fix: go into blocked status if MetalLB is not enabled and N2 relation is set

src/charm.py

@@ -214,7 +214,11 @@ def _configure_amf(self, event: EventBase) -> None:  # noqa C901
             return
         self._generate_config_file()
         self._configure_amf_workload()
-        self._set_n2_information()
+        try:
+            self._set_n2_information()
+        except ValueError:
+            self.unit.status = BlockedStatus("Waiting for MetalLB to be enabled")
+            return
         self.unit.status = ActiveStatus()
 
     def _on_certificates_relation_created(self, event: EventBase) -> None:
@@ -386,16 +390,20 @@ def _on_n2_relation_joined(self, event: RelationJoinedEvent) -> None:
         Args:
             event (RelationJoinedEvent): Juju event
         """
-        self._set_n2_information()
+        try:
+            self._set_n2_information()
+        except ValueError:
+            self.unit.status = BlockedStatus("Waiting for MetalLB to be enabled")
+            return
 
-    def _get_n2_amf_ip(self) -> str:
+    def _get_n2_amf_ip(self) -> Optional[str]:
         """Returns the IP to send for the N2 interface.
 
         If a configuration is provided, it is returned, otherwise
         returns the IP of the external LoadBalancer Service.
 
         Returns:
-            str: IP address of the AMF
+            str/None: IP address of the AMF if available else None
         """
         if configured_ip := self._get_external_amf_ip_config():
             return configured_ip
@@ -634,45 +642,45 @@ def _amf_service_is_running(self) -> bool:
             return False
         return service.is_running()
 
-    def _amf_external_service_ip(self) -> str:
+    def _amf_external_service_ip(self) -> Optional[str]:
         """Returns the external service IP.
 
         Returns:
-            str: External Service IP
+            str/None: External Service IP if available else None
         """
         client = Client()
         service = client.get(
             Service, name=f"{self.model.app.name}-external", namespace=self.model.name
         )
         try:
             return service.status.loadBalancer.ingress[0].ip  # type: ignore[attr-defined]
-        except AttributeError:
+        except (AttributeError, TypeError):
             logger.error(
                 "Service '%s-external' does not have an IP address:\n%s",
                 self.model.app.name,
                 service,
             )
-            return ""
+            return None
 
-    def _amf_external_service_hostname(self) -> str:
+    def _amf_external_service_hostname(self) -> Optional[str]:
         """Returns the external service hostname.
 
         Returns:
-            str: External Service hostname
+            str: External Service hostname if available else None
         """
         client = Client()
         service = client.get(
             Service, name=f"{self.model.app.name}-external", namespace=self.model.name
         )
         try:
             return service.status.loadBalancer.ingress[0].hostname  # type: ignore[attr-defined]
-        except AttributeError:
+        except (AttributeError, TypeError):
             logger.error(
                 "Service '%s-external' does not have a hostname:\n%s",
                 self.model.app.name,
                 service,
             )
-            return ""
+            return None
 
 
 def _get_pod_ip() -> Optional[str]:

tests/unit/test_charm.py

@@ -666,6 +666,47 @@ def test_given_n2_information_and_service_is_running_and_lb_service_has_no_hostn
         )
         self.assertEqual(relation_data["amf_port"], "38412")
 
+    @patch("lightkube.core.client.GenericSyncClient", new=Mock)
+    @patch("lightkube.core.client.Client.get")
+    @patch("ops.model.Container.pull")
+    @patch("ops.model.Container.exists")
+    @patch("ops.model.Container.push")
+    @patch("charm.check_output")
+    @patch("charms.sdcore_nrf.v0.fiveg_nrf.NRFRequires.nrf_url", new_callable=PropertyMock)
+    @patch("charms.data_platform_libs.v0.data_interfaces.DatabaseRequires.is_resource_created")
+    def test_given_n2_information_and_service_is_running_and_metallb_service_is_not_available_when_fiveg_n2_relation_joined_then_amf_goes_in_blocked_state(  # noqa: E501
+        self,
+        patch_is_resource_created,
+        patch_nrf_url,
+        patch_check_output,
+        patch_push,
+        patch_exists,
+        patch_pull,
+        patch_get,
+    ):
+        patch_pull.return_value = StringIO(
+            self._read_file("tests/unit/expected_config/config.conf").strip()
+        )
+        patch_exists.return_value = True
+        patch_check_output.return_value = b"1.1.1.1"
+        service = Mock(status=Mock(loadBalancer=Mock(ingress=None)))
+        patch_get.return_value = service
+        patch_exists.return_value = True
+        patch_is_resource_created.return_value = True
+        patch_nrf_url.return_value = "http://nrf:8081"
+        self.harness.set_can_connect(container="amf", val=True)
+        self.harness.add_relation(relation_name="fiveg-nrf", remote_app="nrf")
+        self.harness.add_relation(
+            relation_name="certificates", remote_app="tls-certificates-operator"
+        )
+        self._database_is_available()
+        self.harness.container_pebble_ready("amf")
+        relation_id = self.harness.add_relation(relation_name="fiveg-n2", remote_app="n2-requirer")
+        self.harness.add_relation_unit(relation_id=relation_id, remote_unit_name="n2-requirer/0")
+        self.assertEqual(
+            self.harness.charm.unit.status, BlockedStatus("Waiting for MetalLB to be enabled")
+        )
+
     @patch("lightkube.core.client.GenericSyncClient", new=Mock)
     @patch("lightkube.core.client.Client.get")
     @patch("ops.model.Container.pull")