Ensure we don't ask a backend store to delete an image if the image is queued or saving.

glance/server.py

@@ -450,7 +450,12 @@ class Controller(wsgi.Controller):
         """
         image = self.get_image_meta_or_404(req, id)
 
-        delete_from_backend(image['location'])
+        # The image's location field may be None in the case
+        # of a saving or queued image, therefore don't ask a backend
+        # to delete the image if the backend doesn't yet store it.
+        # See https://bugs.launchpad.net/glance/+bug/747799
+        if image['location']:
+            delete_from_backend(image['location'])
 
         registry.delete_image_metadata(self.options, id)
 

tests/stubs.py

@@ -321,6 +321,7 @@ def stub_out_registry_db_image_api(stubs):
             values['checksum'] = values.get('checksum')
             values['deleted'] = False
             values['properties'] = values.get('properties', {})
+            values['location'] = values.get('location')
             values['created_at'] = datetime.datetime.utcnow()
             values['updated_at'] = datetime.datetime.utcnow()
             values['deleted_at'] = None

tests/unit/test_api.py

@@ -582,3 +582,35 @@ class TestGlanceAPI(unittest.TestCase):
         req.method = 'DELETE'
         res = req.get_response(self.api)
         self.assertEquals(res.status_int, webob.exc.HTTPNotFound.code)
+
+    def test_delete_queued_image(self):
+        """
+        Here, we try to delete an image that is in the queued state.
+        Bug #747799 demonstrated that trying to DELETE an image
+        that had had its save process killed manually results in failure
+        because the location attribute is None.
+        """
+        # Add an image the way that glance-upload adds an image...
+        # by reserving a place in the database for an image without
+        # really any attributes or information on the image and then
+        # later doing an update with the image body and other attributes.
+        # We will stop the process after the reservation stage, then
+        # try to delete the image.
+        fixture_headers = {'x-image-meta-store': 'file',
+                           'x-image-meta-name': 'fake image #3'}
+
+        req = webob.Request.blank("/images")
+        req.method = 'POST'
+        for k, v in fixture_headers.iteritems():
+            req.headers[k] = v
+        res = req.get_response(self.api)
+        self.assertEquals(res.status_int, httplib.CREATED)
+
+        res_body = json.loads(res.body)['image']
+        self.assertEquals('queued', res_body['status'])
+
+        # Now try to delete the image...
+        req = webob.Request.blank("/images/3")
+        req.method = 'DELETE'
+        res = req.get_response(self.api)
+        self.assertEquals(res.status_int, 200)