[MISC] Port MySQL operator to Python 3.10+

src/charm.py

@@ -15,7 +15,6 @@
 import socket
 import subprocess
 from time import sleep
-from typing import Optional
 
 import ops
 from charms.data_platform_libs.v0.data_models import TypedCharmBase
@@ -400,7 +399,7 @@ def _on_database_storage_detaching(self, _) -> None:
         if not self._mysql.is_instance_in_cluster(self.unit_label):
             return
 
-        def _get_leader_unit() -> Optional[Unit]:
+        def _get_leader_unit() -> Unit | None:
             """Get the leader unit."""
             for unit in self.peers.units:
                 if self.peers.data[unit]["leader"] == "true":
@@ -630,7 +629,7 @@ def _on_cos_agent_relation_broken(self, _: RelationBrokenEvent) -> None:
     # =======================
 
     @property
-    def tracing_endpoint(self) -> Optional[str]:
+    def tracing_endpoint(self) -> str | None:
         """Otlp http endpoint for charm instrumentation."""
         return self.tracing_endpoint_config
 
@@ -665,15 +664,15 @@ def unit_fqdn(self) -> str:
         return socket.getfqdn()
 
     @property
-    def restart_peers(self) -> Optional[ops.Relation]:
+    def restart_peers(self) -> ops.Relation | None:
         """Retrieve the peer relation."""
         return self.model.get_relation("restart")
 
     def is_unit_busy(self) -> bool:
         """Returns whether the unit is in blocked state and should not run any operations."""
         return self.unit_peer_data.get("member-state") == "waiting"
 
-    def get_unit_hostname(self, unit_name: Optional[str] = None) -> str:
+    def get_unit_hostname(self, unit_name: str | None = None) -> str:
         """Get the hostname of the unit."""
         if unit_name:
             unit = self.model.get_unit(unit_name)
@@ -876,7 +875,7 @@ def _is_unit_waiting_to_join_cluster(self) -> bool:
             and self.cluster_initialized
         )
 
-    def _get_primary_from_online_peer(self) -> Optional[str]:
+    def _get_primary_from_online_peer(self) -> str | None:
         """Get the primary address from an online peer."""
         for unit in self.peers.units:
             if self.peers.data[unit].get("member-state") == "online":

src/config.py

@@ -8,7 +8,6 @@
 import logging
 import os
 import re
-from typing import Optional
 
 from charms.data_platform_libs.v0.data_models import BaseConfigModel
 from charms.mysql.v0.mysql import MAX_CONNECTIONS_FLOOR
@@ -44,7 +43,7 @@ def filter_static_keys(self, keys: set) -> set:
         return keys - self.static_config
 
     @property
-    def custom_config(self) -> Optional[dict]:
+    def custom_config(self) -> dict | None:
         """Return current custom config dict."""
         if not os.path.exists(self.config_file_path):
             return None
@@ -61,12 +60,12 @@ class CharmConfig(BaseConfigModel):
     """Manager for the structured configuration."""
 
     profile: str
-    cluster_name: Optional[str]
-    cluster_set_name: Optional[str]
-    profile_limit_memory: Optional[int]
-    mysql_interface_user: Optional[str]
-    mysql_interface_database: Optional[str]
-    experimental_max_connections: Optional[int]
+    cluster_name: str | None
+    cluster_set_name: str | None
+    profile_limit_memory: int | None
+    mysql_interface_user: str | None
+    mysql_interface_database: str | None
+    experimental_max_connections: int | None
     binlog_retention_days: int
     plugin_audit_enabled: bool
     plugin_audit_strategy: str
@@ -75,7 +74,7 @@ class CharmConfig(BaseConfigModel):
 
     @validator("profile")
     @classmethod
-    def profile_values(cls, value: str) -> Optional[str]:
+    def profile_values(cls, value: str) -> str | None:
         """Check profile config option is one of `testing` or `production`."""
         if value not in ["testing", "production"]:
             raise ValueError("Value not one of 'testing' or 'production'")
@@ -84,7 +83,7 @@ def profile_values(cls, value: str) -> Optional[str]:
 
     @validator("cluster_name", "cluster_set_name")
     @classmethod
-    def cluster_name_validator(cls, value: str) -> Optional[str]:
+    def cluster_name_validator(cls, value: str) -> str | None:
         """Check for valid cluster, cluster-set name.
 
         Limited to 63 characters, and must start with a letter and
@@ -106,7 +105,7 @@ def cluster_name_validator(cls, value: str) -> Optional[str]:
 
     @validator("profile_limit_memory")
     @classmethod
-    def profile_limit_memory_validator(cls, value: int) -> Optional[int]:
+    def profile_limit_memory_validator(cls, value: int) -> int | None:
         """Check profile limit memory."""
         if value < 600:
             raise ValueError("MySQL Charm requires at least 600MB for bootstrapping")
@@ -117,7 +116,7 @@ def profile_limit_memory_validator(cls, value: int) -> Optional[int]:
 
     @validator("experimental_max_connections")
     @classmethod
-    def experimental_max_connections_validator(cls, value: int) -> Optional[int]:
+    def experimental_max_connections_validator(cls, value: int) -> int | None:
         """Check experimental max connections."""
         if value < MAX_CONNECTIONS_FLOOR:
             raise ValueError(
@@ -138,7 +137,7 @@ def binlog_retention_days_validator(cls, value: int) -> int:
 
     @validator("plugin_audit_strategy")
     @classmethod
-    def plugin_audit_strategy_validator(cls, value: str) -> Optional[str]:
+    def plugin_audit_strategy_validator(cls, value: str) -> str | None:
         """Check profile config option is one of `testing` or `production`."""
         if value not in ["async", "semi-async"]:
             raise ValueError("Value not one of 'async' or 'semi-async'")
@@ -147,7 +146,7 @@ def plugin_audit_strategy_validator(cls, value: str) -> Optional[str]:
 
     @validator("logs_audit_policy")
     @classmethod
-    def logs_audit_policy_validator(cls, value: str) -> Optional[str]:
+    def logs_audit_policy_validator(cls, value: str) -> str | None:
         """Check values for audit log policy."""
         valid_values = ["all", "logins", "queries"]
         if value not in valid_values:

src/mysql_vm_helpers.py

@@ -12,7 +12,7 @@
 import subprocess
 import tempfile
 import typing
-from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
+from typing import Any, Iterable
 
 import jinja2
 import pexpect
@@ -436,8 +436,8 @@ def wait_until_mysql_connection(self, check_port: bool = True) -> None:
     def execute_backup_commands(  # type: ignore
         self,
         s3_directory: str,
-        s3_parameters: Dict[str, str],
-    ) -> Tuple[str, str]:
+        s3_parameters: dict[str, str],
+    ) -> tuple[str, str]:
         """Executes commands to create a backup."""
         return super().execute_backup_commands(
             s3_directory,
@@ -465,13 +465,13 @@ def delete_temp_backup_directory(  # type: ignore
     def retrieve_backup_with_xbcloud(  # type: ignore
         self,
         backup_id: str,
-        s3_parameters: Dict[str, str],
+        s3_parameters: dict[str, str],
         temp_restore_directory: str = CHARMED_MYSQL_COMMON_DIRECTORY,
         xbcloud_location: str = CHARMED_MYSQL_XBCLOUD_LOCATION,
         xbstream_location: str = CHARMED_MYSQL_XBSTREAM_LOCATION,
         user=ROOT_SYSTEM_USER,
         group=ROOT_SYSTEM_USER,
-    ) -> Tuple[str, str, str]:
+    ) -> tuple[str, str, str]:
         """Retrieve the provided backup with xbcloud."""
         return super().retrieve_backup_with_xbcloud(
             backup_id,
@@ -483,7 +483,7 @@ def retrieve_backup_with_xbcloud(  # type: ignore
             group,
         )
 
-    def prepare_backup_for_restore(self, backup_location: str) -> Tuple[str, str]:
+    def prepare_backup_for_restore(self, backup_location: str) -> tuple[str, str]:
         """Prepare the download backup for restore with xtrabackup --prepare."""
         return super().prepare_backup_for_restore(
             backup_location,
@@ -504,7 +504,7 @@ def empty_data_files(self) -> None:
     def restore_backup(
         self,
         backup_location: str,
-    ) -> Tuple[str, str]:
+    ) -> tuple[str, str]:
         """Restore the provided prepared backup."""
         # TODO: remove workaround for changing permissions and ownership of data
         # files once restore backup commands can be run with snap_daemon user
@@ -572,13 +572,13 @@ def delete_temp_restore_directory(self) -> None:
 
     def _execute_commands(
         self,
-        commands: List[str],
+        commands: list[str],
         bash: bool = False,
         user: str = None,
         group: str = None,
-        env_extra: Dict = {},
-        stream_output: Optional[str] = None,
-    ) -> Tuple[str, str]:
+        env_extra: dict = {},
+        stream_output: str | None = None,
+    ) -> tuple[str, str]:
         """Execute commands on the server where mysql is running.
 
         Args:
@@ -802,10 +802,10 @@ def _run_mysqlsh_script(
 
     def _run_mysqlcli_script(
         self,
-        script: Union[Tuple[Any, ...], List[Any]],
+        script: tuple[Any, ...] | list[Any],
         user: str = "root",
-        password: Optional[str] = None,
-        timeout: Optional[int] = None,
+        password: str | None = None,
+        timeout: int | None = None,
         exception_as_warning: bool = False,
         log_errors: bool = True,
     ) -> list:
@@ -1001,7 +1001,7 @@ def write_content_to_file(
         os.chmod(path, mode=permission)
 
     @staticmethod
-    def fetch_error_log() -> Optional[str]:
+    def fetch_error_log() -> str | None:
         """Fetch the mysqld error log."""
         if os.path.exists(f"{CHARMED_MYSQL_COMMON_DIRECTORY}/var/log/mysql/error.log"):
             # can be empty if just rotated

src/relations/db_router.py

@@ -7,7 +7,6 @@
 import logging
 import typing
 from collections import namedtuple
-from typing import Dict, List, Set, Tuple
 
 from charms.mysql.v0.mysql import (
     MySQLCheckUserExistenceError,
@@ -70,7 +69,7 @@ def _get_or_set_password_in_peer_databag(self, username: str) -> str:
 
     def _get_requested_users_from_relation_databag(
         self, db_router_databag: RelationDataContent
-    ) -> List[RequestedUser]:
+    ) -> list[RequestedUser]:
         """Retrieve requested user information from the db-router relation databag.
 
         Args:
@@ -109,8 +108,8 @@ def _get_requested_users_from_relation_databag(
         return requested_users
 
     def _create_requested_users(
-        self, requested_users: List[RequestedUser], user_unit_name: str
-    ) -> Tuple[Dict[str, str], Set[str]]:
+        self, requested_users: list[RequestedUser], user_unit_name: str
+    ) -> tuple[dict[str, str], set[str]]:
         """Create the requested users and said user scoped databases.
 
         Args: