In the Docker image, the app source is copied to /app/app/ (not
backend/app/), so parents[2] resolved to '/' instead of /app.
This left the fail2ban package absent from sys.path, causing every
pickle.loads() call on socket responses to raise:
ModuleNotFoundError: No module named 'fail2ban'
Replace the hardcoded parents[2] with a walk-up search that iterates
over all ancestors until it finds a fail2ban-master/ sibling directory.
Works correctly in both local dev and Docker without environment-specific
path magic.
Lukas
19bb94ee47