Implement zvm inspector helper function - _get_inst_stat

In _get_inst_stat, would check cache data expir or not, then update
cache if needed, at last, return instance data per latest cache.

Change-Id: Iaa499622f1f4e38182a50249f8c63b02e7a36465

ceilometer_zvm/compute/virt/zvm/inspector.py

@@ -106,6 +106,28 @@ class ZVMInspector(virt_inspector.Inspector):
         if meter in ('cpus', 'memory.usage'):
             self._update_inst_cpu_mem_stat(instances)
 
+    def _check_expiration_and_update_cache(self, meter):
+        now = timeutils.utcnow_ts()
+        if now >= self.cache_expiration:
+            self._update_cache(meter)
+
+    def _get_inst_stat(self, meter, instance):
+        self._check_expiration_and_update_cache(meter)
+
+        inst_name = zvmutils.get_inst_name(instance)
+        inst_stat = self.cache.get(inst_name)
+
+        if inst_stat is None:
+            userid = (self.instances.get(inst_name) or
+                        zvmutils.get_userid(inst_name))
+            self._update_cache(meter, {inst_name: userid})
+            inst_stat = self.cache.get(inst_name)
+
+        if inst_stat is None:
+            raise virt_inspector.InstanceNotFoundException()
+        else:
+            return inst_stat
+
     def inspect_cpus(self, instance):
         pass
 

ceilometer_zvm/compute/virt/zvm/utils.py

@@ -365,3 +365,7 @@ def image_performance_query(zhcp_node, inst_list):
             pi_dict[pi['userid']] = pi
 
     return pi_dict
+
+
+def get_inst_name(instance):
+    return getattr(instance, 'OS-EXT-SRV-ATTR:instance_name', None)

ceilometer_zvm/tests/unit/compute/virt/zvm/test_inspector.py

@@ -15,7 +15,9 @@
 
 import mock
 
+from ceilometer.compute.virt import inspector as virt_inspertor
 from oslo_config import fixture as fixture_config
+from oslo_utils import timeutils
 from oslotest import base
 
 from ceilometer_zvm.compute.virt.zvm import inspector as zvm_inspector
@@ -85,3 +87,62 @@ class TestZVMInspector(base.BaseTestCase):
         inst = {'inst1': 'INST1'}
         self.inspector._update_cache('memory.usage', inst)
         upd.assert_called_with(inst)
+
+    @mock.patch("ceilometer_zvm.compute.virt.zvm.inspector.ZVMInspector."
+                "_update_cache")
+    def test_check_expiration_and_update_cache(self, udc):
+        self.inspector._check_expiration_and_update_cache('cpus')
+        udc.assert_called_once_with('cpus')
+
+    @mock.patch("ceilometer_zvm.compute.virt.zvm.inspector.ZVMInspector."
+                "_update_cache")
+    def test_check_expiration_and_update_cache_no_update(self, udc):
+        self.inspector.cache_expiration = timeutils.utcnow_ts() + 100
+        self.inspector._check_expiration_and_update_cache('cpus')
+        udc.assert_not_called()
+
+    @mock.patch.object(zvmutils, 'get_inst_name')
+    @mock.patch("ceilometer_zvm.compute.virt.zvm.inspector.ZVMInspector."
+                "_check_expiration_and_update_cache")
+    def test_get_inst_stat(self, check_update, get_name):
+        get_name.return_value = 'inst1'
+        self.inspector.cache.set({'guest_cpus': 2, 'nodename': 'inst1'})
+
+        inst_stat = self.inspector._get_inst_stat('cpus', {'inst1': 'INST1'})
+        self.assertEqual(2, inst_stat['guest_cpus'])
+        check_update.assert_called_once_with('cpus')
+
+    @mock.patch("ceilometer_zvm.compute.virt.zvm.inspector.ZVMInspector."
+                "_update_cache")
+    @mock.patch.object(zvmutils, 'get_userid')
+    @mock.patch.object(zvmutils, 'get_inst_name')
+    @mock.patch("ceilometer_zvm.compute.virt.zvm.inspector.ZVMInspector."
+                "_check_expiration_and_update_cache")
+    def test_get_inst_stat_not_found(self, check_update, get_name,
+                                     get_uid, update):
+        get_name.return_value = 'inst1'
+        get_uid.return_value = 'INST1'
+
+        self.assertRaises(virt_inspertor.InstanceNotFoundException,
+                          self.inspector._get_inst_stat, 'cpus',
+                          {'inst1': 'INST1'})
+        check_update.assert_called_once_with('cpus')
+        update.assert_called_once_with('cpus', {'inst1': 'INST1'})
+
+    @mock.patch("ceilometer_zvm.compute.virt.zvm.inspector.ZVMInspector."
+                "_update_cache")
+    @mock.patch.object(zvmutils, 'get_userid')
+    @mock.patch("ceilometer_zvm.compute.virt.zvm.utils.CacheData.get")
+    @mock.patch.object(zvmutils, 'get_inst_name')
+    @mock.patch("ceilometer_zvm.compute.virt.zvm.inspector.ZVMInspector."
+                "_check_expiration_and_update_cache")
+    def test_get_inst_stat_update_cache(self, check_update, get_name,
+                                        cache_get, get_uid, update):
+        get_name.return_value = 'inst1'
+        cache_get.side_effect = [None, {'guest_cpus': 2, 'nodename': 'inst1'}]
+        get_uid.return_value = 'INST1'
+
+        inst_stat = self.inspector._get_inst_stat('cpus', {'inst1': 'INST1'})
+        self.assertEqual(2, inst_stat['guest_cpus'])
+        check_update.assert_called_once_with('cpus')
+        update.assert_called_once_with('cpus', {'inst1': 'INST1'})

tox.ini

@@ -28,7 +28,7 @@ commands = {posargs}
 commands = python setup.py testr --coverage --testr-args='{posargs}'
 
 [flake8]
-ignore = E126,E128
+ignore = E126,E127,E128
 exclude =  .venv,.git,.tox,dist,doc,*egg,build
 
 [hacking]