Merge lp:~stub/charms/trusty/cassandra/bug-1555261-fix-null-username into lp:charms/trusty/cassandra

[Stuart Bishop]

Fix Bug #1555261, where we could generate usernames such as 'juju_None'.

A race condition exists such that the remote service name may be unknown in the client relation-joined and relation-changed hooks. In this case, we should do nothing and wait until related units actually exist in a future relation-changed hook.

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This item has failed automated testing! Results available here http://juju-ci.vapour.ws:8080/job/charm-bundle-test-aws/3657/

review: Needs Fixing (automated testing)

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This item has failed automated testing! Results available here http://juju-ci.vapour.ws:8080/job/charm-bundle-test-lxc/3604/

review: Needs Fixing (automated testing)

[Stuart Bishop (stub)]

Now in the charmstore

=== modified file 'hooks/actions.py'
--- hooks/actions.py	2016-03-17 10:54:10 +0000
+++ hooks/actions.py	2016-04-12 07:35:55 +0000
@@ -663,6 +663,12 @@
             # even after the relation is dropped and recreated, or the
             # juju environment rebuild and the database restored from
             # backups.
+            service_name = helpers.get_service_name(relid)
+            if not service_name:
+                # Per Bug #1555261, we might not yet have related units,
+                # so no way to calculate the remote service name and thus
+                # the user.
+                return  # Try again later.
             username = 'juju_{}'.format(helpers.get_service_name(relid))
             if superuser:
                 username += '_admin'