nginx.conf.rb

daemon off;
# Heroku dynos have at least 4 cores.
worker_processes <%= ENV['NGINX_WORKERS'] || 4 %>;

events {
	use epoll;
	accept_mutex on;
	worker_connections 1024;
}



http {
        gzip on;
        gzip_comp_level 2;
        gzip_min_length 512;

	server_tokens off;

	log_format l2met 'measure#nginx.service=$request_time request_id=$http_x_request_id';
	access_log logs/nginx/access.log l2met;
	error_log logs/nginx/error.log;

	include mime.types;
	default_type application/octet-stream;
	sendfile on;

	# Must read the body in 5 seconds.
	client_body_timeout 5;

	upstream app_server {
		server unix:/tmp/nginx.socket fail_timeout=0;
  }

  # CloudFlare
  # https://support.cloudflare.com/hc/en-us/articles/200170706-How-do-I-restore-original-visitor-IP-with-Nginx-
  # https://www.cloudflare.com/ips/
  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 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 2405:8100::/32;
  set_real_ip_from 2405:b500::/32;
  set_real_ip_from 2606:4700::/32;
  set_real_ip_from 2803:f800::/32;
  real_ip_header CF-Connecting-IP;

	server {
		listen <%= ENV["PORT"] %>;
		server_name _;
		keepalive_timeout 5;

		location / {
      proxy_set_header X-Real-IP $remote_addr;
			proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
			proxy_set_header Host $http_host;
			proxy_redirect off;
			proxy_pass http://app_server;
		}
	}


}