How to setup nginx for a Flask app on a server with Plesk installed

2020-02-15 nginx flask config plesk

I want to deploy a little Flask webapp on a root cloud server with Plesk installed. I followed this tutorial as it uses Nginx and Gunicorn, like proposed by the developer of Flask: Miguel Grinberg.

The problem is that Plesk has a modified variant of nginx pre-installed named sw-nginx and I've absolutely no clue on how to implement that line of code:

server {
   listen 80;

    location / {
      include proxy_params;
      proxy_pass http://unix:/var/www/vhosts/;

If I just put in in a .conf file, the configtest of Nginx fails:

$ nginx -t
nginx: [emerg] open() "/etc/nginx/proxy_params" failed (2: No such file or directory) in /etc/nginx/conf.d/myproject.conf:6
nginx: configuration file /etc/nginx/nginx.conf test failed

Maybe the syntax of the proxy_pass value is wrong (I tried many, here I put one of them), or maybe the proxy_pass param isn't supported or has to be implemented somewhere else?

PS: I also found this answer How to deploy Flask project on Plesk subdomain But I read somewhere, that replacing sw-nginx by the standard nginx wouldn't be supported by Plesk. Don't want to break anything...

Thanks for your help.