Merge lp:~thedac/charm-helpers/expect-ha into lp:charm-helpers

[David Ames]

expect_ha function checks for VIP or dns-ha settings

In OpenStack charms that relate to hacluster it may take time for
hacluster to complete. In the meantime the charm needs a way to be
informed to wait for hacluster. Simply checking for the relation is
too racey. This function checks for tell tale configuration
parameters. The charm can then react accordingly.

Partial-bug: #1661392

[Liam Young (gnuoy)]

This fails lint and I think expect_ha could be simplified. I'll put up a mp based on this one so we can get the corresponding charm change landed asap

review: Needs Fixing

=== modified file 'charmhelpers/contrib/openstack/ha/utils.py'
--- charmhelpers/contrib/openstack/ha/utils.py	2016-07-06 14:41:05 +0000
+++ charmhelpers/contrib/openstack/ha/utils.py	2017-02-15 23:03:03 +0000
@@ -126,3 +126,16 @@
         status_set('blocked', msg)
         raise DNSHAException(msg)
     return True
+
+
+def expect_ha():
+    """ Determine if the unit expects to be in HA
+
+    Check for VIP or dns-ha settings which indicate the unit should expect to
+    be related to hacluster.
+
+    @returns boolean
+    """
+    if config('vip') or config('dns-ha'):
+        return True
+    return False

=== modified file 'tests/contrib/openstack/ha/test_ha_utils.py'
--- tests/contrib/openstack/ha/test_ha_utils.py	2016-06-17 20:10:31 +0000
+++ tests/contrib/openstack/ha/test_ha_utils.py	2017-02-15 23:03:03 +0000
@@ -113,3 +113,17 @@
         lsb_release.return_value = {'DISTRIB_RELEASE': '12.04'}
         self.assertRaises(ha.DNSHAException,
                           lambda: ha.assert_charm_supports_dns_ha())
+
+    def tests_expect_ha(self):
+        self.conf = {'vip': None,
+                     'dns-ha': None }
+        self.assertFalse(ha.expect_ha())
+
+        self.conf = {'vip': '10.0.0.1',
+                     'dns-ha': None}
+        self.assertTrue(ha.expect_ha())
+
+
+        self.conf = {'vip': None,
+                     'dns-ha': True}
+        self.assertTrue(ha.expect_ha())