diff --git a/observer/messages/crawler_manager.go b/observer/messages/crawler_manager.go
index db38454..d88bd51 100644
--- a/observer/messages/crawler_manager.go
+++ b/observer/messages/crawler_manager.go
@@ -3,6 +3,10 @@ package messages
 
 const (
 	CRAWLER_READY = "CRAWLER_READY"
-	ADD_SENSOR_2_END = "ADD_SENSOR_2_END"
+	CRAWLER_STOPPED = "CRAWLER_STOPPED"
+	CRAWLER_SENSOR_ADD_DONE = "CRAWLER_SENSOR_ADD_DONE"
+	CRAWLER_SENSOR_REMOVE_DONE = "CRAWLER_SENSOR_REMOVE_DONE"
+	CRAWLER_SENSOR_UPDATE_DONE = "CRAWLER_SENSOR_UPDATE_DONE"
+	CRAWLER_UPDATE_DONE = "CRAWLER_UPDATE_DONE"
 
 )
\ No newline at end of file