app = FastAPI() def get_db(): db = SessionLocal() try: yield db finally: db.close() def heavy_text_parser(file_id: int, db: Session): # Parsing a file that takes 5 minutes parse_and_save(file_id, db) @app.post("/upload") async def upload_file( background_tasks: BackgroundTasks, db: Session = Depends(get_db) ): file_id = save_file_to_db(db) db.commit() background_tasks.add_task(heavy_text_parser, file_id, db) return {"status": "parsing started"}