Merge pull request #130 from alphagov/add-server-timing-cache-header

Add cache state to Server-Timing header
alphagov · Jan 10, 2025 · 88141ba · 88141ba
2 parents bde0ee3 + 085eea9
commit 88141ba
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/www/www.vcl.tftpl b/www/www.vcl.tftpl
@@ -544,6 +544,12 @@ sub vcl_miss {
 sub vcl_deliver {
   set resp.http.Strict-Transport-Security = "max-age=31536000; preload";
 
+  if (fastly_info.state ~ "^HIT") {
+    set resp.http.Server-Timing:cacheHit = "";
+  } else if (fastly_info.state ~ "^MISS") {
+    set resp.http.Server-Timing:cacheMiss = "";
+  }
+
   # GOV.UK accounts
   if (resp.http.GOVUK-Account-End-Session) {
     add resp.http.Set-Cookie = "__Host-govuk_account_session=; secure; httponly; samesite=lax; path=/; max-age=0";