cassandra.cqlengine.CQLEngineException: Connection name '<object object at 0x7eff59dcc8e0>' doesn't exist in the registry.

Hi! I’m experiencing an issue where django-cassandra-engine stops working due to new Cython version not being compatible with cassandra-driver python package. I looked around the web a bit, and it suggests to me that Cython version needs to be 0.24.1, as Cython 0.25 breaks the cassandra-driver.

Thankfully, Datastax team released a new version of cassandra-driver: 3.7.1, and Cython issue is gone but now I’m having a new issue.

All I can speculate from your code and cassandra-driver codebase is that your connection.get_session() no longer works as cassandra-driver’s _connections dictionary is empty at the point of failure.

I spent the whole day to burn and crash therefore, any solution or advice would be really appreciated 😉

The below is the traceback from my Docker environment.

Thanks!!!

Traceback (most recent call last): File “/code/manage.py”, line 10, in <module> execute_from_command_line(sys.argv) File “/usr/local/lib/python2.7/site-packages/django/core/management/init.py”, line 353, in execute_from_command_line utility.execute() File “/usr/local/lib/python2.7/site-packages/django/core/management/init.py”, line 327, in execute django.setup() File “/usr/local/lib/python2.7/site-packages/django/init.py”, line 18, in setup apps.populate(settings.INSTALLED_APPS) File “/usr/local/lib/python2.7/site-packages/django/apps/registry.py”, line 108, in populate app_config.import_models(all_models) File “/usr/local/lib/python2.7/site-packages/django/apps/config.py”, line 202, in import_models self.models_module = import_module(models_module_name) File “/usr/local/lib/python2.7/importlib/init.py”, line 37, in import_module import(name) File “/usr/local/lib/python2.7/site-packages/django_cassandra_engine/models/init.py”, line 5, in <module> conn.connect() File “/usr/local/lib/python2.7/site-packages/django_cassandra_engine/base/init.py”, line 104, in connect self.connection = CassandraConnection(**settings) File “/usr/local/lib/python2.7/site-packages/django_cassandra_engine/connection.py”, line 58, in init self.setup() File “/usr/local/lib/python2.7/site-packages/django_cassandra_engine/connection.py”, line 62, in setup self.session = connection.get_session() File “/usr/local/lib/python2.7/site-packages/cassandra/cqlengine/connection.py”, line 293, in get_session conn = get_connection(connection) File “/usr/local/lib/python2.7/site-packages/cassandra/cqlengine/connection.py”, line 190, in get_connection raise CQLEngineException(“Connection name ‘{0}’ doesn’t exist in the registry.”.format(name)) cassandra.cqlengine.CQLEngineException: Connection name ‘<object object at 0x7eff59dcc8e0>’ doesn’t exist in the registry.

[bicepjai]

this is happening again with these versions. anyone faced this issue and resolved it ?

cassandra-driver==3.24.0
Django==2.2
django-cassandra-engine==1.6.1

when starting the all and trying to get queryset

app_container       | Traceback (most recent call last):
app_container       |   File "/usr/local/lib/python3.8/site-packages/django/core/handlers/exception.py", line 34, in inner
app_container       |     response = get_response(request)
app_container       |   File "/usr/local/lib/python3.8/site-packages/django/core/handlers/base.py", line 115, in _get_response
app_container       |     response = self.process_exception_by_middleware(e, request)
app_container       |   File "/usr/local/lib/python3.8/site-packages/django/core/handlers/base.py", line 113, in _get_response
app_container       |     response = wrapped_callback(request, *callback_args, **callback_kwargs)
app_container       |   File "/app/app/views.py", line 14, in query_view
app_container       |     test_text = str(list(Storage_Keys_DCDF_GB.objects.all()))
app_container       |   File "/usr/local/lib/python3.8/site-packages/cassandra/cqlengine/query.py", line 437, in __len__
app_container       |     self._execute_query()
app_container       |   File "/usr/local/lib/python3.8/site-packages/cassandra/cqlengine/query.py", line 472, in _execute_query
app_container       |     self._result_generator = (i for i in self._execute(self._select_query()))
app_container       |   File "/usr/local/lib/python3.8/site-packages/cassandra/cqlengine/query.py", line 404, in _execute
app_container       |     result = _execute_statement(self.model, statement, self._consistency, self._timeout, connection=connection)
app_container       |   File "/usr/local/lib/python3.8/site-packages/cassandra/cqlengine/query.py", line 1531, in _execute_statement
app_container       |     return conn.execute(s, params, timeout=timeout, connection=connection)
app_container       |   File "/usr/local/lib/python3.8/site-packages/cassandra/cqlengine/connection.py", line 331, in execute
app_container       |     conn = get_connection(connection)
app_container       |   File "/usr/local/lib/python3.8/site-packages/cassandra/cqlengine/connection.py", line 241, in get_connection
app_container       |     raise CQLEngineException("Connection name '{0}' doesn't exist in the registry.".format(name))
app_container       | cassandra.cqlengine.CQLEngineException: Connection name '<object object at 0x7f88d52eaed0>' doesn't exist in the registry.

[piecubed]

Im also having this issue on python3.8