Fix image/tasks API for in-progress tasks

A slight error in the tasks_get_by_image() DB API method resulted in
our excluding in-progress tasks from the returned list. This is
because those tasks have expires_at=NULL, and we were comparing
the expires_at>=$NOW to find unexpired tasks. This makes us check for
"NULL or not expired" instead.

We did have a test asserting the wrong behavior, but it was done to
increase coverage and thus was asserting the behavior of the code and
not the *desired* behavior. This fixes that as well.

Closes-Bug: #1922928
Change-Id: I1b6971888673b64ef60bed8fbcc97bbcbcf5c2ac
(cherry picked from commit 2a0d230)

Author: kk7ds

glance/db/sqlalchemy/api.py

@@ -1672,7 +1672,8 @@ def tasks_get_by_image(context, image_id, session=None):
     ).filter_by(image_id=image_id)
 
     expires_at = models.Task.expires_at
-    query = query.filter(expires_at >= timeutils.utcnow())
+    query = query.filter(sa_sql.or_(expires_at == None,
+                                    expires_at >= timeutils.utcnow()))
     updated_at = models.Task.updated_at
     query.filter(
         updated_at <= (timeutils.utcnow() +

glance/tests/functional/db/base.py

@@ -1774,13 +1774,13 @@ def test_task_get_by_image_expired(self):
         self.assertTrue(tasks[0]['deleted'])
 
     def test_task_get_by_image_no_expiry(self):
-        # Make sure we do not retrieve the expired task
+        # Make sure we find the task that has expires_at=NULL
         task_id, tasks = self._test_task_get_by_image(expired=None)
-        self.assertEqual(0, len(tasks))
+        self.assertEqual(1, len(tasks))
 
-        # The task should not have been retrieved at all above,
-        # but it's also not deleted because it doesn't have an expiry,
-        # so it should still be in the DB.
+        # The task should have been retrieved above, and it's also not
+        # deleted because it doesn't have an expiry, so it should
+        # still be in the DB.
         tasks = self.db_api.task_get_all(self.adm_context)
         self.assertEqual(1, len(tasks))
         self.assertEqual(task_id, tasks[0]['id'])