QuotaInformation : abstract resource recording

Change I670d4bfd7d35ce1109b3ee9b3342fb45ee283a79 added the
quota['compute'] property to ZK nodes for Zuul to keep track of.

Instead of accessing the property directly, this adds a
get_resources() function to QuotaInformation which returns it, and
makes a point to note that the property is used so that we don't
modify it in incompatible ways in future.

This is a no-op refactor, but helpful in a follow-on change that also
adds this field to leaked nodes.

Change-Id: Id78b059cf2121e01e4cd444f6ad3834373cf7fb6

nodepool/driver/openstack/handler.py

@@ -156,7 +156,7 @@ class OpenStackNodeLauncher(NodeLauncher):
         pool = self.handler.provider.pools.get(self.node.pool)
         resources = self.handler.manager.quotaNeededByLabel(
             self.node.type[0], pool)
-        self.node.resources = resources.quota['compute']
+        self.node.resources = resources.get_resources()
         if username:
             self.node.username = username
 

nodepool/driver/utils.py

@@ -122,6 +122,10 @@ class QuotaInformation:
         :param ram:
         :param default:
         '''
+        # Note that the self.quota['compute'] map is inserted into ZK as
+        # a node property (via get_resources) and is consumed by Zuul to
+        # calculate resource usage.  Thus care should be taken if
+        # modifying fields below.
         self.quota = {
             'compute': {
                 'cores': self._get_default(cores, default),
@@ -173,6 +177,10 @@ class QuotaInformation:
                     return False
         return True
 
+    def get_resources(self):
+        '''Return resources value to register in ZK node'''
+        return self.quota['compute']
+
     def __str__(self):
         return str(self.quota)