fix ceilometer-compute invoke libvirt exception error

when nova compute start vm not create by nova-compute,
the ceilometer-compute will occur libvirtError: "metadata
not found: Requested metadata element is not present".
and cause all vm meter not report.

(cherry picked from commit c477678e574a0a4c06dd29af2dbf9f58ec934b9a)

Change-Id: Id71788606bc0da9a7959831fb90d13c25c0b8dcb

2 files changed, 74 insertions, 4 deletions

diff --git a/ceilometer/compute/discovery.py b/ceilometer/compute/discovery.py
index c5395e80..57c6a9f2 100644
--- a/ceilometer/compute/discovery.py
+++ b/ceilometer/compute/discovery.py
@@ -145,12 +145,21 @@ class InstanceDiscovery(plugin_base.DiscoveryBase):
     def discover_libvirt_polling(self, manager, param=None):
         instances = []
         for domain in self.connection.listAllDomains():
+            try:
+                xml_string = domain.metadata(
+                    libvirt.VIR_DOMAIN_METADATA_ELEMENT,
+                    "http://openstack.org/xmlns/libvirt/nova/1.0")
+            except libvirt.libvirtError as e:
+                if libvirt_utils.is_disconnection_exception(e):
+                    # Re-raise the exception so it's handled and retries
+                    raise
+                LOG.error(
+                    "Fail to get domain uuid %s metadata, libvirtError: %s",
+                    domain.UUIDString(), e.message)
+                continue
+
             full_xml = etree.fromstring(domain.XMLDesc())
             os_type_xml = full_xml.find("./os/type")
-
-            xml_string = domain.metadata(
-                libvirt.VIR_DOMAIN_METADATA_ELEMENT,
-                "http://openstack.org/xmlns/libvirt/nova/1.0")
             metadata_xml = etree.fromstring(xml_string)
 
             # TODO(sileht): We don't have the flavor ID here So the Gnocchi
diff --git a/ceilometer/tests/unit/compute/test_discovery.py b/ceilometer/tests/unit/compute/test_discovery.py
index 3eae5ea2..33fe9aaf 100644
--- a/ceilometer/tests/unit/compute/test_discovery.py
+++ b/ceilometer/tests/unit/compute/test_discovery.py
@@ -15,6 +15,12 @@ import datetime
 import fixtures
 import iso8601
 import mock
+import testtools
+
+try:
+    import libvirt
+except ImportError:
+    libvirt = None
 
 from ceilometer.compute import discovery
 from ceilometer.compute.pollsters import util
@@ -58,6 +64,21 @@ LIBVIRT_DESC_XML = """
 </domain>
 """
 
+LIBVIRT_MANUAL_INSTANCE_DESC_XML = """
+<domain type='kvm' id='1'>
+  <name>Manual-instance-00000001</name>
+  <uuid>5e637d0d-8c0e-441a-a11a-a9dc95aed84e</uuid>
+  <os>
+    <type arch='x86_64' machine='pc-i440fx-xenial'>hvm</type>
+    <kernel>/opt/instances/5e637d0d-8c0e-441a-a11a-a9dc95aed84e/kernel</kernel>
+    <initrd>/opt/instances/5e637d0d-8c0e-441a-a11a-a9dc95aed84e/ramdisk</initrd>
+    <cmdline>root=/dev/vda console=tty0 console=ttyS0</cmdline>
+    <boot dev='hd'/>
+    <smbios mode='sysinfo'/>
+  </os>
+</domain>
+"""
+
 
 class FakeDomain(object):
     def state(self):
@@ -81,6 +102,33 @@ class FakeConn(object):
         return [FakeDomain()]
 
 
+class FakeManualInstanceDomain(object):
+    def state(self):
+        return [1, 2]
+
+    def name(self):
+        return "Manual-instance-00000001"
+
+    def UUIDString(self):
+        return "5e637d0d-8c0e-441a-a11a-a9dc95aed84e"
+
+    def XMLDesc(self):
+        return LIBVIRT_MANUAL_INSTANCE_DESC_XML
+
+    def metadata(self, flags, url):
+        # Note(xiexianbin): vm not create by nova-compute don't have metadata
+        # elements like: '<nova:instance
+        #  xmlns:nova="http://openstack.org/xmlns/libvirt/nova/1.0">'
+        # When invoke get metadata method, raise libvirtError.
+        raise libvirt.libvirtError(
+            "metadata not found: Requested metadata element is not present")
+
+
+class FakeManualInstanceConn(object):
+    def listAllDomains(self):
+        return [FakeManualInstanceDomain()]
+
+
 class TestDiscovery(base.BaseTestCase):
 
     def setUp(self):
@@ -236,3 +284,16 @@ class TestDiscovery(base.BaseTestCase):
                           mock.call('test', None)]
         self.assertEqual(expected_calls,
                          self.client.instance_get_all_by_host.call_args_list)
+
+    @testtools.skipUnless(libvirt, "libvirt not available")
+    @mock.patch.object(utils, "libvirt")
+    @mock.patch.object(discovery, "libvirt")
+    def test_discovery_with_libvirt_error(self, libvirt, libvirt2):
+        self.CONF.set_override("instance_discovery_method",
+                               "libvirt_metadata",
+                               group="compute")
+        libvirt.VIR_DOMAIN_METADATA_ELEMENT = 2
+        libvirt2.openReadOnly.return_value = FakeManualInstanceConn()
+        dsc = discovery.InstanceDiscovery(self.CONF)
+        resources = dsc.discover(mock.MagicMock())
+        self.assertEqual(0, len(resources))