is it possible to run something on resource cleanup? For instance, we are trying to track database connections in order to properly manage load against a group of databases. When we're finished with the resource, we'd like to decrement a counter in a central database

this doesn’t exist right now, but is something we’re looking into. Not 100% sure if this will meet your requirements, but could you use a context manager within the resource? For example, in the duckdb io manager (basically just a resource) we have a function that is a context manager and does some cleanup when the context is closed https://github.com/dagster-io/dagster/blob/master/python_modules/libraries/dagster-duckdb/dagster_duckdb/io_manager.py#L132 in using this you would do something like

with duckdb_resource.connect() as con:
    # do stuff

# do more stuff outside the with statement

and then after the

with

bock is exited, the section of the

connect

function after the

yield

is executed

interesting, so I would define the resource as a class that has this

connect

method and that yields my actual database connection, and then after the yield, do my cleanup work? That would probably work for our usecase

You should be able to have the factory be the context manager and get rid of the nested function

thank you!

you could put a try finally in your context manager and then the finally will always be run, even if there’s a failure

@contextmanager
def managed_resource(*args, **kwds):
    # Code to acquire resource, e.g.:
    resource = acquire_resource(*args, **kwds)
    try:
        yield resource
    finally:
        # Code to release resource, e.g.:
        release_resource(resource)

some helpful docs https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager

thanks!