Series Upgrade

Implement the series-upgrade feature allowing to move between Ubuntu
series.

Change-Id: I68ba3ac518406c61ba1a6c61fd3236a0d8cb5d16

src/reactive/vault_handlers.py

@@ -584,6 +584,12 @@ def _assess_status():
                    'vip and dns-ha-access-record configured')
         return
 
+    if unitdata.kv().get('charm.vault.series-upgrading'):
+        status_set("blocked",
+                   "Ready for do-release-upgrade and reboot. "
+                   "Set complete when finished.")
+        return
+
     health = None
     if service_running('vault'):
         health = vault.get_vault_health()
@@ -721,3 +727,19 @@ def create_certs():
             log(str(e), level=ERROR)
             continue  # TODO: report failure back to client
     clear_flag('certificates.reissue.requested')
+
+
+# Series upgrade hooks are a special case and reacting to the hook directly
+# makes sense as we may not want other charm code to run
+@hook('pre-series-upgrade')
+def pre_series_upgrade():
+    """Handler for pre-series-upgrade.
+    """
+    unitdata.kv().set('charm.vault.series-upgrading', True)
+
+
+@hook('post-series-upgrade')
+def post_series_upgrade():
+    """Handler for post-series-upgrade.
+    """
+    unitdata.kv().set('charm.vault.series-upgrading', False)

unit_tests/test_reactive_vault_handlers.py

@@ -74,6 +74,9 @@ class TestHandlers(unit_tests.test_utils.CharmTestCase):
         ]
         self.patch_all()
         self.is_container.return_value = False
+        self.kv = mock.MagicMock()
+        self.kv.get.return_value = False
+        self.unitdata.kv.return_value = self.kv
 
     def test_ssl_available(self):
         self.assertFalse(handlers.ssl_available({
@@ -563,8 +566,8 @@ class TestHandlers(unit_tests.test_utils.CharmTestCase):
         hvac_client.auth_approle.assert_called_once_with('local-approle')
         _vault.configure_secret_backend.assert_has_calls([
             mock.call(hvac_client, name='charm-vaultlocker'),
-            mock.call(hvac_client, name='charm-supersecrets')
-        ])
+            mock.call(hvac_client, name='charm-supersecrets'),
+        ], any_order=True)
 
         _vault.configure_policy.assert_has_calls([
             mock.call(hvac_client, name='charm-ceph-osd-0', hcl=mock.ANY),