Permission denied coming for nonroot user from pod while writing content on GCS bucket

[swastik_nayak]

I have a docker image where write operation is being done by 4 nonroot users 
mongodb,postgres,cavisson.netstorm. 
I am using pv, pvc, statefulstate for deploying this into gcs bucket. 

In pv i have mentioned 
options: "-o allow_other --file-mode=0777 --dir-mode=0777"

GCS bucket is also public to internet. Still i am unable to write anything to it. 
Also i am unable to change permissions of the directory to specific username. 
I can't use UID GID in pv as it is not contstant throughout the docker image tags