fix(ui): replace variable in nginx.conf

Author: luis-dk

deploy/docker/observability-ui.dockerfile

@@ -22,7 +22,10 @@ FROM ${BASE_IMAGE_URL}nginxinc/nginx-unprivileged:1.25
 
 WORKDIR /observability_ui
 
+ENV OBSERVABILITY_API_HOSTNAME=
+ENV NGINX_ENVSUBST_OUTPUT_DIR=/etc/nginx
+
 COPY --from=build-image --chown=nginx:nginx /observability_ui/dist /observability_ui
-COPY --from=build-image --chown=nginx:nginx /observability_ui/nginx.conf /etc/nginx/nginx.conf
+COPY --from=build-image --chown=nginx:nginx /observability_ui/nginx.conf /etc/nginx/templates/nginx.conf.template
 
 RUN mv /observability_ui/auth /observability_ui/shell/

observability_ui/nginx.conf

@@ -57,11 +57,12 @@ http {
     location / {
       sub_filter_once off;
       sub_filter RandomNonceValue $request_id;
+      set $api_hostname "$OBSERVABILITY_API_HOSTNAME";
 
       try_files /shell$uri /shell/index.html =404;
 
       add_header X-Content-Type-Options nosniff always;
-      add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'nonce-${request_id}' https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline' https://cdn.materialdesignicons.com https://cdn.jsdelivr.net; img-src 'self' data:; font-src 'self' https://fonts.gstatic.com https://cdn.jsdelivr.net; frame-ancestors 'none'; connect-src 'self' https://fonts.gstatic.com https://cdn.materialdesignicons.com https://cdn.jsdelivr.net; upgrade-insecure-requests;" always;
+      add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'nonce-${request_id}' https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline' https://cdn.materialdesignicons.com https://cdn.jsdelivr.net; img-src 'self' data:; font-src 'self' https://fonts.gstatic.com https://cdn.jsdelivr.net; frame-ancestors 'none'; connect-src 'self' https://fonts.gstatic.com https://cdn.materialdesignicons.com https://cdn.jsdelivr.net ${api_hostname}; upgrade-insecure-requests;" always;
     }
   }
 }