fix: start nginx without resolving A-site at boot [deploy]

nginx.conf

@@ -4,15 +4,18 @@ server {
   root /usr/share/nginx/html;
   index index.html;
 
+  # 由入口脚本写入：集群 DNS + A 站地址。用变量做 proxy_pass，启动时不解析上游，A 站暂不可达也不会让 nginx 起不来。
+  resolver __RESOLVER__ valid=10s ipv6=off;
+
   location = /api/health {
     default_type text/plain;
     add_header Content-Type text/plain;
     return 200 "ok";
   }
 
-  # A 站无公网域名：浏览器只访问 B 站，由 B 反代到集群内 project57
   location /embed/ {
-    proxy_pass ${A_UPSTREAM}/embed/;
+    set $a_upstream __A_UPSTREAM__;
+    proxy_pass $a_upstream;
     proxy_http_version 1.1;
     proxy_set_header Host $host;
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
@@ -20,7 +23,8 @@ server {
   }
 
   location /images/ {
-    proxy_pass ${A_UPSTREAM}/images/;
+    set $a_upstream __A_UPSTREAM__;
+    proxy_pass $a_upstream;
     proxy_http_version 1.1;
     proxy_set_header Host $host;
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
@@ -28,7 +32,8 @@ server {
   }
 
   location = /api/contact {
-    proxy_pass ${A_UPSTREAM}/api/contact;
+    set $a_upstream __A_UPSTREAM__;
+    proxy_pass $a_upstream;
     proxy_http_version 1.1;
     proxy_set_header Host $host;
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;