FileNotFoundError Python-Flask/Docker in Kubernetes Cluster

I am having problems with opening files in my Flask app, running in Docker container in a Kubernetes cluster.

Whenever I try to open a file i directory I am getting a FileNotFoundError. S3FS Object Storage is provisioned and the PersistentVolumeclaim is successfully mounted to my pod, so no issue there.

However, when trying to read a file from the mounted storage I get the said error. Here is how I read the file. The current_dir is /var/www

current_dir = os.path.dirname(__file__)
abs_path = os.path.join(current_dir, path)
with open(abs_path, "rb") as file:
    bin_data = file.read()

Additonally I have also tried all of the variants below, but none seem to work:

data_path = pathlib.Path('/var/www/uploads/')
abs_path = data_path / path_id

data_path = pathlib.Path('uploads/')
abs_path = data_path / path_id

abs_path = current_dir + '/uploads' + path_id

tmp = str('/uploads/' + path_id).split('/')
abs_path = os.path.join(os.path.dirname(__file__), *tmp)

The error I am getting is following:

[2020-04-02 18:16:49,359] ERROR in app: Exception on /internal/tusd [POST]
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1951, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python3.7/site-packages/flask_cors/extension.py", line 161, in wrapped_function
    return cors_after_request(app.make_response(f(*args, **kwargs)))
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1820, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/var/www/api_controller.py", line 95, in tusd_handler
    hexdigest = hash_file(str(upload_id), hash_type)
  File "/var/www/file_hasher.py", line 17, in hash_file
    with open(abs_path, "rb") as file:
FileNotFoundError: [Errno 2] No such file or directory: '/var/www/uploads/f7f1c686fbc40649879e8aee7f529c96'

However, when I exec -it into the container. The file, among others is present.

$ kubectl exec hasher-savoury-695669b858-nwg5j -- ls /var/www/uploads

f7f1c686fbc40649879e8aee7f529c96
f7f1c686fbc40649879e8aee7f529c96.info

Here is the Dockerfile I have been using. The commented fields are options I have tried out in order to get it working.

FROM python:3.7-alpine as base

ENV GROUP_ID=1000 \
    USER_ID=1000

RUN apk upgrade && apk update \
    && apk --no-cache add openssl-dev openssl
RUN apk --no-cache --update add --virtual build-dependencies gcc g++ make libffi-dev

RUN mkdir /var/www && mkdir /var/www/uploads
COPY . /var/www
WORKDIR /var/www

RUN pip install --upgrade pip && pip install -r requirements.txt && apk del build-dependencies
RUN pip install gunicorn

#RUN addgroup -g $GROUP_ID savoury
#RUN adduser -D -u $USER_ID -G savoury savoury -s /bin/sh \
#    && chown savoury:savoury -R var/www/

#USER savoury

EXPOSE 5080

ENTRYPOINT ["gunicorn"]
CMD ["-w", "4", "--bind", "0.0.0.0:5080", "wsgi"]

I have tried reading these files in Java an have succesfully read them. I have also tried to ´´´exec´´´ into the container and was able to perform this easily in the python console. I have no idea why the script above is not working.

Any help is greatly appreciated!