diff --git a/docker/nginx/nginx.conf b/docker/nginx/nginx.conf
index c71ead18..22dcd4a7 100644
--- a/docker/nginx/nginx.conf
+++ b/docker/nginx/nginx.conf
@@ -67,9 +67,9 @@ http {
     #gzip  on;
 
     # expose env variables as regular variables (env variables are not easily accessible in nginx)
-    perl_set $SKYNET_PORTAL_API 'sub { return $ENV{"SKYNET_PORTAL_API"}; }';
-    perl_set $SKYNET_SERVER_API 'sub { return $ENV{"SKYNET_SERVER_API"}; }';
-    perl_set $ACCOUNTS_ENABLED 'sub { return $ENV{"ACCOUNTS_ENABLED"}; }';
+    set_by_lua $SKYNET_PORTAL_API 'return os.getenv("SKYNET_PORTAL_API")';
+    set_by_lua $SKYNET_SERVER_API 'return os.getenv("SKYNET_SERVER_API")';
+    set_by_lua $ACCOUNTS_ENABLED 'return os.getenv("ACCOUNTS_ENABLED")';
 
     # include skynet-portal-api header on every request
     header_filter_by_lua 'ngx.header["Skynet-Portal-Api"] = os.getenv("SKYNET_PORTAL_API")';