X-Git-Url: https://osm.etsi.org/gitweb/?a=blobdiff_plain;f=juju%2Fapplication.py;h=1e87ced2e26ea1ab24de5badfb63f011c0b9a803;hb=1dd5b8bb6d597700bd5ae06e00a25f7f7d684797;hp=978500fa321ec445a9c686f7da4a3e9630d31277;hpb=2ed7314a9ea1240883655bc521b6e27f149aa485;p=osm%2FN2VC.git

diff --git a/juju/application.py b/juju/application.py
index 978500f..1e87ced 100644
--- a/juju/application.py
+++ b/juju/application.py
@@ -7,6 +7,26 @@ log = logging.getLogger(__name__)
 
 
 class Application(model.ModelEntity):
+    @property
+    def _unit_match_pattern(self):
+        return r'^{}.*$'.format(self.entity_id)
+
+    def on_unit_add(self, callable_):
+        """Add a "unit added" observer to this entity, which will be called
+        whenever a unit is added to this application.
+
+        """
+        self.model.add_observer(
+            callable_, 'unit', 'add', self._unit_match_pattern)
+
+    def on_unit_remove(self, callable_):
+        """Add a "unit removed" observer to this entity, which will be called
+        whenever a unit is removed from this application.
+
+        """
+        self.model.add_observer(
+            callable_, 'unit', 'remove', self._unit_match_pattern)
+
     @property
     def units(self):
         return [