0

I am using SQLAlchemy and mysql-connector. While executing a query, if I get mysql.connector.errors.DatabaseError I have used the exception provided by mysql.

The exception is going in the Exception block and not in the DatabaseError catch block.

Code

try:
    row_exists = None
    session_object = self.connect_to_database()
    # check if the value exists or not
    try:
        if session_object.query(
                exists().where(
                    ConnectorRequest.CR_Context_Key == input_context['Context_Key'])).scalar():
            row_exists = True
        else:
            row_exists = False
    except DatabaseError as mysql_error:
        logger.error('Error connecting to the MYSQL Server.Invalid database IP or Port provided' +
                     f'\nError-{str(mysql_error)}', exc_info=True)
    # close the session_object
    session_object.close()
    return row_exists
except Exception as error:
    logger.error('Error in exists query of the database' +
                 f'\nException - {str(error)}', exc_info=True)
  • Error caught in Exception
(mysql.connector.errors.DatabaseError) 2003 (HY000): Can't connect to MySQL server on '10.10.1.00:3306' (101)
(Background on this error at: https://sqlalche.me/e/14/4xp6)
  • Stacktrace
{"asctime": "2023-02-01 13:53:45,195", "levelname": "ERROR", "module": "Helper", "funcName": "check_if_file_is_already_processed", "process": 22216, 
"message": "Error in exists query of the database\nException - (mysql.connector.errors.DatabaseError) 2003 (HY000): Can't connect to MySQL server on '10.10.1.00:3306' (101)\n(Background on this error at: https://sqlalche.me/e/14/4xp6)", 
"exc_info": "Traceback (most recent call last):\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/connection_cext.py\", line 232, in _open_connection\n    self._cmysql.connect(**cnx_kwargs)\n_mysql_connector.MySQLInterfaceError: Can't connect to MySQL server on '10.10.1.00:3306' (101)\n\nDuring handling of the above exception, another exception occurred:\n\nTraceback (most recent call last):\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py\", line 3361, in _wrap_pool_connect\n    return fn()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 327, in connect\n    return _ConnectionFairy._checkout(self)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 894, in _checkout\n    fairy = _ConnectionRecord.checkout(pool)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 493, in checkout\n    rec = pool._do_get()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/impl.py\", line 146, in _do_get\n    self._dec_overflow()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/langhelpers.py\", line 72, in __exit__\n    with_traceback=exc_tb,\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py\", line 211, in raise_\n    raise exception\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/impl.py\", line 143, in _do_get\n    return self._create_connection()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 273, in _create_connection\n    return _ConnectionRecord(self)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 388, in __init__\n    self.__connect()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 691, in __connect\n    pool.logger.debug(\"Error on connect(): %s\", e)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/langhelpers.py\", line 72, in __exit__\n    with_traceback=exc_tb,\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py\", line 211, in raise_\n    raise exception\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 686, in __connect\n    self.dbapi_connection = connection = pool._invoke_creator(self)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/create.py\", line 578, in connect\n    return dialect.connect(*cargs, **cparams)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/default.py\", line 598, in connect\n    return self.dbapi.connect(*cargs, **cparams)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/__init__.py\", line 272, in connect\n    return CMySQLConnection(*args, **kwargs)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/connection_cext.py\", line 85, in __init__\n    self.connect(**kwargs)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/abstracts.py\", line 1003, in connect\n    self._open_connection()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/connection_cext.py\", line 235, in _open_connection\n    sqlstate=exc.sqlstate)\nmysql.connector.errors.DatabaseError: 2003 (HY000): Can't connect to MySQL server on '10.10.1.00:3306' (101)\n\nThe above exception was the direct cause of the following exception:\n\nTraceback (most recent call last):\n  File \"/home/usr/Workarea-2/usr/pycharm_project/toyota_finance_service/python_module/folder_listener_connector/folder_listener_connector/Helper.py\", line 155, in check_if_file_is_already_processed\n    ConnectorRequest.CR_Context_Key == input_context['Connector_Context_Key'])).scalar():\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py\", line 2893, in scalar\n    ret = self.one()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py\", line 2870, in one\n    return self._iter().one()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py\", line 2919, in _iter\n    execution_options={\"_sa_orm_load_options\": self.load_options},\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/orm/session.py\", line 1713, in execute\n    conn = self._connection_for_bind(bind)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/orm/session.py\", line 1553, in _connection_for_bind\n    engine, execution_options\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/orm/session.py\", line 747, in _connection_for_bind\n    conn = bind.connect()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py\", line 3315, in connect\n    return self._connection_cls(self, close_with_result=close_with_result)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py\", line 96, in __init__\n    else engine.raw_connection()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py\", line 3394, in raw_connection\n    return self._wrap_pool_connect(self.pool.connect, _connection)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py\", line 3365, in _wrap_pool_connect\n    e, dialect, self\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py\", line 2199, in _handle_dbapi_exception_noconnection\n    sqlalchemy_exception, with_traceback=exc_info[2], from_=e\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py\", line 211, in raise_\n    raise exception\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py\", line 3361, in _wrap_pool_connect\n    return fn()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 327, in connect\n    return _ConnectionFairy._checkout(self)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 894, in _checkout\n    fairy = _ConnectionRecord.checkout(pool)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 493, in checkout\n    rec = pool._do_get()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/impl.py\", line 146, in _do_get\n    self._dec_overflow()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/langhelpers.py\", line 72, in __exit__\n    with_traceback=exc_tb,\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py\", line 211, in raise_\n    raise exception\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/impl.py\", line 143, in _do_get\n    return self._create_connection()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 273, in _create_connection\n    return _ConnectionRecord(self)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 388, in __init__\n    self.__connect()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 691, in __connect\n    pool.logger.debug(\"Error on connect(): %s\", e)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/langhelpers.py\", line 72, in __exit__\n    with_traceback=exc_tb,\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py\", line 211, in raise_\n    raise exception\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/pool/base.py\", line 686, in __connect\n    self.dbapi_connection = connection = pool._invoke_creator(self)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/create.py\", line 578, in connect\n    return dialect.connect(*cargs, **cparams)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/sqlalchemy/engine/default.py\", line 598, in connect\n    return self.dbapi.connect(*cargs, **cparams)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/__init__.py\", line 272, in connect\n    return CMySQLConnection(*args, **kwargs)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/connection_cext.py\", line 85, in __init__\n    self.connect(**kwargs)\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/abstracts.py\", line 1003, in connect\n    self._open_connection()\n  File \"/home/usr/Workarea-2/usr/python_proj_env/folder_listener_connector_venv/lib/python3.6/site-packages/mysql/connector/connection_cext.py\", line 235, in _open_connection\n    sqlstate=exc.sqlstate)\nsqlalchemy.exc.DatabaseError: (mysql.connector.errors.DatabaseError) 2003 (HY000): Can't connect to MySQL server on '10.10.1.00:3306' (101)\n(Background on this error at: https://sqlalche.me/e/14/4xp6)"}
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  • 1
    Can you edit and share the full stacktrace ? I guess self.connect_to_database throw the error, and this line IS NOT in the try/except block of DatabaseError Commented Feb 1, 2023 at 8:11
  • In fact you need to swap your exception handling regarding the messages of your logger. the inner one should handle "error in query" and the outer one the connection error Commented Feb 1, 2023 at 8:12
  • @azro i have added the function self.connect_to_database in the question. Also, the error is not being raised by that function. Is it because I am making use of mysql-connector-python and sqlalchemy both? Commented Feb 1, 2023 at 8:14
  • @azro also, if i move the except block outside still the error is not being caught. Commented Feb 1, 2023 at 8:15
  • You don't have added anything. edit and add the full stacktrace please Commented Feb 1, 2023 at 8:17

1 Answer 1

Reset to default
1

The exception is sqlalchemy.exc.DatabaseError; SQLAlchemy wraps the error from the DB-API connector (here MySQL-Connector) but displays the details from it.

So you need to do

from sqlalchemy.exc import DatabaseError

...

try:
    # something
except DatabaseError:
    # handle exception
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2 Comments

In the post it written in the stacktrace that the error is a "mysql.connector.errors.DatabaseError" so ?
@azro the OP is using SQLAlchemy - note the "(Background on this error at: sqlalche.me/e/14/4xp6)" in the error message. SQLA traps the DB-API error in an SQLA exception and raises that, but exposes the original error mesages.

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