Added Documentation for usage with async tools. Fixes #626

[deshetti]

I have spent a good amount of time to figure out async implementation with SQLModel & FastAPI in one of our projects and thought this would be a helpful guide for anyone who is looking to do the same in their projects.

A simple working project is available here to test. Running the docker-compose will start the postgres with the required database: https://github.com/deshetti/sqlmodel-async-example

[github-actions]

📝 Docs preview for commit a5fe1d1 at: https://ececea1e.sqlmodel.pages.dev

[github-actions]

📝 Docs preview for commit b0081f5 at: https://049f644f.sqlmodel.pages.dev

[peidrao]

Suggested change

	```
	```python

[peidrao]

Suggested change

	```
	pip install sqlmodel asyncpg fastapi uvicorn
	```
	```bash
	pip install sqlmodel asyncpg fastapi uvicorn

[alejandroperezlopez]

Suggested change

	# Ayschronous Context manager for handling database sessions
	# Asynchronous Context manager for handling database sessions

[StashOfCode]

@tiangolo , are you merging this in this century or next?

[moralespanitz]

@tiangolo Why don't you add the contribution?

[vduseev]

Interesting approach. Why not use async_sessionmaker?

[Lexachoc]

The async session part doesn't work for me and gives an error when executing statement.

https://github.com/deshetti/sqlmodel-async-example/blob/e412da00f557a352ee3f66a8545ef11401ea5dde/main.py#L42-L47

# Ayschronous Context manager for handling database sessions
@asynccontextmanager
async def get_session() -> AsyncSession:
    async_session = sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
    async with async_session() as session:
        yield session

error occurs at:
results= await session.exec(statement)

within an endpoint where the session is a dependency: session: AsyncSession = Depends(get_session)

error message: '_AsyncGeneratorContextManager' object has no attribute 'exec'

Also, there is a warning in Pycharm that says:
Unexpected type(s): (Any, Type[AsyncSession], bool) Possible type(s): (Connection | Connection | Engine | Engine | None, None, bool) (Connection | Connection | Engine | Engine | AsyncConnection | AsyncConnection | AsyncEngine | AsyncEngine | None, Type[_TSessionMakerType], bool) (Connection | Connection | Engine | Engine | None, None, bool) (Connection | Connection | Engine | Engine | None, Type[_TSessionMakerType], bool)
for the sessionmaker

To overcome this, I use directly the AsyncSession instead of sessionmaker:

async def get_session() -> AsyncSession:
    async with AsyncSession(data_engine) as session:
        yield session

which works for me when using the async session as dependencies.

Hope this helps others or do you have an idea why the original solution doesn't work?

This seems to be the reason for the error or is related to it: fastapi/fastapi#9054 (comment)

version:
FastAPI: 0.111.0
sqlmodel: 0.0.19
But this already happens with older versions, even if I use the latest version.

[thomasborgen]

.dict() is deprecated for model_dump()

Suggested change

	db_user = User(**user.dict())
	db_user = User(**user.model_dump())

[thomasborgen]

.dict() is deprecated for model_dump()

Suggested change

	db_user = User(**user.dict())
	db_user = User(**user.model_dump())

[thomasborgen]

Maybe drop the create_user() function and just have everything in here. We also get the added benefit of showing of dependency injection, we are in the advanced section after all.

Suggested change

	@app.post("/users/", response_model=User)
	async def create_user_endpoint(user: UserCreate):
	db_user = User(**user.dict())
	result = await create_user(db_user)
	return result
	@app.post("/users/", response_model=User)
	async def create_user_endpoint(
	user: UserCreate,
	session: AsyncSession = Depends(get_session),
	):
	db_user = User(user.model_dump())
	session.add(db_user)
	await session.commit()
	await session.refresh(db_user)
	return db_user

[zuoc1993]

When will this be released?

[grimzy]

Can use

sqlmodel/sqlmodel/ext/asyncio/session.py

Line 32 in 0c65fed

class AsyncSession(_AsyncSession):

instead of SQLAlchemy's

[github-actions]

This pull request has a merge conflict that needs to be resolved.

[svlandeg]

Hi @deshetti, all,

Thanks for the contribution 🙏

We've discussed this internally and decided that we prefer to write the first draft of this new documentation section ourselves. We are now tracking this on our internal TODO list. We'll go ahead and close this one in the meantime.