update

nginx.conf

@@ -25,7 +25,11 @@ http {
                 -- ngx.var.proxy_pass = ngx.var.uri
                 ngx.var.upstream = 'https://baidu.com';
             }
-            proxy_pass $ngx.shared.upstream_dict["upstream"];
+            content_by_lua_block {
+                local upstream_dict = ngx.shared.upstream_dict
+                ngx.var.upstream = upstream_dict:get("upstream")
+            }
+            proxy_pass $upstream;
         }
     }
 }