Add option to configure NGINX real ip

Co-authored-by: Bartjan Henkemans <[email protected]>

Author: Kevinjil

provision-contest/ansible/group_vars/domserver.yml

@@ -0,0 +1,2 @@
+# If set, configure the real_ip_from header in NGINX to trust a proxy
+# NGINX_REAL_IP_FROM: 192.168.0.1

provision-contest/ansible/roles/domserver/templates/nginx-domjudge-inner.j2

@@ -69,5 +69,10 @@ add_header X-Content-Type-Options "nosniff";
 add_header X-XSS-Protection "1; mode=block";
 add_header X-Robots-Tag "none" always;
 
+{% if NGINX_REAL_IP_FROM is defined %}
+set_real_ip_from {{ NGINX_REAL_IP_FROM }};
+real_ip_header X-Forwarded-For;
+{% endif %}
+
 error_log /var/log/nginx/domjudge.log;
 access_log /var/log/nginx/domjudge.log dj_access;