Raise a shade exception on broken volumes

Some clouds don't have volumes and bomb out here, which is a bad place
to bomb out. A later patch will add an active check for service
existence, but we still should catch and throw here so that we're not
leaking python-*client exceptions.

Change-Id: I1f768dcd6ad6f54fb1b5638e9486653ee07965ef

shade/__init__.py

@@ -839,9 +839,16 @@ class OpenStackCloud(object):
         if not cache:
             warnings.warn('cache argument to list_volumes is deprecated. Use '
                           'invalidate instead.')
-        return meta.obj_list_to_dict(
-            self.manager.submitTask(_tasks.VolumeList())
-        )
+        try:
+            return meta.obj_list_to_dict(
+                self.manager.submitTask(_tasks.VolumeList())
+            )
+        except Exception as e:
+            self.log.debug(
+                "cinder could not list volumes: {message}".format(
+                    message=str(e)),
+                exc_info=True)
+            raise OpenStackCloudException("Error fetching volume list")
 
     @_cache_on_arguments()
     def list_flavors(self):

shade/meta.py

@@ -15,6 +15,8 @@
 
 import six
 
+from shade import exc
+
 NON_CALLABLES = (six.string_types, bool, dict, int, list, type(None))
 
 
@@ -126,10 +128,13 @@ def get_hostvars_from_server(cloud, server, mounts=None):
     server_vars['image'].pop('links', None)
 
     volumes = []
-    for volume in cloud.get_volumes(server):
-        # Make things easier to consume elsewhere
-        volume['device'] = volume['attachments'][0]['device']
-        volumes.append(volume)
+    try:
+        for volume in cloud.get_volumes(server):
+            # Make things easier to consume elsewhere
+            volume['device'] = volume['attachments'][0]['device']
+            volumes.append(volume)
+    except exc.OpenStackCloudException:
+        pass
     server_vars['volumes'] = volumes
     if mounts:
         for mount in mounts: