fix(engine): sync outputs before printing stats at shutdown

Signed-off-by: Luca Guerra <[email protected]>

userspace/falco/app/actions/process_events.cpp

@@ -585,6 +585,12 @@ falco::app::run_result falco::app::actions::process_events(falco::app::state& s)
 		}
 	}
 
+	// By deleting s.outputs, we make sure that the engine will wait until
+	// regular output has been completely sent before printing stats, avoiding
+	// intermixed stats with output.
+	// Note that this will only work if this is the last reference held by the
+	// shared pointer.
+	s.outputs.reset();
 	s.engine->print_stats();
 
 	return res;