diff --git a/inventory_provider/tasks/data.py b/inventory_provider/tasks/data.py
index 15527bdb7865a47fedb18e9f7cf6af78ab15f15f..4c8cd82c0507db4c7eba13c524b4ddb0960e602e 100644
--- a/inventory_provider/tasks/data.py
+++ b/inventory_provider/tasks/data.py
@@ -20,7 +20,7 @@ def build_service_interface_user_list(config):
             k = k.decode('utf-8')
             m = re.match('^netconf-interfaces:([^:]+):(.+)$', k)
             if not m:
-                logger.error('invalid redis key: "{k}"')
+                logger.error(f'unexpected redis key: "{k}"')
                 continue  # skip, rather than fail the entire update
             router_name = m.group(1)
             ifc_name = m.group(2)