Implement protection against orphaned software instances.

Treat tree of software instance as graph and simulate requested changes.
Before doing any real changes check if graph is still connected.

Add utility method to software instance class in order to use collections
module and have fast graph walking.

master/bt5/vifib_base/DocumentTemplateItem/SoftwareInstance.py

@@ -29,6 +29,10 @@ from AccessControl import ClassSecurityInfo
 from Products.ERP5Type import Permissions
 from Products.ERP5.Document.Item import Item
 from lxml import etree
+import collections
+
+class DisconnectedSoftwareTree(Exception):
+  pass
 
 class SoftwareInstance(Item):
   """
@@ -60,3 +64,22 @@ class SoftwareInstance(Item):
           value = element.text
         result_dict[key] = value
     return result_dict
+
+  security.declareProtected(Permissions.AccessContentsInformation,
+    'checkDisconnected')
+  def checkDisconnected(self, graph, root):
+    size = len(graph)
+    visited = set()
+    to_crawl = collections.deque(graph[root])
+    while to_crawl:
+      current = to_crawl.popleft()
+      if current in visited:
+        continue
+      visited.add(current)
+      node_children = set(graph[current])
+      to_crawl.extend(node_children - visited)
+    # add one to visited, as root won't be visited, only children
+    # this is false positive in case of cyclic graphs, but they are
+    # anyway wrong in Software Instance trees
+    if size != len(visited) + 1:
+      raise DisconnectedSoftwareTree

master/bt5/vifib_base/WorkflowTemplateItem/portal_workflow/software_instance_slap_interface_workflow/scripts/SoftwareInstance_requestSoftwareInstance.xml

@@ -64,9 +64,12 @@ instance_xml = kwargs["instance_xml"]\n
 sla_xml = kwargs["sla_xml"]\n
 state = kwargs["state"]\n
 \n
-# Get root software instance\n
+# graph allows to "simulate" tree change after requested operation\n
+graph = {}\n
+# Get root software instance and create initial graph\n
 predecessor_software_instance = software_instance\n
 while (predecessor_software_instance is not None):\n
+  graph[predecessor_software_instance.getUid()] = predecessor_software_instance.getPredecessorUidList()\n
   root_software_instance = predecessor_software_instance\n
   predecessor_software_instance = predecessor_software_instance.getPredecessorRelatedValue(\n
       portal_type="Software Instance")\n
@@ -130,6 +133,8 @@ else:\n
     predecessor_software_instance.edit(\n
       predecessor_uid_list=predecessor_uid_list,\n
       activate_kw={\'tag\': tag},)\n
+    graph[predecessor_software_instance.getUid()] = predecessor_uid_list\n
+\n
   if state == \'started\':\n
     request_software_instance.startRequested()\n
     request_software_instance.activate(after_tag=tag).requestStartComputerPartition()\n
@@ -139,7 +144,16 @@ else:\n
   else:\n
     raise ValueError(\'State %r is not supported\' % state)\n
 predecessor_list = software_instance.getPredecessorList() + [request_software_instance.getRelativeUrl()]\n
+# Add requested software instance to graph if does not exists there yet\n
+if not request_software_instance.getUid() in graph:\n
+  graph[request_software_instance.getUid()] = []\n
+\n
+# update graph to reflect requested operation\n
+graph[software_instance.getUid()] = software_instance.getPredecessorUidList() + [request_software_instance.getUid()]\n
 \n
+# check if all elements are still connected\n
+script.log(graph, root_software_instance.getUid())\n
+software_instance.checkDisconnected(graph, root_software_instance.getUid())\n
 \n
 software_instance.edit(\n
   predecessor_list=predecessor_list,\n

master/bt5/vifib_base/bt/revision

-246
+247
\ No newline at end of file