Add resources dict into _Provider

Add resources dict into _Provider, which is similar to inventory,
and _Provider.resources will contain some resource details but not
resource amount in inventory, which will be Resource object set
keyed by resource class. We can populate this from update provider
tree.

Change-Id: If37aaff1e3652692fd0750e98612f3b040019042
Partially-Implements: blueprint virtual-persistent-memory
Co-Authored-By: He Jie Xu <hejie.xu@intel.com>

nova/compute/provider_tree.py

@@ -41,7 +41,7 @@ _LOCK_NAME = 'provider-tree-lock'
 # doesn't make a moustache appear on my actual face.
 ProviderData = collections.namedtuple(
     'ProviderData', ['uuid', 'name', 'generation', 'parent_uuid', 'inventory',
-                     'traits', 'aggregates'])
+                     'traits', 'aggregates', 'resources'])
 
 
 class _Provider(object):
@@ -65,6 +65,9 @@ class _Provider(object):
         self.traits = set()
         # Set of aggregate UUIDs
         self.aggregates = set()
+        # dict of resource records, keyed by resource class
+        # the value is the set of objects.Resource
+        self.resources = {}
 
     @classmethod
     def from_dict(cls, pdict):
@@ -83,9 +86,10 @@ class _Provider(object):
         inventory = copy.deepcopy(self.inventory)
         traits = copy.copy(self.traits)
         aggregates = copy.copy(self.aggregates)
+        resources = copy.deepcopy(self.resources)
         return ProviderData(
             self.uuid, self.name, self.generation, self.parent_uuid,
-            inventory, traits, aggregates)
+            inventory, traits, aggregates, resources)
 
     def get_provider_uuids(self):
         """Returns a list, in top-down traversal order, of UUIDs of this
@@ -227,6 +231,19 @@ class _Provider(object):
         """
         return not bool(set(aggregates) - self.aggregates)
 
+    def have_resources_changed(self, new):
+        """Returns whether the resources have changed for the provider."""
+        return self.resources != new
+
+    def update_resources(self, resources):
+        """Update the stored resources for the provider. The method returns
+        whether the resources have changed.
+        """
+        if self.have_resources_changed(resources):
+            self.resources = copy.deepcopy(resources)
+            return True
+        return False
+
 
 class ProviderTree(object):
 
@@ -696,3 +713,17 @@ class ProviderTree(object):
             provider = self._find_with_lock(name_or_uuid)
             final_aggs = provider.aggregates - set(aggregates)
             provider.update_aggregates(final_aggs)
+
+    def update_resources(self, name_or_uuid, resources):
+        """Given a name or UUID of a provider and a dict of resources,
+        update the provider's resources.
+
+        :param name_or_uuid: The name or UUID of the provider whose resources
+                             are to be affected.
+        :param resources: A dict keyed by resource class, and the value is a
+                          set of objects.Resource instance.
+        :returns: True if the resources are updated else False
+        """
+        with self.lock:
+            provider = self._find_with_lock(name_or_uuid)
+            return provider.update_resources(resources)

nova/tests/unit/compute/test_provider_tree.py

@@ -696,3 +696,33 @@ class TestProviderTree(test.NoDBTestCase):
         # Remove the last aggregate, and an unrelated one
         pt.remove_aggregates(cn.uuid, uuids.agg4, uuids.agg1)
         self.assertEqual(set([]), pt.data(cn.uuid).aggregates)
+
+    def test_update_resources_no_existing_rp(self):
+        pt = self._pt_with_cns()
+        self.assertRaises(
+            ValueError,
+            pt.update_resources,
+            uuids.non_existing_rp,
+            {},
+        )
+
+    def test_update_resources(self):
+        cn = self.compute_node1
+        pt = self._pt_with_cns()
+
+        cn_resources = {
+            "CUSTOM_RESOURCE_0": {
+                objects.Resource(provider_uuid=cn.uuid,
+                                 resource_class="CUSTOM_RESOURCE_0",
+                                 identifier="bar")},
+            "CUSTOM_RESOURCE_1": {
+                objects.Resource(provider_uuid=cn.uuid,
+                                 resource_class="CUSTOM_RESOURCE_1",
+                                 identifier="foo_1"),
+                objects.Resource(provider_uuid=cn.uuid,
+                                 resource_class="CUSTOM_RESOURCE_1",
+                                 identifier="foo_2")}}
+        # resources changed
+        self.assertTrue(pt.update_resources(cn.uuid, cn_resources))
+        # resources not changed
+        self.assertFalse(pt.update_resources(cn.uuid, cn_resources))