Method checkout

lib/sqlalchemy/pool/base.py:708–741

(cls, pool: Pool)

    @classmethod
    def checkout(cls, pool: Pool) -> _ConnectionFairy:
        if TYPE_CHECKING:
            rec = cast(_ConnectionRecord, pool._do_get())
        else:
            rec = pool._do_get()

        try:
            dbapi_connection = rec.get_connection()
        except BaseException as err:
            with util.safe_reraise():
                rec._checkin_failed(err, _fairy_was_created=False)

            # not reached, for code linters only
            raise

        echo = pool._should_log_debug()
        fairy = _ConnectionFairy(pool, dbapi_connection, rec, echo)

        rec.fairy_ref = ref = weakref.ref(
            fairy,
            lambda ref: (
                _finalize_fairy(
                    None, rec, pool, ref, echo, transaction_was_reset=False
                )
                if _finalize_fairy is not None
                else None
            ),
        )
        _strong_ref_connection_records[ref] = rec
        if echo:
            pool.logger.debug(
                "Connection %r checked out from pool", dbapi_connection
            )
        return fairy

    def _checkin_failed(
        self, err: BaseException, _fairy_was_created: bool = True