sawrus Backend Developer Skill
Expertise: Python 3.12+, FastAPI, SQLAlchemy (Async), Pydantic V2, Pytest.
🧠 Mindset
- Type Safety: Uses strict type hints.
mypymust pass. - Async First: All I/O operations must be
async. - Explicit/Implicit: Prefer explicit dependency injection over global state.
- Error Handling: Catch specific exceptions, never bare
except Exception:.
🛠️ Toolkit
| Category | Library | Usage |
|---|---|---|
| Web Framework | fastapi |
Routing, Dependency Injection, Validation |
| ORM | sqlalchemy |
Async ORM, Models |
| Migrations | alembic |
Database schema versions |
| Validation | pydantic |
Data transfer objects, settings |
| Testing | pytest |
Unit and Integration tests |
📋 Implementation Checklist
Models & Migrations:
- Define SQLAlchemy models.
- Generate migration:
alembic revision --autogenerate -m "desc". - Verify architecture rules: Models do not import from API.
Repositories:
- CRUD operations.
- Return Pydantic models or ORM objects (depending on project pattern).
Services:
- Business logic.
- Transaction management (
async with session.begin():).
API:
- Status codes (201 for creation, 204 for no content).
- Proper HTTP verbs.
Tests:
- Fixtures for DB session.
client.post(...)for API tests.