Nginx Rate Limiting With CloudFlare

I want to have a Rate Limiting code with the following options:

• I'm using CloudFlare, so I want it to look for the real IP address.
• I want to have a whitelist option
• I want to make a file with a list of the blocked IP addresses (IPs who reached the threshold).
• The rate limiting will be 15 requests per 2 seconds, something like that.

I found this answer:
https://serverfault.com/a/642357

And it looks great, but will it look for the real IP address? I have this code:

set_real_ip_from 103.21.244.0/22;
set_real_ip_from 103.22.200.0/22;
set_real_ip_from 103.31.4.0/22;
set_real_ip_from 104.16.0.0/12;
set_real_ip_from 108.162.192.0/18;
set_real_ip_from 131.0.72.0/22;
set_real_ip_from 141.101.64.0/18;
set_real_ip_from 162.158.0.0/15;
set_real_ip_from 172.64.0.0/13;
set_real_ip_from 173.245.48.0/20;
set_real_ip_from 188.114.96.0/20;
set_real_ip_from 190.93.240.0/20;
set_real_ip_from 197.234.240.0/22;
set_real_ip_from 198.41.128.0/17;
set_real_ip_from 199.27.128.0/21;
set_real_ip_from 2400:cb00::/32;
set_real_ip_from 2606:4700::/32;
set_real_ip_from 2803:f800::/32;
set_real_ip_from 2405:b500::/32;
set_real_ip_from 2405:8100::/32;

# use any of the following two
real_ip_header CF-Connecting-IP;
#real_ip_header X-Forwarded-For;

And also, how do I make this code listing the blocked IP addresses into a new file?