fix(loki-gateway): escape dollar signs for templating

- Ensure correct Nginx variable rendering
- Remove obsolete Nginx config comments

Author: JOELNATHAN544

lgtm-stack/terraform/values/loki-values.yaml

@@ -147,11 +147,6 @@ gateway:
       mountPath: /etc/nginx/secrets
       readOnly: true
 
-  # Custom nginx config:
-  #   - Push paths (distributor): no auth -- agents use X-Scope-OrgID directly
-  #   - Read paths (query-frontend): BasicAuth required
-  #     Grafana's data proxy sends the per-tenant credentials stored in Grafana DB.
-  #     Non-members get 401 even if they can see the datasource name in the UI.
   nginxConfig:
     file: |
       worker_processes  5;
@@ -168,22 +163,18 @@ gateway:
         uwsgi_temp_path       /tmp/uwsgi_temp;
         scgi_temp_path        /tmp/scgi_temp;
         default_type application/octet-stream;
-        log_format  main '$$remote_addr - $$remote_user [$$time_local] "$$request" $$status';
-        access_log  /dev/stderr  main;
+        log_format main '{{ print "$" }}remote_addr - {{ print "$" }}remote_user [{{ print "$" }}time_local] "{{ print "$" }}request" {{ print "$" }}status';
+        access_log /dev/stderr main;
         server {
           listen 8080;
-
-          # -- Write path (no auth -- agents push directly with X-Scope-OrgID) --
           location ~ ^/(loki/api/v1/push|loki/api/v1/tail|ready|log) {
-            proxy_pass       http://monitoring-loki-distributor.observability.svc.cluster.local:3100;
+            proxy_pass http://monitoring-loki-distributor.observability.svc.cluster.local:3100;
             proxy_http_version 1.1;
           }
-
-          # -- Read path (BasicAuth required -- only valid tenant credentials pass) --
           location / {
-            auth_basic           "Loki Tenant Authentication";
+            auth_basic "Loki Tenant Authentication";
             auth_basic_user_file /etc/nginx/secrets/.htpasswd;
-            proxy_pass       http://monitoring-loki-query-frontend.observability.svc.cluster.local:3100;
+            proxy_pass http://monitoring-loki-query-frontend.observability.svc.cluster.local:3100;
             proxy_http_version 1.1;
           }
         }