diff --git a/progs/registry.mtail b/progs/registry.mtail
index f55bbff..2f0123b 100644
--- a/progs/registry.mtail
+++ b/progs/registry.mtail
@@ -40,9 +40,15 @@ counter registry_push_upload_seconds_total by repo, user, node
 }
 
 /$/ {
-  repo == "" { repo = "unknown" }
-  user == "" { user = "anonymous" }
-  node == "" { node = "unknown" }
+  if repo == "" {
+    repo = "unknown"
+  }
+  if user == "" {
+    user = "anonymous"
+  }
+  if node == "" {
+    node = "unknown"
+  }
 }
 
 /"upstream_range":"([0-9]+)-([0-9]+)"/ {