Calling a stored procedure via aiomysql.sa?

[sjlongland]

How does one execute a stored procedure through the classes provided by aiomysql.sa? I need to use a stored procedure for a couple of operations, with all others being done via direct queries to tables/views. The real SQLAlchemy Engine object has a raw_connection method for doing this, but I do not see an equivalent in aiomysql.sa.Engine.

[sjlongland]

Well, a dodgy hack around this… it seems I can get at the underlying Connection from a SAConnection by abusing the fact that it stores it as a "private" attribute called _connection.

    @coroutine
    def create(self, records, permit_fields=None,
            forbid_fields=None, conn=None):
        """
        Create the given events.  This overrides the default _create
        method and uses the CreateNewEvent stored procedure.
        """
        # Enforce conn == None
        if conn is not None:
            raise ValueError('Event creation requires its own connection')

        with (yield from self._db.connection) as conn:
            # !!! XXX DODGY HACK ALERT XXX !!!
            # See https://github.com/aio-libs/aiomysql/issues/430
            raw_conn = conn._connection
            cur = yield from raw_conn.cursor()
            single = False
            if not isinstance(records, list):
                single = True
                records = [records]

            # Start the transaction
            yield from raw_conn.begin()
            try:
                events = []

                for record in records:
                    # Create the given event
                    config = record.get('EventConfig')
                    if config:
                        config = json.dumps(config)

                    yield from cur.callproc(
                            'CreateNewEvent',
                            [
                                record['EventType'],
                                record['EventName'],
                                datetime.dt_to_tz(record['StartDate']),
                                datetime.dt_to_tz(record['EndDate']),
                                record['EventAuthorizingOrganisation'],
                                record['EventLocation'],
                                config
                            ]
                    )

                    # Look for current event
                    yield from cur.execute('SELECT EventID FROM currentevent;')
                    (event_id,) = yield from cur.fetchone()
                    events.append({
                        'id': event_id,
                        'data': record
                    })

                # All done
                yield from raw_conn.commit()

                if single:
                    return events[0]
                else:
                    return events
            except:
                yield from raw_conn.rollback()
                raise

It would be far nicer to have a raw_connection method like the core SQLAlchemy library provides.