Hoist variables for proxied hostnames

This allows them to be more easily changed locally.

group_vars/all.yml

@@ -18,13 +18,15 @@ certbot_create_standalone_stop_services:
 # competition. It is required for the competition pages, including the
 # competition homepage.
 enable_srcomp_proxy: false
+srcomp_proxy_hostname: srcomp.studentrobotics.org
 # Override serving of the root url to be the competition mode homepage instead
 # of the normal one.
 enable_competition_homepage: false
 
 # We typically only host the competitor services for the duration of the
 # competition year.
 enable_competitor_services_proxy: true
+competitor_services_proxy_hostname: competitorsvcs.studentrobotics.org
 
 firewall_allowed_tcp_ports:
  - "22"

roles/srobo-nginx/templates/nginx.conf

@@ -121,7 +121,7 @@ http {
         # When the proxied service is not available NGINX will refuse to start.
         # Use a variable to trick it into connecting lazily and thus always
         # starting up, even if in a degraded mode.
-        set $competitorsvcs 'competitorsvcs.studentrobotics.org';
+        set $competitorsvcs '{{ competitor_services_proxy_hostname }}';
         proxy_pass https://$competitorsvcs/code-submitter/;
         # Note: don't set a Host header as we want the code-submitter to use our
         # public hostname, not the hostname of the underlying machine.
@@ -133,7 +133,7 @@ http {
         # When the proxied service is not available NGINX will refuse to start.
         # Use a variable to trick it into connecting lazily and thus always
         # starting up, even if in a degraded mode.
-        set $srcomp 'srcomp.studentrobotics.org';
+        set $srcomp '{{ srcomp_proxy_hostname }}';
         proxy_pass https://$srcomp/comp-api/;
       }