Merge "rbd: Only log import failures when the RbdDriver is used"

nova/storage/rbd_utils.py

@@ -29,6 +29,12 @@ import nova.conf
 from nova import exception
 from nova.i18n import _
 
+try:
+    import rados
+    import rbd
+except ImportError:
+    rados = None
+    rbd = None
 
 CONF = nova.conf.CONF
 
@@ -36,25 +42,6 @@ LOG = logging.getLogger(__name__)
 
 RESIZE_SNAPSHOT_NAME = 'nova-resize'
 
-# NOTE(lyarwood): Log exceptions if we fail to import rbd or rados in order to
-# provide context later if we end up attempting to use the RbdDriver and
-# raising RuntimeError
-try:
-    import rados
-except ImportError:
-    rados = None
-    LOG.exception(
-        "Unable to import the rados module, this can be ignored if Ceph is "
-        "not used within this environment")
-
-try:
-    import rbd
-except ImportError:
-    rbd = None
-    LOG.exception(
-        "Unable to import the rbd module, this can be ignored if Ceph is not "
-        "used within this environment")
-
 
 class RbdProxy(object):
     """A wrapper around rbd.RBD class instance to avoid blocking of process.
@@ -137,8 +124,11 @@ class RBDDriver(object):
 
     def __init__(self, pool=None, user=None, ceph_conf=None,
                  connect_timeout=None):
-        if rbd is None:
-            raise RuntimeError(_('rbd python libraries not found'))
+
+        # NOTE(lyarwood): Ensure the rbd and rados modules have been imported
+        # correctly before continuing, this is done in a seperate private
+        # method to allow us to skip this check in unit tests etc.
+        self._check_for_import_failure()
 
         self.pool = pool or CONF.libvirt.images_rbd_pool
         self.rbd_user = user or CONF.libvirt.rbd_user
@@ -146,6 +136,23 @@ class RBDDriver(object):
             connect_timeout or CONF.libvirt.rbd_connect_timeout)
         self.ceph_conf = ceph_conf or CONF.libvirt.images_rbd_ceph_conf
 
+    def _check_for_import_failure(self):
+        # NOTE(lyarwood): If the original import of the required rbd or rados
+        # modules failed then repeat the imports at runtime within this driver
+        # to log the full exception in order to provide context to anyone
+        # debugging the failure in the logs.
+        global rados, rbd
+        if rbd is None or rados is None:
+            try:
+                # NOTE(lyarwood): noqa is required on both imports here as they
+                # are unused (F401) even if successful.
+                import rados  # noqa: F401
+                import rbd  # noqa: F401
+            except ImportError:
+                LOG.exception("Unable to import the rados or rbd modules")
+
+            raise RuntimeError(_('rbd python libraries not found'))
+
     def _connect_to_rados(self, pool=None):
         client = rados.Rados(rados_id=self.rbd_user,
                                   conffile=self.ceph_conf)

nova/tests/unit/image/test_glance.py

@@ -1337,9 +1337,11 @@ class TestRBDDownload(test.NoDBTestCase):
         self.pool_name = "images"
         self.snapshot_name = "snap"
 
+    @mock.patch('nova.storage.rbd_utils.RBDDriver._check_for_import_failure',
+                new=mock.Mock())
     @mock.patch.object(rbd_utils.RBDDriver, 'export_image')
-    @mock.patch.object(rbd_utils, 'rbd')
-    def test_rbd_download_success(self, mock_rbd, mock_export_image):
+    @mock.patch.object(rbd_utils, 'rbd', new=mock.Mock())
+    def test_rbd_download_success(self, mock_export_image):
         client = mock.MagicMock()
         ctx = mock.sentinel.ctx
         service = glance.GlanceImageServiceV2(client)
@@ -1366,9 +1368,11 @@ class TestRBDDownload(test.NoDBTestCase):
             exception.InvalidParameterValue, service.rbd_download, ctx,
             wrong_url_parts, mock.sentinel.dst_path)
 
+    @mock.patch('nova.storage.rbd_utils.RBDDriver._check_for_import_failure',
+                new=mock.Mock())
     @mock.patch('nova.storage.rbd_utils.RBDDriver.export_image')
-    @mock.patch.object(rbd_utils, 'rbd')
-    def test_rbd_download_export_failure(self, mock_rbd, mock_export_image):
+    @mock.patch.object(rbd_utils, 'rbd', new=mock.Mock())
+    def test_rbd_download_export_failure(self, mock_export_image):
         client = mock.MagicMock()
         ctx = mock.sentinel.ctx
         service = glance.GlanceImageServiceV2(client)

nova/tests/unit/virt/libvirt/test_driver.py

@@ -5350,10 +5350,12 @@ class LibvirtConnTestCase(test.NoDBTestCase,
     def test_get_guest_config_default_with_virtio_scsi_bus(self):
         self._test_get_guest_config_with_virtio_scsi_bus()
 
+    @mock.patch.object(rbd_utils.RBDDriver, '_check_for_import_failure',
+                       new=mock.Mock())
     @mock.patch.object(rbd_utils.RBDDriver, 'get_mon_addrs')
-    @mock.patch.object(rbd_utils, 'rbd')
+    @mock.patch.object(rbd_utils, 'rbd', new=mock.Mock())
     def test_get_guest_config_rbd_with_virtio_scsi_bus(
-            self, mock_rdb, mock_get_mon_addrs):
+            self, mock_get_mon_addrs):
         self.flags(images_type='rbd', group='libvirt')
         mock_get_mon_addrs.return_value = ("host", 9876)
         self._test_get_guest_config_with_virtio_scsi_bus()