throw PollsterPermenantError exception for memory usage meter

For memory usage meter, if it is not supported by libvirt and the
underlying hypervisor being used by libvirt, there is no meaning
to running the pollster again and again and so we should throw
PollsterPermenantError exception, like what l3 cache meter does.

Change-Id: I871841f2ce8f755bdeb2aff3fb063158b5c0650a
Closes-Bug: 1599344

ceilometer/compute/pollsters/memory.py

@@ -16,6 +16,7 @@
 from oslo_log import log
 
 import ceilometer
+from ceilometer.agent import plugin_base
 from ceilometer.compute import pollsters
 from ceilometer.compute.pollsters import util
 from ceilometer.compute.virt import inspector as virt_inspector
@@ -52,11 +53,17 @@ class MemoryUsagePollster(pollsters.BaseComputePollster):
                           'getting samples of %(pollster)s: %(exc)s',
                           {'instance_id': instance.id,
                            'pollster': self.__class__.__name__, 'exc': e})
-            except virt_inspector.NoDataException as e:
+            except virt_inspector.InstanceNoDataException as e:
                 LOG.warning(_LW('Cannot inspect data of %(pollster)s for '
                                 '%(instance_id)s, non-fatal reason: %(exc)s'),
                             {'pollster': self.__class__.__name__,
                              'instance_id': instance.id, 'exc': e})
+            except virt_inspector.NoDataException as e:
+                LOG.warning(_LW('Cannot inspect data of %(pollster)s for '
+                                '%(instance_id)s: %(exc)s'),
+                            {'pollster': self.__class__.__name__,
+                             'instance_id': instance.id, 'exc': e})
+                raise plugin_base.PollsterPermanentError(resources)
             except ceilometer.NotImplementedError:
                 # Selected inspector does not implement this pollster.
                 LOG.debug('Obtaining Memory Usage is not implemented for %s',

ceilometer/compute/virt/inspector.py

@@ -187,6 +187,10 @@ class InstanceShutOffException(InspectorException):
     pass
 
 
+class InstanceNoDataException(InspectorException):
+    pass
+
+
 class NoDataException(InspectorException):
     pass
 

ceilometer/compute/virt/libvirt/inspector.py

@@ -220,7 +220,7 @@ class LibvirtInspector(virt_inspector.Inspector):
                         '<name=%(name)s, id=%(id)s>, '
                         'can not get info from libvirt.') % {
                     'name': instance_name, 'id': instance.id}
-                raise virt_inspector.NoDataException(msg)
+                raise virt_inspector.InstanceNoDataException(msg)
         # memoryStats might launch an exception if the method is not supported
         # by the underlying hypervisor being used by libvirt.
         except libvirt.libvirtError as e:

ceilometer/tests/unit/compute/pollsters/test_memory.py

@@ -16,6 +16,7 @@
 import mock
 
 from ceilometer.agent import manager
+from ceilometer.agent import plugin_base
 from ceilometer.compute.pollsters import memory
 from ceilometer.compute.virt import inspector as virt_inspector
 from ceilometer.tests.unit.compute.pollsters import base
@@ -31,7 +32,7 @@ class TestMemoryPollster(base.TestPollsterBase):
         next_value = iter((
             virt_inspector.MemoryUsageStats(usage=1.0),
             virt_inspector.MemoryUsageStats(usage=2.0),
-            virt_inspector.NoDataException(),
+            virt_inspector.InstanceNoDataException(),
             virt_inspector.InstanceShutOffException(),
         ))
 
@@ -66,6 +67,24 @@ class TestMemoryPollster(base.TestPollsterBase):
         _verify_memory_metering(0, 0, 1)
         _verify_memory_metering(0, 0, 0)
 
+    @mock.patch('ceilometer.pipeline.setup_pipeline', mock.MagicMock())
+    def test_get_samples_with_empty_stats(self):
+
+        def inspect_memory_usage(instance, duration):
+            raise virt_inspector.NoDataException()
+
+        self.inspector.inspect_memory_usage = mock.Mock(
+            side_effect=inspect_memory_usage)
+
+        mgr = manager.AgentManager()
+        pollster = memory.MemoryUsagePollster()
+
+        def all_samples():
+            return list(pollster.get_samples(mgr, {}, [self.instance]))
+
+        self.assertRaises(plugin_base.PollsterPermanentError,
+                          all_samples)
+
 
 class TestResidentMemoryPollster(base.TestPollsterBase):
 

ceilometer/tests/unit/compute/virt/libvirt/test_inspector.py

@@ -336,7 +336,7 @@ class TestLibvirtInspection(base.BaseTestCase):
                                                  2, 999999)):
                 with mock.patch.object(self.domain, 'memoryStats',
                                        return_value={}):
-                    self.assertRaises(virt_inspector.NoDataException,
+                    self.assertRaises(virt_inspector.InstanceNoDataException,
                                       self.inspector.inspect_memory_usage,
                                       self.instance)