Skip version caching for subordinate charms

Caching the charm OpenStack version will cause undesired behaviors
if the charm is a subordinate. The charm local cache is firstly
populated during the charm install. If the charm is a subordinate,
the version will remain the same regardless of future OpenStack
upgrades because today, the hook that updates the cache to the new
version in only called for principal charms.

Related-bug: #1949074
Change-Id: I76abbd29ca910fe4c4d62da09e2d2dd3b5c798a6

charms_openstack/charm/defaults.py

@@ -1,4 +1,5 @@
 import charmhelpers.contrib.openstack.utils as os_utils
+import charmhelpers.core.hookenv as hookenv
 import charmhelpers.core.unitdata as unitdata
 import charms.reactive as reactive
 
@@ -97,7 +98,15 @@ def make_default_select_release_handler():
         that it doesn't need to keep going and getting it from the package
         information.
         """
-        release_version = unitdata.kv().get(OPENSTACK_RELEASE_KEY, None)
+        release_version = None
+        # Using the cached OpenStack version will cause undesired behaviors
+        # if the charm is a subordinate. The charm local cache is firstly
+        # populated during the charm install and after that, only during the
+        # openstack upgrades. If the charm is a subordinate, the version will
+        # always remain the same.
+        if not hookenv.is_subordinate():
+            release_version = unitdata.kv().get(OPENSTACK_RELEASE_KEY, None)
+
         if release_version is None:
             try:
                 # First make an attempt of determining release from a charm
@@ -125,7 +134,11 @@ def make_default_select_release_handler():
                     pkg = 'dummy-package'
                 release_version = os_utils.os_release(
                     pkg, source_key=singleton.source_config_key)
-            unitdata.kv().set(OPENSTACK_RELEASE_KEY, release_version)
+
+            # Skip caching the release if the charm is a subordinate.
+            if not hookenv.is_subordinate():
+                unitdata.kv().set(OPENSTACK_RELEASE_KEY, release_version)
+
         return release_version
 
 

unit_tests/charms_openstack/charm/test_defaults.py

@@ -113,6 +113,7 @@ class TestDefaults(BaseOpenStackCharmTest):
         singleton.source_config_key = 'fake-config-key'
         singleton.get_os_codename_package.return_value = None
         self.patch_object(chm, 'get_charm_instance', return_value=singleton)
+        self.patch_object(chm.hookenv, 'is_subordinate', return_value=False)
         # set a release
         kv.get.return_value = 'one'
         release = h.map['function']()
@@ -153,6 +154,19 @@ class TestDefaults(BaseOpenStackCharmTest):
         self.assertEqual(release, 'four')
         singleton.get_os_codename_package.assert_called_once_with(
             mock.ANY, mock.ANY, apt_cache_sufficient=True)
+        # Test subordinate charm
+        kv.reset_mock()
+        kv.get.return_value = None
+        singleton.get_os_codename_package.reset_mock()
+        singleton.get_os_codename_package.return_value = 'five'
+        chm.hookenv.is_subordinate.reset_mock()
+        chm.hookenv.is_subordinate.return_value = True
+        self.os_release.reset_mock()
+        self.os_release.return_value = 'five'
+        release = h.map['function']()
+        self.assertEqual(release, 'five')
+        kv.set.assert_not_called()
+        kv.get.assert_not_called()
 
     def test_default_select_package_type_handler(self):
         self.assertIn('charm.default-select-package-type',