Getting “not all arguments converted during string formatting” exception in AWS Lambda function

I am trying to write an AWS Lambda function in python that retrieves records from a table. I have no trouble running the code locally. However, when I run the code in AWS Lambda function, I get the error “not all arguments converted during string formatting”.

The query is executed by the following code:

class SalesReceipt(declarative_base(), PersistentBase.PersistentBase): tablename = ‘sales_receipts’

id = Column(BigInteger, primary_key=True, autoincrement=True)
externalId = Column(String(35), nullable=False)
accountId = Column(BigInteger, nullable=False)
customerId = Column(BigInteger, nullable=False)
orderNumber = Column(String(30), nullable=True)
orderType = Column(String(35), nullable=True)
saleDate = Column(DateTime, nullable=False)
saleAmount = Column(BigInteger, nullable=False)
taxAmount = Column(BigInteger, nullable=False)
totalAmount = Column(BigInteger, nullable=False)


def get_by_account_id(self, account_id):
    logger = logging.getLogger()
    message = '=== [SalesReceipt]account_id = %d' % (account_id)
    logger.info(message)
    data_service = ds.DataService()
    try:
        session = data_service.get_session()
        query = session.query(SalesReceipt).filter(SalesReceipt.accountId == account_id)
        #query = session.query(SalesReceipt)
        logger.info('=== [SalesReceipt]Query created = %s' % (str(query)))
        result = query.all()
        logger.info('=== [SalesReceipt]Query has been successfully executed.')
        return result
    except NoResultFound:
        logging.error('=== [SalesReceipt]No results found')
        return None
    except Exception as ex:
        logging.error('=== [SalesReceipt]Failed to retrieve sales receipts for the account.', ex)
        raise
    except:
        logging.error('=== [SalesReceipt]Caught un-handled exception.')
        raise

The error is encountered during statement result = query.all(). Nothing is executed after that and none of my catch blocks are entered.

I have googled this statement but have not found any clue as to why this is happening inside sqlalchemy functions. I have verified that the query is correct by printing the query out and executing it against the database manually.

I am also a newbie to python so any help will be appreciated.

Answer

Most likely the issue is in the following line –

logging.error('=== [SalesReceipt]Failed to retrieve sales receipts for the account.', ex)

ex is passed but never included in the string. Try the following instead –

logging.error('=== [SalesReceipt]Failed to retrieve sales receipts for the account - %s' % ex)

or

logging.error('=== [SalesReceipt]Failed to retrieve sales receipts for the account.')