Move instance counter into its own pollster

There's no need to emit a counter in a specific pollster doing something
else like CPU polling.

Change-Id: If2adc861be4fec3b414d9688cf36219f6a7b04e8
Signed-off-by: Julien Danjou <julien@danjou.info>

ceilometer/compute/libvirt.py

@@ -79,6 +79,16 @@ def make_vnic_counter(instance, name, type, volume, vnic_data):
         )
 
 
+class InstancePollster(plugin.ComputePollster):
+
+    def get_counters(self, manager, instance):
+        yield make_counter_from_instance(instance,
+                                         name='instance',
+                                         type=counter.TYPE_CUMULATIVE,
+                                         volume=1,
+        )
+
+
 class DiskIOPollster(plugin.ComputePollster):
 
     LOG = log.getLogger(__name__ + '.diskio')
@@ -150,11 +160,6 @@ class CPUPollster(plugin.ComputePollster):
                                              type=counter.TYPE_CUMULATIVE,
                                              volume=cpu_info['cpu_time'],
                                              )
-            yield make_counter_from_instance(instance,
-                                             name='instance',
-                                             type=counter.TYPE_CUMULATIVE,
-                                             volume=1,
-                                             )
         except Exception as err:
             self.LOG.error('could not get CPU time for %s: %s',
                            instance.uuid, err)

setup.py

@@ -65,6 +65,7 @@ setuptools.setup(
     libvirt_diskio = ceilometer.compute.libvirt:DiskIOPollster
     libvirt_cpu = ceilometer.compute.libvirt:CPUPollster
     libvirt_net = ceilometer.compute.libvirt:NetPollster
+    libvirt_instance = ceilometer.compute.libvirt:InstancePollster
 
     [ceilometer.poll.central]
     network_floatingip = ceilometer.network.floatingip:FloatingIPPollster

tests/compute/test_libvirt.py

@@ -41,6 +41,23 @@ import mox
 import re
 
 
+class TestInstancePollster(unittest.TestCase):
+
+    @skip.skip_if(libvirt_missing, 'Test requires libvirt')
+    def setUp(self):
+        self.manager = manager.AgentManager()
+        self.pollster = libvirt.InstancePollster()
+        super(TestInstancePollster, self).setUp()
+        self.instance = mock.MagicMock()
+        self.instance.name = 'instance-00000001'
+        self.instance.id = 1
+        flags.FLAGS.compute_driver = 'libvirt.LibvirtDriver'
+        flags.FLAGS.connection_type = 'libvirt'
+
+    def test_get_counter(self):
+        list(self.pollster.get_counters(self.manager, self.instance))
+
+
 class TestDiskIOPollster(unittest.TestCase):
 
     def setUp(self):