Fix drbd driver to load without 3'rd party libs

The new drbd driver has a couple needed 3'rd party libs
that aren't in the global requirements.  That means that
any time there's an attempt to import the driver things
blow up due to import errors.

The great thing is that the author took care of things in
unit tests by creating mocks, but we still have the problem
of the driver itself, and this causes us to be unable to do
things like genconfig.

This patch just wraps the 3'rd party libs into a try/catch
block, sets them to None if they're not on the system.

Also, move the global dbus.array variable into init and
make it a member variable.

Change-Id: I33b605fecf1709efa6124312ba58cd29ed885178
Closes-Bug: #1408483

diff --git a/cinder/volume/drivers/drbdmanagedrv.py b/cinder/volume/drivers/drbdmanagedrv.py
index 6221744e4d6fc23c599ff01bd17f22a56fa0c579..ed27fecce91438ffcfa93d2f633533eb23416400 100644 (file)
--- a/cinder/volume/drivers/drbdmanagedrv.py
+++ b/cinder/volume/drivers/drbdmanagedrv.py
@@ -25,10 +25,6 @@ for more details.
 
 import uuid
 
-import dbus
-import drbdmanage.consts as dm_const
-import drbdmanage.exceptions as dm_exc
-import drbdmanage.utils as dm_utils
 from oslo.config import cfg
 from oslo.utils import importutils
 from oslo.utils import units
@@ -40,9 +36,19 @@ from cinder.i18n import _, _LW
 from cinder.openstack.common import log as logging
 from cinder.volume import driver
 
+try:
+    import dbus
+    import drbdmanage.consts as dm_const
+    import drbdmanage.exceptions as dm_exc
+    import drbdmanage.utils as dm_utils
+except ImportError:
+    dbus = None
+    dm_const = None
+    dm_exc = None
+    dm_utils = None
+
 
 LOG = logging.getLogger(__name__)
-EMPTY_LIST = dbus.Array([], signature="a(ss)")
 
 drbd_opts = [
     cfg.StrOpt('drbdmanage_redundancy',
@@ -70,6 +76,7 @@ class DrbdManageDriver(driver.VolumeDriver):
     drbdmanage_dbus_interface = '/interface'
 
     def __init__(self, execute=None, *args, **kwargs):
+        self.empty_list = dbus.Array([], signature="a(ss)")
         super(DrbdManageDriver, self).__init__(*args, **kwargs)
         if self.configuration:
             self.configuration.append_config_values(drbd_opts)
@@ -200,11 +207,11 @@ class DrbdManageDriver(driver.VolumeDriver):
             v_uuid = volume['id']
 
         res, rl = self.call_or_reconnect(self.odm.list_volumes,
-                                         EMPTY_LIST,
+                                         self.empty_list,
                                          0,
                                          dm_utils.dict_to_aux_props(
                                              {CINDER_AUX_PROP_id: v_uuid}),
-                                         EMPTY_LIST)
+                                         self.empty_list)
         self._check_result(res)
 
         if (not rl) or (len(rl) == 0):
@@ -237,11 +244,11 @@ class DrbdManageDriver(driver.VolumeDriver):
         """
         s_uuid = snapshot['id']
         res, rs = self.call_or_reconnect(self.odm.list_snapshots,
-                                         EMPTY_LIST,
-                                         EMPTY_LIST,
+                                         self.empty_list,
+                                         self.empty_list,
                                          dm_utils.dict_to_aux_props(
                                              {CINDER_AUX_PROP_id: s_uuid}),
-                                         EMPTY_LIST)
+                                         self.empty_list)
         self._check_result(res)
 
         if (not rs) or (len(rs) == 0):
@@ -296,7 +303,7 @@ class DrbdManageDriver(driver.VolumeDriver):
         LOG.debug("create vol: make %s" % dres)
         res = self.call_or_reconnect(self.odm.create_resource,
                                      dres,
-                                     EMPTY_LIST)
+                                     self.empty_list)
         exist = self._check_result(res, ignore=[dm_exc.DM_EEXIST], ret=None)
         if exist == dm_exc.DM_EEXIST:
             # Volume already exists, eg. because deploy gave an error
@@ -345,7 +352,7 @@ class DrbdManageDriver(driver.VolumeDriver):
 
         new_res = self.is_clean_volume_name(volume['id'])
 
-        r_props = EMPTY_LIST
+        r_props = self.empty_list
         v_props = self._priv_hash_from_volume(volume)
 
         res = self.call_or_reconnect(self.odm.restore_snapshot,
@@ -434,11 +441,11 @@ class DrbdManageDriver(driver.VolumeDriver):
             snapshot["volume_id"])
 
         res, data = self.call_or_reconnect(self.odm.list_assignments,
-                                           EMPTY_LIST,
+                                           self.empty_list,
                                            [dres],
                                            0,
-                                           EMPTY_LIST,
-                                           EMPTY_LIST)
+                                           self.empty_list,
+                                           self.empty_list)
         self._check_result(res)
 
         nodes = map(lambda d: d[0], data)