Avoid re-bootstrapping in workload's reconcile method

Author: shayancanonical

src/abstract_charm.py

@@ -135,7 +135,7 @@ def _substrate(self) -> str:
         """Returns the substrate of the charm: vm or k8s"""
 
     @abc.abstractmethod
-    def is_exposed(self, relation=None) -> bool:
+    def is_exposed(self, relation=None) -> typing.Optional[bool]:
         """Whether router is exposed externally"""
 
     def _cos_exporter_config(self, event) -> typing.Optional[relations.cos.ExporterConfig]:

src/machine_charm.py

@@ -100,7 +100,7 @@ def _tls_certificate(self) -> typing.Optional[str]:
     def _tls_certificate_authority(self) -> typing.Optional[str]:
         return self.tls.certificate_authority
 
-    def is_exposed(self, relation=None) -> bool:
+    def is_exposed(self, relation=None) -> typing.Optional[bool]:
         return self._database_provides.is_exposed
 
     def _reconcile_node_port(self, event) -> None:

src/workload.py

@@ -348,10 +348,7 @@ def reconcile(
         # If the host or port changes, MySQL Router will receive topology change
         # notifications from MySQL.
         # Therefore, if the host or port changes, we do not need to restart MySQL Router.
-        is_charm_exposed = self._charm.is_exposed()
-        socket_file_exists = self._container.path("/run/mysqlrouter/mysql.sock").exists()
-        require_rebootstrap = is_charm_exposed == socket_file_exists
-        if not self._container.mysql_router_service_enabled or require_rebootstrap:
+        if not self._container.mysql_router_service_enabled:
             logger.debug("Enabling MySQL Router service")
             self._cleanup_after_upgrade_or_potential_container_restart()
             # create an empty credentials file, if the file does not exist