Updates status determination so that logic from upstream instead uses

thing single method.

src/charm.py

@@ -38,7 +38,7 @@ def __init__(self, *args):
             self.on.dbcluster_relation_changed, self._on_dbcluster_relation_changed)
 
         self.control_socket = controlsocket.Client(
-            socket_path="/var/lib/juju/control.socket")
+            socket_path='/var/lib/juju/control.socket')
         self.framework.observe(
             self.on.metrics_endpoint_relation_created, self._on_metrics_endpoint_relation_created)
         self.framework.observe(
@@ -49,9 +49,11 @@ def _on_collect_status(self, event: CollectStatusEvent):
             event.add_status(BlockedStatus(
                 'multiple possible DB bind addresses; set a suitable dbcluster network binding'))
 
-        if self.api_port() is None:
-            event.add_status(BlockedStatus(
-                'charm does not appear to be running on a controller node'))
+        try:
+            self.api_port()
+        except AgentConfException as e:
+            event.add_status(ErrorStatus(
+                f"cannot read controller API port from agent configuration: {e}"))
 
         event.add_status(ActiveStatus())
 
@@ -73,9 +75,11 @@ def _on_dashboard_relation_joined(self, event):
     def _on_website_relation_joined(self, event):
         """Connect a website relation."""
         logger.info('got a new website relation: %r', event)
-        port = self.api_port()
-        if port is None:
-            logger.error('charm does not appear to be running on a controller node')
+
+        try:
+            api_port = self.api_port()
+        except AgentConfException as e:
+            logger.error("cannot read controller API port from agent configuration: {}", e)
             return
 
         address = None
@@ -86,7 +90,7 @@ def _on_website_relation_joined(self, event):
                 event.relation.data[self.unit].update({
                     'hostname': str(address),
                     'private-address': str(address),
-                    'port': str(port)
+                    'port': str(api_port)
                 })
 
     def _on_metrics_endpoint_relation_created(self, event: RelationJoinedEvent):
@@ -98,7 +102,7 @@ def _on_metrics_endpoint_relation_created(self, event: RelationJoinedEvent):
         try:
             api_port = self.api_port()
         except AgentConfException as e:
-            self.unit.status = ErrorStatus(f"can't read controller API port from agent.conf: {e}")
+            logger.error("cannot read controller API port from agent configuration: {}", e)
             return
 
         metrics_endpoint = MetricsEndpointProvider(
@@ -143,15 +147,6 @@ def _on_dbcluster_relation_changed(self, event):
         self._stored.db_bind_address = ip
         event.relation.data[self.unit].update({'db-bind-address': ip})
 
-    def _agent_conf(self, key: str):
-        """Read a value (by key) from the agent.conf file on disk."""
-        unit_name = self.unit.name.replace('/', '-')
-        agent_conf_path = f'/var/lib/juju/agents/unit-{unit_name}/agent.conf'
-
-        with open(agent_conf_path) as agent_conf_file:
-            agent_conf = yaml.safe_load(agent_conf_file)
-            return agent_conf.get(key)
-
     def api_port(self) -> str:
         """Return the port on which the controller API server is listening."""
         api_addresses = self._agent_conf('apiaddresses')
@@ -162,13 +157,22 @@ def api_port(self) -> str:
 
         parsed_url = urllib.parse.urlsplit('//' + api_addresses[0])
         if not parsed_url.port:
-            raise AgentConfException("api address doesn't include port")
+            raise AgentConfException("API address does not include port")
         return parsed_url.port
 
     def ca_cert(self) -> str:
         """Return the controller's CA certificate."""
         return self._agent_conf('cacert')
 
+    def _agent_conf(self, key: str):
+        """Read a value (by key) from the agent.conf file on disk."""
+        unit_name = self.unit.name.replace('/', '-')
+        agent_conf_path = f'/var/lib/juju/agents/unit-{unit_name}/agent.conf'
+
+        with open(agent_conf_path) as agent_conf_file:
+            agent_conf = yaml.safe_load(agent_conf_file)
+            return agent_conf.get(key)
+
 
 def metrics_username(relation: Relation) -> str:
     """

tests/test_charm.py

@@ -4,8 +4,7 @@
 import os
 import unittest
 from charm import JujuControllerCharm, AgentConfException
-from ops.model import BlockedStatus, ActiveStatus
-from ops import ErrorStatus
+from ops.model import BlockedStatus, ActiveStatus, ErrorStatus
 from ops.testing import Harness
 from unittest.mock import mock_open, patch
 
@@ -140,9 +139,8 @@ def test_apiaddresses_missing_status(self, *_):
         harness.begin()
 
         harness.add_relation('metrics-endpoint', 'prometheus-k8s')
-        self.assertEqual(harness.charm.unit.status, ErrorStatus(
-            "can't read controller API port from agent.conf: agent.conf key 'apiaddresses' missing"
-        ))
+        harness.evaluate_status()
+        self.assertIsInstance(harness.charm.unit.status, ErrorStatus)
 
     @patch("builtins.open", new_callable=mock_open, read_data=agent_conf_ipv4)
     def test_apiaddresses_ipv4(self, _):