Getting 'Cannot use MongoClient' exception when refreshing django API request - django

Question

I currently have an AWS EC2 instance running that is running a web server using Apache (httpd) to deploy the server in the instance. The project uses the Django, Djongo, and Django Rest Framework python libraries. It works initially as it gives back an API response via JSON. However, when making another API call, it comes out with the following exception:
DatabaseError at /profile/7/
No exception message supplied
Environment:
Request Method: GET
Request URL: https://[redacted]/profile/7/?format=json
Django Version: 3.2.16
Python Version: 3.7.10
Installed Applications:
['django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'rest_framework',
'api']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware']
Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/djongo/sql2mongo/query.py", line 808, in __iter__
yield from iter(self._query)
File "/usr/local/lib/python3.7/site-packages/djongo/sql2mongo/query.py", line 166, in __iter__
for doc in cursor:
File "/usr/local/lib64/python3.7/site-packages/pymongo/cursor.py", line 1248, in next
if len(self.__data) or self._refresh():
File "/usr/local/lib64/python3.7/site-packages/pymongo/cursor.py", line 1165, in _refresh
self.__send_message(q)
File "/usr/local/lib64/python3.7/site-packages/pymongo/cursor.py", line 1053, in __send_message
operation, self._unpack_response, address=self.__address
File "/usr/local/lib64/python3.7/site-packages/pymongo/_csot.py", line 105, in csot_wrapper
return func(self, *args, **kwargs)
File "/usr/local/lib64/python3.7/site-packages/pymongo/mongo_client.py", line 1335, in _run_operation
retryable=isinstance(operation, message._Query),
File "/usr/local/lib64/python3.7/site-packages/pymongo/_csot.py", line 105, in csot_wrapper
return func(self, *args, **kwargs)
File "/usr/local/lib64/python3.7/site-packages/pymongo/mongo_client.py", line 1441, in _retryable_read
server = self._select_server(read_pref, session, address=address)
File "/usr/local/lib64/python3.7/site-packages/pymongo/mongo_client.py", line 1247, in _select_server
topology = self._get_topology()
File "/usr/local/lib64/python3.7/site-packages/pymongo/mongo_client.py", line 1203, in _get_topology
self._topology.open()
File "/usr/local/lib64/python3.7/site-packages/pymongo/topology.py", line 192, in open
self._ensure_opened()
File "/usr/local/lib64/python3.7/site-packages/pymongo/topology.py", line 592, in _ensure_opened
raise InvalidOperation("Cannot use MongoClient after close")
The above exception (Cannot use MongoClient after close) was the direct cause of the following exception:
File "/usr/local/lib/python3.7/site-packages/djongo/cursor.py", line 65, in fetchmany
ret.append(self.result.next())
File "/usr/local/lib/python3.7/site-packages/djongo/sql2mongo/query.py", line 797, in __next__
result = next(self._result_generator)
File "/usr/local/lib/python3.7/site-packages/djongo/sql2mongo/query.py", line 830, in __iter__
raise exe from e
The above exception (
Keyword: FAILED SQL: SELECT "api_account"."userID", "api_account"."phoneNum", "api_account"."displayName", "api_account"."seeking", "api_account"."birthday", "api_account"."motto", "api_account"."faithID", "api_account"."job", "api_account"."hobbies", "api_account"."politicsID", "api_account"."city", "api_account"."stateID", "api_account"."bio", "api_account"."facePlot" FROM "api_account" WHERE "api_account"."userID" = %(0)s LIMIT 21
Params: (7,)
Version: 1.3.6
Sub SQL: None
FAILED SQL: None
Params: None
Version: None) was the direct cause of the following exception:
File "/usr/local/lib/python3.7/site-packages/django/db/utils.py", line 97, in inner
return func(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/djongo/cursor.py", line 70, in fetchmany
raise db_exe from e
The above exception () was the direct cause of the following exception:
File "/usr/local/lib/python3.7/site-packages/django/core/handlers/exception.py", line 47, in inner
response = get_response(request)
File "/usr/local/lib/python3.7/site-packages/django/core/handlers/base.py", line 181, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/usr/local/lib/python3.7/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
return view_func(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/django/views/generic/base.py", line 70, in view
return self.dispatch(request, *args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/rest_framework/views.py", line 509, in dispatch
response = self.handle_exception(exc)
File "/usr/local/lib/python3.7/site-packages/rest_framework/views.py", line 469, in handle_exception
self.raise_uncaught_exception(exc)
File "/usr/local/lib/python3.7/site-packages/rest_framework/views.py", line 480, in raise_uncaught_exception
raise exc
File "/usr/local/lib/python3.7/site-packages/rest_framework/views.py", line 506, in dispatch
response = handler(request, *args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/rest_framework/generics.py", line 282, in get
return self.retrieve(request, *args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/rest_framework/mixins.py", line 54, in retrieve
instance = self.get_object()
File "/usr/local/lib/python3.7/site-packages/rest_framework/generics.py", line 96, in get_object
obj = get_object_or_404(queryset, **filter_kwargs)
File "/usr/local/lib/python3.7/site-packages/rest_framework/generics.py", line 19, in get_object_or_404
return _get_object_or_404(queryset, *filter_args, **filter_kwargs)
File "/usr/local/lib/python3.7/site-packages/django/shortcuts.py", line 76, in get_object_or_404
return queryset.get(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 431, in get
num = len(clone)
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 262, in __len__
self._fetch_all()
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 1324, in _fetch_all
self._result_cache = list(self._iterable_class(self))
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 51, in __iter__
results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
File "/usr/local/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1208, in execute_sql
return list(result)
File "/usr/local/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1646, in cursor_iter
for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
File "/usr/local/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1646, in <lambda>
for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
File "/usr/local/lib/python3.7/site-packages/django/db/utils.py", line 97, in inner
return func(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/django/db/utils.py", line 90, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "/usr/local/lib/python3.7/site-packages/django/db/utils.py", line 97, in inner
return func(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/djongo/cursor.py", line 70, in fetchmany
raise db_exe from e
Exception Type: DatabaseError at /profile/7/
Exception Value:
It starts working at one point, but then gives the exception a few other times. I could gleam that the exception actually is 'Cannot use MongoClient after close.' However, I'm not sure what exactly would be causing this as I haven't modified any other code to the underlying workings of Django. What would be causing this?
Versions of the python libraries:
Django 3.2.16
djangorestframework 3.14.0
djongo 1.3.6
pymongo 4.3.2
sqlparse 0.2.4

Answer 1

Finally found out what the issue was. Turns out the version of Pymongo installed with the rest of the libraries was causing the issue. Here is the combination of library versions that seem to work best with eachother:
Django 4.1.2
Pymongo 3.12.1
DjangoRestFramework 3.14.0
Hopefully this saves someone else time. In my instance, ensuring I had Python 3.8 installed helped as well.