VMware: Add utility method to retrieve remote objects

Added a utility method that can retrieve the properties of objects
that are within a parent object in the vCenter server. With
existing utility methods, this is not possible without making multiple
api calls.

This patch partially re-adds the changes reverted by change-id
Ia3a6e3f502282d44473d4908f68d71a97167e85f.

Change-Id: I9a461b2cdde906d4f25af513b4c0410b35e82209

nova/tests/virt/vmwareapi/test_vim_util.py

@@ -40,6 +40,12 @@ def _fake_get_object_properties_missing(vim, collector, mobj,
 
 class VMwareVIMUtilTestCase(test.NoDBTestCase):
 
+    def setUp(self):
+        super(VMwareVIMUtilTestCase, self).setUp()
+        fake.reset(vc=True)
+        self.vim = fake.FakeVim()
+        self.vim._login()
+
     def test_get_dynamic_properties_missing(self):
         self.useFixture(fixtures.MonkeyPatch(
                 'nova.virt.vmwareapi.vim_util.get_object_properties',
@@ -97,3 +103,15 @@ class VMwareVIMUtilTestCase(test.NoDBTestCase):
         res = vim_util.get_dynamic_properties('fake-vim', 'fake-obj',
                                               'fake-type', 'fake-property')
         self.assertEqual({}, res)
+
+    def test_get_inner_objects(self):
+        property = ['summary.name']
+        # Get the fake datastores directly from the cluster
+        cluster_refs = fake._get_object_refs('ClusterComputeResource')
+        cluster = fake._get_object(cluster_refs[0])
+        expected_ds = cluster.datastore.ManagedObjectReference
+        # Get the fake datastores using inner objects utility method
+        result = vim_util.get_inner_objects(
+            self.vim, cluster_refs[0], 'datastore', 'Datastore', property)
+        datastores = [oc.obj for oc in result.objects]
+        self.assertEqual(expected_ds, datastores)

nova/virt/vmwareapi/fake.py

@@ -1245,11 +1245,27 @@ class FakeVim(object):
         for obj in objs:
             try:
                 obj_ref = obj.obj
-                # This means that we are doing a search for the managed
-                # data objects of the type in the inventory
                 if obj_ref == "RootFolder":
+                    # This means that we are retrieving props for all managed
+                    # data objects of the specified 'type' in the entire
+                    # inventory. This gets invoked by vim_util.get_objects.
                     mdo_refs = _db_content[type]
+                elif obj_ref.type != type:
+                    # This means that we are retrieving props for the managed
+                    # data objects in the parent object's 'path' property.
+                    # This gets invoked by vim_util.get_inner_objects
+                    # eg. obj_ref = <ManagedObjectReference of a cluster>
+                    #     type = 'DataStore'
+                    #     path = 'datastore'
+                    # the above will retrieve all datastores in the given
+                    # cluster.
+                    parent_mdo = _db_content[obj_ref.type][obj_ref]
+                    path = obj.selectSet[0].path
+                    mdo_refs = parent_mdo.get(path).ManagedObjectReference
                 else:
+                    # This means that we are retrieving props of the given
+                    # managed data object. This gets invoked by
+                    # vim_util.get_properties_for_a_collection_of_objects.
                     mdo_refs = [obj_ref]
 
                 for mdo_ref in mdo_refs:

nova/virt/vmwareapi/vim_util.py

@@ -217,6 +217,26 @@ def get_objects(vim, type, properties_to_collect=None, all=False):
             specSet=[property_filter_spec], options=options)
 
 
+def get_inner_objects(vim, base_obj, path, inner_type,
+                      properties_to_collect=None, all=False):
+    """Gets the list of inner objects of the type specified."""
+    client_factory = vim.client.factory
+    base_type = base_obj._type
+    traversal_spec = build_traversal_spec(client_factory, 'inner', base_type,
+                                          path, False, [])
+    object_spec = build_object_spec(client_factory, base_obj, [traversal_spec])
+    property_spec = build_property_spec(client_factory, type=inner_type,
+                                properties_to_collect=properties_to_collect,
+                                all_properties=all)
+    property_filter_spec = build_property_filter_spec(client_factory,
+                                [property_spec], [object_spec])
+    options = client_factory.create('ns0:RetrieveOptions')
+    options.maxObjects = CONF.vmware.maximum_objects
+    return vim.RetrievePropertiesEx(
+            vim.get_service_content().propertyCollector,
+            specSet=[property_filter_spec], options=options)
+
+
 def cancel_retrieve(vim, token):
     """Cancels the retrieve operation."""
     return vim.CancelRetrievePropertiesEx(