use Cases & Orchestration

When to use this skill

• Implement workflows that span multiple services
• Encapsulate complex authentication or account operations
• Define reusable operations that handlers invoke
• Keep handlers thin by moving logic into use cases

Key principles

1. Service orchestration: Use cases call multiple services
2. Business-focused: Methods represent user actions, not HTTP operations
3. Dependency injection: Services passed at construction
4. Pure domain: No HTTP, no routing, just business logic
5. Testable: Can be tested independently by mocking services

Pattern

Use cases orchestrate services:

• Define request/response types
• Implement as structs with service dependencies
• Single public Execute or action method
• Handle validation such as checking request parameters
• Coordinate multiple services sequentially
• Handle errors and return domain models

Example

See examples/todo_usecases.go for:

• CreateTodoUseCase orchestrating TodoService
• MarkTodoCompleteUseCase patterns
• Request/response types and error handling

Common mistakes

1. Use cases returning HTTP status codes
2. Validation in handlers instead of use cases
3. Use cases calling other use cases
4. Creating new services instead of injecting
5. Use cases with no clear purpose

References

• internal/usecases/ - Core use cases
• plugins/email-password/usecases/ - Plugin use case examples
• plugins/email-password/types/ - Request/response types