created exception for missing terraform stack files

kypo/cloud_commons/__init__.py

@@ -5,4 +5,5 @@ from kypo.cloud_commons.exceptions import KypoException, StackException, StackCr
     InvalidTopologyDefinition
 from kypo.cloud_commons.topology_elements import MAN, SecurityGroups, Link, NodeToNodeLinkPair
 from kypo.cloud_commons.exceptions import KypoException, StackException, StackCreationFailed,\
-    InvalidTopologyDefinition
+    InvalidTopologyDefinition, StackNotFound
+from kypo.cloud_commons.cloud_client_elements import Image, Limits, QuotaSet, HardwareUsage

kypo/cloud_commons/exceptions.py

@@ -24,6 +24,13 @@ class StackCreationFailed(StackException):
     pass
 
 
+class StackNotFound(StackException):
+    """
+    This exception is raised if Terraform stack directory is not found.
+    """
+    pass
+
+
 class InvalidTopologyDefinition(KypoException):
     """
     This exception is raised if topology definition cannot be transformed.