Watch for config changed and gate on mons

Setup observer for config-changed events and get configuring the
dashboard on all the mons reporting ready.

Change-Id: I6a90d7afde2266e2dfa535d05e022a544914124a

src/charm.py

@@ -48,6 +48,9 @@ class CephDashboardCharm(ops_openstack.core.OSBaseCharm):
         """Setup adapters and observers."""
         super().__init__(*args)
         super().register_status_check(self.check_dashboard)
+        self.framework.observe(
+            self.on.config_changed,
+            self._configure_dashboard)
         self.mon = interface_dashboard.CephDashboardRequires(
             self,
             'dashboard')
@@ -112,6 +115,9 @@ class CephDashboardCharm(ops_openstack.core.OSBaseCharm):
 
     def _configure_dashboard(self, _) -> None:
         """Configure dashboard"""
+        if not self.mon.mons_ready:
+            logging.info("Not configuring dashboard, mons not ready")
+            return
         if self.unit.is_leader() and not ceph_utils.is_dashboard_enabled():
             ceph_utils.mgr_enable_dashboard()
         ceph_utils.mgr_config_set(

src/interface_dashboard.py

@@ -31,12 +31,23 @@ class CephDashboardRequires(Object):
             charm.on[relation_name].relation_changed,
             self.on_changed)
 
+    @property
+    def mons_ready(self) -> bool:
+        """Check that all mons have reported ready."""
+        ready = False
+        if self.dashboard_relation:
+            # There will only be one unit as this is a subordinate relation.
+            for unit in self.dashboard_relation.units:
+                unit_data = self.dashboard_relation.data[unit]
+                if unit_data.get(self.READY_KEY) == 'True':
+                    ready = True
+        return ready
+
     def on_changed(self, event):
+        """Emit mon_ready if mons are ready."""
         logging.debug("CephDashboardRequires on_changed")
-        for u in self.dashboard_relation.units:
-            if self.dashboard_relation.data[u].get(self.READY_KEY) == 'True':
-                logging.debug("Emitting mon ready")
-                self.on.mon_ready.emit()
+        if self.mons_ready:
+            self.on.mon_ready.emit()
 
     @property
     def dashboard_relation(self):

tests/bundles/focal.yaml

@@ -9,7 +9,7 @@ applications:
     options:
       osd-devices: '/dev/test-non-existent'
   ceph-mon:
-    charm: cs:~gnuoy/ceph-mon-26
+    charm: cs:~openstack-charmers-next/ceph-mon
     num_units: 3
     options:
       monitor-count: '3'

unit_tests/test_ceph_dashboard_charm.py

@@ -239,9 +239,19 @@ class TestCephDashboardCharmBase(CharmTestCase):
         self.ceph_utils.mgr_enable_dashboard.assert_called_once_with()
 
     def test__configure_dashboard(self):
-        self.harness.begin()
-
         self.ceph_utils.is_dashboard_enabled.return_value = True
+        rel_id = self.harness.add_relation('dashboard', 'ceph-mon')
+        self.harness.begin()
+        self.harness.add_relation_unit(
+            rel_id,
+            'ceph-mon/0')
+        self.harness.update_relation_data(
+            rel_id,
+            'ceph-mon/0',
+            {
+                'mon-ready': 'True'})
+
+        self.ceph_utils.mgr_config_set.reset_mock()
         self.harness.set_leader(False)
         self.harness.charm._configure_dashboard(None)
         self.assertFalse(self.ceph_utils.mgr_enable_dashboard.called)

unit_tests/test_interface_dashboard.py

@@ -96,3 +96,26 @@ class TestCephDashboardRequires(unittest.TestCase):
         self.assertEqual(
             self.harness.charm.seen_events,
             ['MonReadyEvent'])
+        self.assertTrue(
+            self.harness.charm.mon.mons_ready)
+
+    def test_on_changed_not_ready_unit(self):
+        self.harness.begin()
+        # No MonReadyEvent as relation is absent
+        self.assertEqual(
+            self.harness.charm.seen_events,
+            [])
+        rel_id = self.add_dashboard_relation()
+        # No MonReadyEvent as ceph-mon has not declared it is ready.
+        self.assertEqual(
+            self.harness.charm.seen_events,
+            [])
+        self.harness.update_relation_data(
+            rel_id,
+            'ceph-mon/0',
+            {})
+        self.assertEqual(
+            self.harness.charm.seen_events,
+            [])
+        self.assertFalse(
+            self.harness.charm.mon.mons_ready)