[jira] [Resolved] (AIRFLOW-27) MsSqlOperator: ERROR - 'pymssql.Connection' object attribute 'autocommit' is read-only

["Chris Riccomini (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AIRFLOW-27?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Chris Riccomini resolved AIRFLOW-27.
------------------------------------
    Resolution: Fixed

> MsSqlOperator:  ERROR - 'pymssql.Connection' object attribute 'autocommit' is read-only
> ---------------------------------------------------------------------------------------
>
>                 Key: AIRFLOW-27
>                 URL: https://issues.apache.org/jira/browse/AIRFLOW-27
>             Project: Apache Airflow
>          Issue Type: Bug
>         Environment: Ubuntu 14.04.4 LTS
>            Reporter: Gabriel Llobera
>            Assignee: Gabriel Llobera
>              Labels: newbie
>   Original Estimate: 0.5h
>  Remaining Estimate: 0.5h
>
> I have the following code:
> {code}
> from airflow import DAG
> from airflow.operators import MsSqlOperator
> from datetime import datetime, timedelta
> args = {
>     'owner': 'airflow',
>     'depends_on_past': True,
>     'start_date': datetime(2016, 4, 6, 1, 0),
>     'email': ['example@email.com'],
>     'email_on_failure': True,
>     'email_on_retry': True,
>     'retries': 1,
>     'retry_delay': timedelta(minutes=5),
>     'execution_timeout': timedelta(hours=23),
>     'priority_weight': 10
> }
> dag = DAG('dag_name', default_args=args, schedule_interval='0 1 * * *')
> t_generate_metadata_csv = MsSqlOperator(task_id='task_id',
>                                         sql='SELECT a FROM b',
>                                         mssql_conn_id='mssql_conn',
>                                         dag=dag)
> {code}
> And I'm getting this error:
> {code}
> ERROR - 'pymssql.Connection' object attribute 'autocommit' is read-only
> Traceback (most recent call last):
>   File "/usr/local/lib/python2.7/dist-packages/airflow/models.py", line 1064, in run
>     result = task_copy.execute(context=context)
>   File "/usr/local/lib/python2.7/dist-packages/airflow/operators/mssql_operator.py", line 34, in execute
>     hook.run(self.sql, parameters=self.parameters)
>   File "/usr/local/lib/python2.7/dist-packages/airflow/hooks/dbapi_hook.py", line 101, in run
>     self.set_autocommit(conn, autocommit)
>   File "/usr/local/lib/python2.7/dist-packages/airflow/hooks/dbapi_hook.py", line 115, in set_autocommit
>     conn.autocommit = autocommit
> {code}
> Looking at the source code I think I might know why it fails (I have added links to the referenced lines in the source code). In dbapi_hook, [if the connection supports autocommit|https://github.com/airbnb/airflow/blob/master/airflow/hooks/dbapi_hook.py#L123] then we call set_autocommit, which does [conn.autocommit = autocommit|https://github.com/airbnb/airflow/blob/master/airflow/hooks/dbapi_hook.py#L138].
> MsSqlHook has [supports_autocommit set to true|https://github.com/airbnb/airflow/blob/master/airflow/hooks/mssql_hook.py#L13], but the connection type it uses, which is pymssql has no autocommit attribute. [Instead it is called _autocommit|https://github.com/pymssql/pymssql/blob/f814fd9dedc7cd87fabbe92dfb1b6d19a5ed31a3/src/pymssql.pyx#L209] and [autocommit is defined as a function|https://github.com/pymssql/pymssql/blob/f814fd9dedc7cd87fabbe92dfb1b6d19a5ed31a3/src/pymssql.pyx#L255] to turn autocommit on or off.
> So it seems that the error is caused by trying to set the conn.autocommit to a boolean value when it is not actually a variable but a function. This seems to be supported by this [link|http://www.gossamer-threads.com/lists/python/python/514536] where someone causes the same error by trying to assign a value to a function.



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