Nginx configuration for hosting multiple instances of ASF

nginx.conf

http {
  	map $request_uri $instance_port {
		default     0;
		"~*^/0"     1240;
		"~*^/1"     1242;
		"~*^/2"     1243;
		"~*^/3"     1244;
		"~*^/4"     1235;
		"~*^/5"     1234;
		"~*^/6"     1233;
		"~*^/7"     1232;
		"~*^/8"     1231;
		"~*^/9"     1337;
	}
	
	server {
		listen 80;
		listen [::]:80;
		server_name *.example.com;
		# enforce https
		return 301 https://$host$request_uri;
	}

	server {
		listen 443 ssl;
		server_name	example.com;
		ssl_certificate	/etc/letsencrypt/live/example.com/fullchain.pem;
		ssl_certificate_key	/etc/letsencrypt/live/example.com/privkey.pem;
		error_page 497	https://$host:$server_port$request_uri;
		
		proxy_read_timeout 30m;
		proxy_set_header Host asf.example.com;
		proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
		proxy_set_header X-Forwarded-Host $host:$server_port;
		proxy_set_header X-Forwarded-Proto $scheme;
		proxy_set_header X-Forwarded-Server $host;
		proxy_set_header X-Real-IP $remote_addr;

		location ~* /Api/NLog {
			proxy_pass http://127.0.0.1:$instance_port;

			proxy_http_version 1.1;
			proxy_set_header Connection "Upgrade";
			proxy_set_header Upgrade $http_upgrade;
		}

		location / {
			proxy_pass http://127.0.0.1:$instance_port;
		}
	}
}