Fix metering agent failure when chain missing

The metering agent will fail if one of the iptables chains
is missing, which will cause errors extracting data from
all the other chains. Add a simple try/except to let the
loop continue.

Closes-Bug: #1421037

Change-Id: I370ee0e2cc58ca7e1c5ef9bf4dbcce5abf7545a1

diff --git a/neutron/services/metering/drivers/iptables/iptables_driver.py b/neutron/services/metering/drivers/iptables/iptables_driver.py
index 8bdec808c73d14b110043455ebf46988a2d0eabc..0e828f096f89f54567c1372a6e373cf8dc374967 100644 (file)
--- a/neutron/services/metering/drivers/iptables/iptables_driver.py
+++ b/neutron/services/metering/drivers/iptables/iptables_driver.py
@@ -23,7 +23,7 @@ from neutron.agent.linux import iptables_manager
 from neutron.common import constants as constants
 from neutron.common import ipv6_utils
 from neutron.common import log
-from neutron.i18n import _LI
+from neutron.i18n import _LE, _LI
 from neutron.services.metering.drivers import abstract_driver
 
 
@@ -266,11 +266,18 @@ class IptablesMeteringDriver(abstract_driver.MeteringAbstractDriver):
                 continue
 
             for label_id, label in rm.metering_labels.items():
-                chain = iptables_manager.get_chain_name(WRAP_NAME + LABEL +
-                                                        label_id, wrap=False)
+                try:
+                    chain = iptables_manager.get_chain_name(WRAP_NAME +
+                                                            LABEL +
+                                                            label_id,
+                                                            wrap=False)
 
-                chain_acc = rm.iptables_manager.get_traffic_counters(
-                    chain, wrap=False, zero=True)
+                    chain_acc = rm.iptables_manager.get_traffic_counters(
+                        chain, wrap=False, zero=True)
+                except RuntimeError:
+                    LOG.exception(_LE('Failed to get traffic counters, '
+                                      'router: %s'), router)
+                    continue
 
                 if not chain_acc:
                     continue

diff --git a/neutron/tests/unit/services/metering/drivers/test_iptables_driver.py b/neutron/tests/unit/services/metering/drivers/test_iptables_driver.py
index 292a7983963ce3b587a8fef1d831e772a560f542..45dd320272128119258507fafb87ec8a685f4ace 100644 (file)
--- a/neutron/tests/unit/services/metering/drivers/test_iptables_driver.py
+++ b/neutron/tests/unit/services/metering/drivers/test_iptables_driver.py
@@ -360,3 +360,19 @@ class IptablesDriverTestCase(base.BaseTestCase):
                                         wrap=False)]
 
         self.v4filter_inst.assert_has_calls(calls)
+
+    def test_get_traffic_counters_with_missing_chain(self):
+        for r in TEST_ROUTERS:
+            rm = iptables_driver.RouterWithMetering(self.metering.conf, r)
+            rm.metering_labels = {r['_metering_labels'][0]['id']: 'fake'}
+            self.metering.routers[r['id']] = rm
+
+        mocked_method = self.iptables_cls.return_value.get_traffic_counters
+        mocked_method.side_effect = [{'pkts': 1, 'bytes': 8},
+                                     RuntimeError('Failed to find the chain')]
+
+        counters = self.metering.get_traffic_counters(None, TEST_ROUTERS)
+        expected_label_id = TEST_ROUTERS[0]['_metering_labels'][0]['id']
+        self.assertIn(expected_label_id, counters)
+        self.assertEqual(1, counters[expected_label_id]['pkts'])
+        self.assertEqual(8, counters[expected_label_id]['bytes'])