redis-py raises AttributeError - redis-py

Question

In what circumstances would redis-py raise the following AttributeError exception?
Isn't redis-py built by design to raise only redis.exceptions.RedisError based exceptions?
What would be a reasonable handling logic?
Traceback (most recent call last):
File "c:\Python27\Lib\threading.py", line 551, in __bootstrap_inner
self.run()
File "c:\Python27\Lib\threading.py", line 504, in run
self.__target(*self.__args, **self.__kwargs)
File C:\Users\Administrator\Documents\my_proj\my_module.py", line 33, in inner
ret = protected_func(*args, **kwargs)
File C:\Users\Administrator\Documents\my_proj\my_module.py", line 104, in _listen
for message in _pubsub.listen():
File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\client.py", line 1555, in listen
r = self.parse_response()
File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\client.py", line 1499, in parse_response
response = self.connection.read_response()
File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\connection.py", line 306, in read_response
response = self._parser.read_response()
File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\connection.py", line 104, in read_response
response = self.read()
File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\connection.py", line 89, in read
return self._fp.readline()[:-2]
AttributeError: 'NoneType' object has no attribute 'readline'

Answer 1

seems like an old question, but I faced the same problem recently.
My setup was using celery with redis as a broker. A ThreadPoolExecutor uses the shared celery object to batch tasks to workers. The batcher function waits for the submitted tasks to finish using celery.result.ResultSet.
After quick investigations, I found that celery somewhere uses a pub/sub mechanism to wait for the tasks to finish. And that is it, pub/sub don't play well with thread-safety per the official readme https://github.com/andymccurdy/redis-py#thread-safety
Honestly, I didn't try to prove my theory and fixed my problem by switching to a ProcessPoolExecutor instead.