CODEWITHSUNDEEP
sqlalchemy
NoPlaceLike127.0.0.1
NoPlaceLike127.0.0.1

Reputation: 451

SQLAlchemy 1.4 async event listeners

Trying to use event listeners(https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents ) on a async sqlalchemy engine and am getting this error: {NotImplementedError}asynchronous events are not implemented at this time. Apply synchronous listeners to the AsyncEngine.sync_engine or AsyncConnection.sync_connection attributes.

If I'm understanding this correctly I cant use events on an async engine and I have to switch to a sync engine if I want event support?

engine: Engine = create_async_engine(
    URL, echo=True, future=True
)

async_session = sessionmaker(
    engine, class_=AsyncSession, expire_on_commit=False, future=True
)


event.listens_for(engine, "do_connect")(do_connect_listener)
event.listens_for(engine, "engine_connect")(engine_connect_listener)

Upvotes: 6

Views: 5012

Answers (1)

NoPlaceLike127.0.0.1
NoPlaceLike127.0.0.1

Reputation: 451

got an answer from the SQLAlchemy discussion section on github. All credit to the OP(https://github.com/sqlalchemy/sqlalchemy/discussions/6594#discussioncomment-836437):

"Hi,

As suggested by the exception you may use the sync_engine/sync_connection when applying events. Here is an example:"



import asyncio
from sqlalchemy import event
from sqlalchemy.ext.asyncio import create_async_engine

engine = create_async_engine("sqlite+aiosqlite:///:memory:")

@event.listens_for(engine.sync_engine, "do_connect")
def do_connect(dialect, conn_rec, cargs, cparams):
    print("some-function")

@event.listens_for(engine.sync_engine, "engine_connect")
def engine_connect(conn, branch):
    print("engine_connect", conn.exec_driver_sql("select 1").scalar())

async def go():
    async with engine.connect() as conn:
        res = await conn.exec_driver_sql("select 2")
        print("go", res.scalar())

asyncio.run(go())

Upvotes: 9

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