VMware: Handles no datastores case

If the host does not have datastores mounted or is in maintenance mode
then it reports empty datastores list. Modified code to ignore such cases.

Fixes bug: 1229653

Change-Id: I8f076d7b652181988b45738664a0d549c0b5ff9b

cinder/tests/test_vmware_vmdk.py

@@ -97,6 +97,17 @@ def __init__(self, tree=None, name=None,
         self.childSnapshotList = childSnapshotList
 
 
+class FakeElem(object):
+    def __init__(self, prop_set=None):
+        self.propSet = prop_set
+
+
+class FakeProp(object):
+    def __init__(self, name=None, val=None):
+        self.name = name
+        self.val = val
+
+
 class VMwareEsxVmdkDriverTestCase(test.TestCase):
     """Test class for VMwareEsxVmdkDriver."""
 
@@ -406,6 +417,26 @@ def test_get_dss_rp(self):
         m.UnsetStubs()
         m.VerifyAll()
 
+    def test_get_dss_rp_without_datastores(self):
+        """Test get_dss_rp without datastores."""
+        m = self.mox
+        m.StubOutWithMock(api.VMwareAPISession, 'vim')
+        self._session.vim = self._vim
+        m.StubOutWithMock(self._session, 'invoke_api')
+        host = FakeObject()
+        props = [FakeElem(prop_set=[FakeProp(name='datastore')])]
+        self._session.invoke_api(vim_util, 'get_object_properties',
+                                 self._vim, host,
+                                 ['datastore', 'parent']).AndReturn(props)
+        self._session.invoke_api(vim_util, 'get_object_property',
+                                 self._vim, mox.IgnoreArg(), 'resourcePool')
+
+        m.ReplayAll()
+        self.assertRaises(error_util.VimException, self._volumeops.get_dss_rp,
+                          host)
+        m.UnsetStubs()
+        m.VerifyAll()
+
     def test_get_parent(self):
         """Test get_parent."""
         # Not recursive

cinder/volume/drivers/vmware/volumeops.py

@@ -154,7 +154,8 @@ def get_dss_rp(self, host):
         compute_resource = None
         for elem in props:
             for prop in elem.propSet:
-                if prop.name == 'datastore':
+                if prop.name == 'datastore' and prop.val:
+                    # Consider only if datastores are present under host
                     datastores = prop.val.ManagedObjectReference
                 elif prop.name == 'parent':
                     compute_resource = prop.val