Do not export if PrepareExport returns false

Author: ThomsonTan

exporters/user_events/src/logs_exporter.cc

@@ -52,9 +52,10 @@ sdk::common::ExportResult Exporter::Export(
     auto user_events_record =
         std::unique_ptr<Recordable>(static_cast<Recordable *>(record.release()));
 
-    user_events_record->PrepareExport();
-
-    // assert(user_events_record != nullptr, "Recordable is null");
+    if (!user_events_record->PrepareExport())
+    {
+      continue;
+    }
 
     int level_index = user_events_record->GetLevelIndex();
 

exporters/user_events/src/recordable.cc

@@ -104,10 +104,17 @@ void Recordable::SetTimestamp(opentelemetry::common::SystemTimestamp timestamp)
 
 bool Recordable::PrepareExport() noexcept
 {
-  if (cs_part_b_bookmark_size_ > 0)
+  if (cs_part_b_bookmark_size_ == 0)
+  {
+    // Part B is mandatory for exporting to user_events.
+    OTEL_INTERNAL_LOG_ERROR("[user_events Log Exporter] Recordable: no data to export.");
+    return false;
+  }
+  else
   {
     event_builder_.SetStructFieldCount(cs_part_b_bookmark_, cs_part_b_bookmark_size_);
   }
+
   if (cs_part_c_bookmark_size_ > 0)
   {
     event_builder_.SetStructFieldCount(cs_part_c_bookmark_, cs_part_c_bookmark_size_);