Architecture

High-Level

• FastAPI handles HTTP requests and validates payloads.
• SQLAlchemy persists state in Postgres.
• Celery processes background jobs reliably (separate worker process).
• Redis acts as the Celery broker/result backend.

Module Layout

• diagnostics_lab/main.py
• app factory (create_app) + router wiring
• diagnostics_lab/settings.py
• typed settings loaded from env (.env supported)
• diagnostics_lab/db/
• session.py engine + session factory
• models/ ORM models
• diagnostics_lab/api/
• deps.py shared dependencies (db session, current user, role checks)
• routes/ API routers grouped by domain
• diagnostics_lab/celery_app.py
• Celery app configuration + beat schedule
• diagnostics_lab/tasks.py
• asynchronous processing (result interpretation, order roll-up)

Patterns Used

Dependency Injection

• DB session: Depends(get_db)
• Auth: Depends(get_current_user)
• Role checks: Depends(require_role("admin"))

"Write fast, enrich later" with Celery

• API endpoints persist the minimal data quickly.
• Celery tasks perform:
• derived fields (interpretation)
• cross-entity rollups (order status)

This prevents long-running requests and isolates background work.