Add ability to configure Nginx DNS resolver (#3275)

Author: sarayourfriend

docker-compose.yml

@@ -334,6 +334,10 @@ services:
     environment:
       OPENVERSE_NGINX_UPSTREAM_URL: ${HOST_NETWORK_ADDRESS}:8443
       OPENVERSE_NGINX_PLAUSIBLE_EVENT_URL: http://plausible:8000/api/event
+      # Set to Docker network resolver to be able to resolve the `plausible` container.
+      # This would be the default but Nginx requires it to be explicitly set when
+      # making outgoing requests (e.g., to plausible.io)
+      OPENVERSE_NGINX_DNS_RESOLVER: 127.0.0.11
 
 volumes:
   api-postgres:

frontend/nginx.conf.template

@@ -5,6 +5,7 @@
 # - OPENVERSE_NGINX_GIT_REVISION
 # - OPENVERSE_NGINX_ENVIRONMENT
 # - OPENVERSE_NGINX_PLAUSIBLE_EVENT_URL
+# - OPENVERSE_NGINX_DNS_RESOLVER
 
 error_log /var/log/nginx/error.log;
 
@@ -69,7 +70,7 @@ server {
     # This is Docker's internal DNS resolver
     # In localhost it will resolve the local Plausible and forward anything else to the host
     # In production, AWS replaces
-    resolver 127.0.0.11;
+    resolver $OPENVERSE_NGINX_DNS_RESOLVER;
     set $plausible_event_url $OPENVERSE_NGINX_PLAUSIBLE_EVENT_URL;
     location = /api/event {
         proxy_pass $plausible_event_url;