template: add warning about unrendered binary values

It took me a while to realize why the output is not rendered in our light tests, once I removed $MSG as a macro. This message would have helped me a lot. Signed-off-by: Balazs Scheidler <[email protected]>
axoflow · Jan 6, 2025 · 5da76da · 5da76da
1 parent d13b7c5
commit 5da76da
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/lib/template/eval.c b/lib/template/eval.c
@@ -75,6 +75,10 @@ log_template_append_elem_value(LogTemplate *self, LogTemplateElem *e, LogTemplat
     }
   else if (value_type == LM_VT_BYTES || value_type == LM_VT_PROTOBUF)
     {
+      msg_warning_once("template: not rendering binary name-value pair, use an explicit type hint",
+                       evt_tag_str("template", self->template_str),
+                       evt_tag_str("name", log_msg_get_handle_name(e->value_handle, NULL)),
+                       evt_tag_str("type", log_msg_value_type_to_str(value_type)));
       value_type = LM_VT_NULL;
     }
   *type = _propagate_type(*type, value_type);