Fixed deleting instance booted from invalid vol

1. Translated the exception (NotFound) raised from Cinder client to
Nova's native exception (VolumeNotFound).
2. Added unit test coverage.

Fixes LP: #1087214.

Change-Id: I3cee31a9fd068b65a4097f3f3054aebb69d9ba61
(cherry picked from commit 921eec91ab)

nova/tests/test_cinder.py

@@ -17,7 +17,9 @@
 import httplib2
 import urlparse
 
+from cinderclient import exceptions as cinder_exception
 from nova import context
+from nova import exception
 from nova.volume import cinder
 
 from nova import test
@@ -77,6 +79,9 @@ class FakeHTTPClient(cinder.cinder_client.client.HTTPClient):
         volume = {'volume': _stub_volume(id='1234')}
         return (200, volume)
 
+    def get_volumes_nonexisting(self, **kw):
+        raise cinder_exception.NotFound(code=404, message='Resource not found')
+
 
 class FakeCinderClient(cinder.cinder_client.Client):
 
@@ -149,3 +154,7 @@ class CinderTestCase(test.TestCase):
         self.assertEquals(
             self.fake_client_factory.client.client.management_url,
             'http://other_host:8776/v1/project_id')
+
+    def test_get_non_existing_volume(self):
+        self.assertRaises(exception.VolumeNotFound, self.api.get, self.context,
+                          'nonexisting')

nova/volume/cinder.py

@@ -20,7 +20,9 @@
 Handles all requests relating to volumes + cinder.
 """
 
+import sys
 
+from cinderclient import exceptions as cinder_exception
 from cinderclient import service_catalog
 from cinderclient.v1 import client as cinder_client
 
@@ -140,9 +142,24 @@ def _untranslate_snapshot_summary_view(context, snapshot):
 class API(base.Base):
     """API for interacting with the volume manager."""
 
+    def _reraise_translated_volume_exception(self, volume_id):
+        """Transform the exception for the volume but keep its traceback
+        intact."""
+        exc_type, exc_value, exc_trace = sys.exc_info()
+        new_exc = self._translate_volume_exception(volume_id, exc_value)
+        raise new_exc, None, exc_trace
+
+    def _translate_volume_exception(self, volume_id, exc_value):
+        if isinstance(exc_value, cinder_exception.NotFound):
+            return exception.VolumeNotFound(volume_id=volume_id)
+        return exc_value
+
     def get(self, context, volume_id):
-        item = cinderclient(context).volumes.get(volume_id)
-        return _untranslate_volume_summary_view(context, item)
+        try:
+            item = cinderclient(context).volumes.get(volume_id)
+            return _untranslate_volume_summary_view(context, item)
+        except Exception:
+            self._reraise_translated_volume_exception(volume_id)
 
     def get_all(self, context, search_opts={}):
         items = cinderclient(context).volumes.list(detailed=True)