DPE-3879 update endpoint on upgrade

src/mysql_vm_helpers.py

@@ -9,6 +9,7 @@
 import shutil
 import subprocess
 import tempfile
+import typing
 from typing import Dict, List, Optional, Tuple
 
 import jinja2
@@ -26,7 +27,6 @@
     MySQLStopMySQLDError,
 )
 from charms.operator_libs_linux.v2 import snap
-from ops.charm import CharmBase
 from tenacity import RetryError, Retrying, retry, stop_after_attempt, stop_after_delay, wait_fixed
 from typing_extensions import override
 
@@ -53,6 +53,9 @@
 
 logger = logging.getLogger(__name__)
 
+if typing.TYPE_CHECKING:
+    from charm import MySQLOperatorCharm
+
 
 class MySQLResetRootPasswordAndStartMySQLDError(Error):
     """Exception raised when there's an error resetting root password and starting mysqld."""
@@ -103,7 +106,7 @@ def __init__(
         monitoring_password: str,
         backups_user: str,
         backups_password: str,
-        charm: CharmBase,
+        charm: "MySQLOperatorCharm",
     ):
         """Initialize the MySQL class.
 
@@ -233,6 +236,16 @@ def get_available_memory(self) -> int:
             logger.error("Failed to query system memory")
             raise MySQLGetAvailableMemoryError
 
+    @override
+    def set_cluster_primary(self, new_primary_address: str) -> None:
+        """Set the primary instance of the cluster.
+
+        Args:
+            new_primary_address: the address of the new primary instance
+        """
+        super().set_cluster_primary(new_primary_address)
+        self.charm.database_relation._update_endpoints_all_relations(None)
+
     def write_mysqld_config(self, profile: str, memory_limit: Optional[int]) -> None:
         """Create custom mysql config file.
 
@@ -356,11 +369,11 @@ def reset_root_password_and_start_mysqld(self) -> None:
                 except MySQLServiceNotRunningError:
                     raise MySQLResetRootPasswordAndStartMySQLDError("mysqld service not running")
 
-    @retry(reraise=True, stop=stop_after_delay(120), wait=wait_fixed(5))
+    @retry(reraise=True, stop=stop_after_delay(300), wait=wait_fixed(5))
     def wait_until_mysql_connection(self, check_port: bool = True) -> None:
         """Wait until a connection to MySQL has been obtained.
 
-        Retry every 5 seconds for 120 seconds if there is an issue obtaining a connection.
+        Retry every 5 seconds for 300 seconds if there is an issue obtaining a connection.
         """
         logger.debug("Waiting for MySQL connection")
 

src/relations/mysql_provider.py

@@ -20,7 +20,7 @@
 )
 from ops.charm import RelationBrokenEvent, RelationDepartedEvent, RelationJoinedEvent
 from ops.framework import Object
-from ops.model import BlockedStatus
+from ops.model import BlockedStatus, Relation
 
 from constants import DB_RELATION_NAME, PASSWORD_LENGTH, PEER
 from utils import generate_random_password
@@ -55,29 +55,30 @@ def __init__(self, charm: "MySQLOperatorCharm"):
         self.framework.observe(self.charm.on.leader_elected, self._update_endpoints_all_relations)
         self.framework.observe(self.charm.on.update_status, self._update_endpoints_all_relations)
 
+    @property
+    def active_relations(self) -> list[Relation]:
+        """Return the active relations."""
+        relation_data = self.database.fetch_relation_data()
+        return [
+            rel
+            for rel in self.model.relations[DB_RELATION_NAME]
+            if rel.id in relation_data  # rel.id in relation data after on_database_requested
+        ]
+
     def _update_endpoints_all_relations(self, _):
         """Update endpoints for all relations."""
         if not self.charm.unit.is_leader():
             return
-        # get all relations involving the database relation
-        relations = list(self.model.relations[DB_RELATION_NAME])
-        # check if there are relations in place
-        if len(relations) == 0:
-            return
 
         if not self.charm.cluster_initialized or not self.charm.unit_peer_data.get(
             "unit-initialized"
         ):
             logger.debug("Waiting cluster/unit to be initialized")
             return
 
-        relation_data = self.database.fetch_relation_data()
         # for all relations update the read-only-endpoints
-        for relation in relations:
+        for relation in self.active_relations:
             # check if the on_database_requested has been executed
-            if relation.id not in relation_data:
-                logger.debug("On database requested not happened yet! Nothing to do in this case")
-                continue
             self._update_endpoints(relation.id, relation.app.name)
 
     def _on_relation_departed(self, event: RelationDepartedEvent):
@@ -207,6 +208,7 @@ def _on_database_requested(self, event: DatabaseRequestedEvent):
         # get base relation data
         relation_id = event.relation.id
         db_name = event.database
+        assert db_name, "Database name must be provided"
         extra_user_roles = []
         if event.extra_user_roles:
             extra_user_roles = event.extra_user_roles.split(",")
@@ -272,8 +274,8 @@ def _on_database_broken(self, event: RelationBrokenEvent) -> None:
             # https://github.com/canonical/mysql-operator/issues/32
             return
 
+        relation_id = event.relation.id
         try:
-            relation_id = event.relation.id
             self.charm._mysql.delete_users_for_relation(relation_id)
             logger.info(f"Removed user for relation {relation_id}")
         except (MySQLDeleteUsersForRelationError, KeyError):

src/upgrade.py

@@ -17,6 +17,7 @@
     VersionError,
 )
 from charms.mysql.v0.mysql import (
+    MySQLGetClusterEndpointsError,
     MySQLGetMySQLVersionError,
     MySQLServerNotUpgradableError,
     MySQLSetClusterPrimaryError,
@@ -171,6 +172,11 @@ def _on_upgrade_charm_check_legacy(self, event) -> None:
     @override
     def _on_upgrade_granted(self, event: UpgradeGrantedEvent) -> None:  # noqa: C901
         """Handle the upgrade granted event."""
+        if self.charm.unit.is_leader():
+            # preemptively change primary on leader unit
+            # we assume the leader is primary, since the switchover is done on pre-upgrade-check
+            self._primary_switchover()
+
         try:
             self.charm.unit.status = MaintenanceStatus("stopping services..")
             self.charm._mysql.stop_mysqld()
@@ -260,6 +266,21 @@ def _recover_single_unit_cluster(self) -> None:
         logger.debug("Recovering single unit cluster")
         self.charm._mysql.reboot_from_complete_outage()
 
+    def _primary_switchover(self) -> None:
+        """Switchover primary to the first available RO endpoint."""
+        try:
+            _, ro_endpoints, _ = self.charm._mysql.get_cluster_endpoints(get_ips=False)
+            if not ro_endpoints:
+                # no ro endpoints, can't switchover
+                return
+            new_primary_address = ro_endpoints.split(",")[0]
+            self.charm._mysql.set_cluster_primary(new_primary_address)
+        except (MySQLSetClusterPrimaryError, MySQLGetClusterEndpointsError):
+            # If upgrading mysql version, older mysqlsh will fail to set primary
+            logger.warning(
+                "Failed to switchover primary. Endpoints will be updated after upgrade."
+            )
+
     def _on_upgrade_changed(self, _) -> None:
         """Handle the upgrade changed event.
 

tests/unit/test_database.py

@@ -4,6 +4,7 @@
 import unittest
 from unittest.mock import patch
 
+from charms.mysql.v0.mysql import RouterUser
 from ops.testing import Harness
 
 from charm import MySQLOperatorCharm
@@ -82,3 +83,23 @@ def test_database_requested(
         _create_application_database_and_scoped_user.assert_called_once()
         _get_cluster_endpoints.assert_called_once()
         _get_mysql_version.assert_called_once()
+
+    @patch("relations.mysql_provider.MySQLProvider._on_database_broken")
+    @patch("mysql_vm_helpers.MySQL.remove_router_from_cluster_metadata")
+    @patch("mysql_vm_helpers.MySQL.delete_user")
+    @patch("mysql_vm_helpers.MySQL.get_mysql_router_users_for_unit")
+    def test_relation_departed(
+        self,
+        _get_users,
+        _delete_user,
+        _remove_router,
+        _on_database_broken,
+    ):
+        self.harness.set_leader(True)
+
+        router_user = RouterUser(username="user1", router_id="router_id")
+        _get_users.return_value = [router_user]
+
+        self.harness.remove_relation(self.database_relation_id)
+        _delete_user.assert_called_once_with("user1")
+        _remove_router.assert_called_once_with("router_id")

tests/unit/test_upgrade.py

@@ -294,3 +294,11 @@ def test_prepare_upgrade_from_legacy(self):
             self.harness.get_relation_data(self.upgrade_relation_id, "mysql")["upgrade-stack"],
             "[0, 1]",
         )
+
+    @patch("charm.MySQLOperatorCharm._mysql")
+    def test_primary_switchover(self, _mysql):
+        _mysql.get_cluster_endpoints.return_value = (None, "1.1.1.1:3306,1.1.1.2:3306", None)
+
+        self.charm.upgrade._primary_switchover()
+
+        _mysql.set_cluster_primary.assert_called_once_with("1.1.1.1:3306")