CODEWITHSUNDEEP
pythonsqlalchemyfastapi
Rafaó
Rafaó

Reputation: 599

Create SQLAlchemy session on event

If I want to use database while processing a request, I make a Dependency Injection like this:

@app.post("/sample_test")
async def sample_test(db: Session = Depends(get_db)):
    return db.query(models.User.height).all()

But I cannot do it with events like this:

@app.on_event("startup")
async def sample_test(db: Session = Depends(get_db)):
    return db.query(models.User.height).all()

because starlette events don't support Depends.

This is my get_db() function:

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

just like in FastAPI manual (https://fastapi.tiangolo.com/tutorial/sql-databases/).

How can I access get_db() inside my event function, so I can work with a Session?

I've tried:

@app.on_event("startup")
async def sample_test(db: Session = Depends(get_db)):
    db = next(get_db())
    return db.query(models.User.height).all()

but it doesn't work.

I use MSSQL, if it's important.

Upvotes: 5

Views: 1748

Answers (1)

finswimmer
finswimmer

Reputation: 15162

Instead of using a dependency you can import the SessionLocal you've created as shown in the FastAPI manual and use a contextmanager to open and close this session:

@app.on_event("startup")
async def sample_test():
    with SessionLocal() as db:
        return db.query(models.User.height).all()

Upvotes: 4

Related Questions