Do not pause manila-share during upgrades

The upgrade-charm hook calls install() which by default will pause
manila-share if there are peer units. We cant do this on upgrade as it
will block active shares and never be resumed.

Closes-Bug: #2111818
Change-Id: I982e60e4ddbbdd92d8e471318408bb29394e04a3
Signed-off-by: Edward Hope-Morley <edward.hope-morley@canonical.com>
Signed-off-by: Nicolas Bock <nicolas.bock@canonical.com>

src/lib/charm/openstack/manila_ganesha.py

@@ -23,6 +23,7 @@ import charms_openstack.adapters
 import charms_openstack.plugins
 import charms_openstack.charm.utils
 import charmhelpers.contrib.network.ip as ch_net_ip
+import charms.reactive as reactive
 import charms.reactive.relations as relations
 from charmhelpers.core.host import (
     cmp_pkgrevno,
@@ -302,10 +303,20 @@ class ManilaGaneshaCharm(charms_openstack.charm.HAOpenStackCharm,
         _goal_state = goal_state()
         peers = (key for key in _goal_state['units']
                  if '/' in key and key != local_unit())
-        if len(list(peers)) > 0:
+        if (not reactive.is_flag_set('is-upgrade-charm') and
+                len(list(peers)) > 0):
             service_pause('manila-share')
+
         super().install()
 
+    def upgrade_charm(self):
+        """ Override the default so we can set a flag before it runs. """
+        reactive.set_flag('is-upgrade-charm')
+        try:
+            super().upgrade_charm()
+        finally:
+            reactive.clear_flag('is-upgrade-charm')
+
     def service_restart(self, service_name):
         res_name = self.service_to_resource_map.get(service_name, None)
         if not res_name or not peer_units():

src/reactive/manila_ganesha.py

@@ -22,8 +22,7 @@ charm.use_defaults(
     'shared-db.connected',
     'config.changed',
     'update-status',
-    'upgrade-charm',
+    # TODO: remove following commented out code.
-    # TODO: remove follwoing commented out code.
     # remove certificates.available as we want to wire in the call ourselves
     # directly.
     # 'certificates.available',