In an update to my previous post about Isso a recent change by the maintainers of the Debian Isso package means we need to make a small change to the nginx configuration. It seems like instead of presenting a TCP port (even if that port is different from the one in the official documentation) they’ve decided to set up a UNIX socket with SystemD to handle communication with the service. A handy enough change and nice from a security perspective, but a little bothersome when you reboot the service and start getting 502 gateway errors for all of your comments. You can find the definition for this socket at /lib/systemd/system/isso.socket at time of writing, and (currently) it creates the socket as /run/isso.sock. This fits nicely into our existing nginx configuration as shown below:

# /usr/nginx/sites-available/
# ...
location / {
  # Replace this line ->
  # proxy_pass;
  # With this line ->
  proxy_pass http://unix:/run/isso.sock:/;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_set_header Host $host;
  proxy_set_header X-Forwarded-Proto $scheme;

With that done, we can restart nginx and be back on our way!

$ sudo systemctl restart nginx