diff --git a/.flake8 b/.flake8
new file mode 100644
index 0000000..6deafc2
--- /dev/null
+++ b/.flake8
@@ -0,0 +1,2 @@
+[flake8]
+max-line-length = 120
diff --git a/.github/workflows/linters.yaml b/.github/workflows/linters.yaml
deleted file mode 100644
index 6745ffe..0000000
--- a/.github/workflows/linters.yaml
+++ /dev/null
@@ -1,16 +0,0 @@
-name: linters
-on: push
-
-jobs:
-  super-lint:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - uses: github/super-linter@v4
-        env:
-          DEFAULT_BRANCH: main
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          VALIDATE_ALL_CODEBASE: true
-          VALIDATE_DOCKERFILE_HADOLINT: false
-          VALIDATE_PYTHON_MYPY: false
-          VALIDATE_JSCPD: false
diff --git a/.gitignore b/.gitignore
index 32e35b0..1ae05e4 100755
--- a/.gitignore
+++ b/.gitignore
@@ -68,4 +68,4 @@
 *.log
 
 # envvar openrc file
-*openrc.sh
\ No newline at end of file
+*openrc.sh
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 0000000..4975271
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,30 @@
+repos:
+  - repo: https://github.com/compilerla/conventional-pre-commit
+    rev: v2.0.0
+    hooks:
+      - id: conventional-pre-commit
+        stages:
+          - commit-msg
+
+  - repo: https://github.com/psf/black
+    rev: 24.8.0
+    hooks:
+      - id: black
+
+  - repo: https://github.com/pycqa/flake8
+    rev: 5.0.4
+    hooks:
+      - id: flake8
+
+  - repo: https://github.com/pycqa/isort
+    rev: 5.13.2
+    hooks:
+      - id: isort
+
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.3.0
+    hooks:
+      - id: check-yaml
+        args: [--allow-multiple-documents]
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
diff --git a/doc/source/conf.py b/doc/source/conf.py
index 1c590d6..9055a03 100755
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -11,6 +11,7 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from __future__ import annotations
 
 import os
 import sys
@@ -39,7 +40,7 @@
 # openstackdocstheme options
 openstackdocs_repo_name = "openstack/staffeln"
 openstackdocs_bug_project = (
-    "replace with the name of the project on Launchpad or the ID from Storyboard"
+    "replace with the name of the project on " "Launchpad or the ID from Storyboard"
 )
 openstackdocs_bug_tag = ""
 
diff --git a/hack/stack.sh b/hack/stack.sh
index 497b29a..4876c88 100755
--- a/hack/stack.sh
+++ b/hack/stack.sh
@@ -36,7 +36,7 @@
 SWIFT_REPLICAS=1
 enable_plugin neutron https://opendev.org/openstack/neutron
 #swift
-enable_service s-proxy s-object s-container s-account 
+enable_service s-proxy s-object s-container s-account
 # Cinder
 enable_service c-bak
 [[post-config|/etc/neutron/neutron.conf]]
diff --git a/releasenotes/source/conf.py b/releasenotes/source/conf.py
index 65d2460..d4b373e 100755
--- a/releasenotes/source/conf.py
+++ b/releasenotes/source/conf.py
@@ -11,7 +11,6 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 # This file is execfile()d with the current directory set to its
 # containing dir.
 #
@@ -20,20 +19,18 @@
 #
 # All configuration values have a default; values that are commented out
 # serve to show the default.
-
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 # sys.path.insert(0, os.path.abspath('.'))
-
 # -- General configuration ------------------------------------------------
-
 # If your documentation needs a minimal Sphinx version, state it here.
 # needs_sphinx = '1.0'
-
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
+from __future__ import annotations
+
 extensions = [
     "openstackdocstheme",
     "reno.sphinxext",
diff --git a/requirements.txt b/requirements.txt
index 3789929..140798f 100755
--- a/requirements.txt
+++ b/requirements.txt
@@ -20,5 +20,3 @@
 tooz # Apache-2.0
 sherlock>=0.4.1 # MIT
 kubernetes # Apache-2.0
-# email
-# smtplib
diff --git a/setup.cfg b/setup.cfg
index 5466daa..53df199 100755
--- a/setup.cfg
+++ b/setup.cfg
@@ -17,6 +17,8 @@
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: Implementation :: CPython
 
@@ -35,4 +37,4 @@
 wsgi_scripts =
     staffeln-api-wsgi = staffeln.api:app
 staffeln.database.migration_backend =
-    sqlalchemy = staffeln.db.sqlalchemy.migration
\ No newline at end of file
+    sqlalchemy = staffeln.db.sqlalchemy.migration
diff --git a/setup.py b/setup.py
index 0346ed3..673123b 100755
--- a/setup.py
+++ b/setup.py
@@ -12,8 +12,9 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 # THIS FILE IS MANAGED BY THE GLOBAL REQUIREMENTS REPO - DO NOT EDIT
+from __future__ import annotations
+
 import setuptools
 
 setuptools.setup(setup_requires=["pbr"], pbr=True)
diff --git a/staffeln/__init__.py b/staffeln/__init__.py
index 5612b0d..78fc3f2 100755
--- a/staffeln/__init__.py
+++ b/staffeln/__init__.py
@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
 # a copy of the License at
@@ -11,6 +10,7 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
+from __future__ import annotations
 
 import pbr.version
 
diff --git a/staffeln/api/app.py b/staffeln/api/app.py
index bf1234e..8b54dad 100755
--- a/staffeln/api/app.py
+++ b/staffeln/api/app.py
@@ -1,5 +1,8 @@
+from __future__ import annotations
+
 from flask import Flask, Response, request
 from oslo_log import log
+
 from staffeln import objects
 from staffeln.common import context
 
@@ -22,8 +25,8 @@
     backup = objects.Volume.get_backup_by_backup_id(  # pylint: disable=E1120
         context=ctx, backup_id=request.args["backup_id"]
     )
-    # backup_info is None when there is no entry of the backup id in backup_table.
-    # So the backup should not be the automated backup.
+    # backup_info is None when there is no entry of the backup id in
+    # backup_table. So the backup should not be the automated backup.
     if backup is None:
         return Response(
             "True",
diff --git a/staffeln/api/middleware/parsable_error.py b/staffeln/api/middleware/parsable_error.py
index 2b49f83..343c8c2 100755
--- a/staffeln/api/middleware/parsable_error.py
+++ b/staffeln/api/middleware/parsable_error.py
@@ -17,8 +17,10 @@
 
 Based on pecan.middleware.errordocument
 """
+from __future__ import annotations
 
 from oslo_serialization import jsonutils
+
 from staffeln.i18n import _
 
 
diff --git a/staffeln/api/wsgi.py b/staffeln/api/wsgi.py
index bef4092..6965beb 100755
--- a/staffeln/api/wsgi.py
+++ b/staffeln/api/wsgi.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import app
 
 if __name__ == "__main__":
diff --git a/staffeln/cmd/api.py b/staffeln/cmd/api.py
index a46656c..a175089 100755
--- a/staffeln/cmd/api.py
+++ b/staffeln/cmd/api.py
@@ -1,9 +1,13 @@
 """Starter script for Staffeln API service"""
+
+from __future__ import annotations
+
 import os
 import sys
 
-import staffeln.conf
 from oslo_log import log as logging
+
+import staffeln.conf
 from staffeln.api import app as api_app
 from staffeln.common import service
 from staffeln.i18n import _
diff --git a/staffeln/cmd/conductor.py b/staffeln/cmd/conductor.py
index f4c9579..eaec3cf 100755
--- a/staffeln/cmd/conductor.py
+++ b/staffeln/cmd/conductor.py
@@ -1,8 +1,11 @@
 """Starter script for the staffeln conductor service."""
 
+from __future__ import annotations
+
 import cotyledon
-import staffeln.conf
 from cotyledon import oslo_config_glue
+
+import staffeln.conf
 from staffeln.common import service
 from staffeln.conductor import manager
 
@@ -13,9 +16,15 @@
     service.prepare_service()
 
     sm = cotyledon.ServiceManager()
-    sm.add(manager.BackupManager, workers=CONF.conductor.backup_workers, args=(CONF,))
     sm.add(
-        manager.RotationManager, workers=CONF.conductor.rotation_workers, args=(CONF,)
+        manager.BackupManager,
+        workers=CONF.conductor.backup_workers,
+        args=(CONF,),
+    )
+    sm.add(
+        manager.RotationManager,
+        workers=CONF.conductor.rotation_workers,
+        args=(CONF,),
     )
     oslo_config_glue.setup(sm, CONF)
     sm.run()
diff --git a/staffeln/cmd/dbmanage.py b/staffeln/cmd/dbmanage.py
index d4706cf..bd6f01d 100644
--- a/staffeln/cmd/dbmanage.py
+++ b/staffeln/cmd/dbmanage.py
@@ -2,9 +2,12 @@
 Run storage database migration.
 """
 
+from __future__ import annotations
+
 import sys
 
 from oslo_config import cfg
+
 from staffeln import conf
 from staffeln.common import service
 from staffeln.db import migration
@@ -33,7 +36,10 @@
 
 
 command_opt = cfg.SubCommandOpt(
-    "command", title="Command", help="Available commands", handler=add_command_parsers
+    "command",
+    title="Command",
+    help="Available commands",
+    handler=add_command_parsers,
 )
 
 
diff --git a/staffeln/common/auth.py b/staffeln/common/auth.py
index e23ef71..b64c515 100755
--- a/staffeln/common/auth.py
+++ b/staffeln/common/auth.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import openstack
 
 
diff --git a/staffeln/common/config.py b/staffeln/common/config.py
index f71a378..5b69fb4 100755
--- a/staffeln/common/config.py
+++ b/staffeln/common/config.py
@@ -1,4 +1,6 @@
 # from staffeln.common import rpc
+from __future__ import annotations
+
 import staffeln.conf
 from staffeln import version
 
diff --git a/staffeln/common/constants.py b/staffeln/common/constants.py
index b7d6d09..d065966 100644
--- a/staffeln/common/constants.py
+++ b/staffeln/common/constants.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 BACKUP_INIT = 4
 BACKUP_FAILED = 3
 BACKUP_COMPLETED = 2
diff --git a/staffeln/common/context.py b/staffeln/common/context.py
index c6046e1..d789a58 100644
--- a/staffeln/common/context.py
+++ b/staffeln/common/context.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from oslo_context import context
 from oslo_log import log
 
@@ -5,7 +7,11 @@
 
 
 class RequestContext(context.RequestContext):
-    """Added security context with request parameters from openstack common library"""
+    """Added security context
+
+    Added security context with request
+    parameters from openstack common library
+    """
 
     def __init__(
         self,
@@ -14,7 +20,7 @@
         instance_id=None,
         executed_at=None,
         backup_status=None,
-        **kwargs
+        **kwargs,
     ):
         self.backup_id = backup_id
         self.volume_id = volume_id
diff --git a/staffeln/common/email.py b/staffeln/common/email.py
index cf6e937..368028b 100644
--- a/staffeln/common/email.py
+++ b/staffeln/common/email.py
@@ -1,5 +1,7 @@
 """ Email module with SMTP"""
 
+from __future__ import annotations
+
 import smtplib
 from email import utils
 from email.header import Header
@@ -32,10 +34,12 @@
 
     try:
         smtp_obj = smtplib.SMTP(
-            smtp_profile["smtp_server_domain"], smtp_profile["smtp_server_port"]
+            smtp_profile["smtp_server_domain"],
+            smtp_profile["smtp_server_port"],
         )
         smtp_obj.connect(
-            smtp_profile["smtp_server_domain"], smtp_profile["smtp_server_port"]
+            smtp_profile["smtp_server_domain"],
+            smtp_profile["smtp_server_port"],
         )
         smtp_obj.ehlo()
         smtp_obj.starttls()
@@ -43,7 +47,9 @@
         # SMTP Login
         smtp_obj.login(smtp_profile["src_email"], smtp_profile["src_pwd"])
         smtp_obj.sendmail(
-            smtp_profile["src_email"], smtp_profile["dest_email"], msg.as_string()
+            smtp_profile["src_email"],
+            smtp_profile["dest_email"],
+            msg.as_string(),
         )
         # Email Sent
     except smtplib.SMTPException as error:
diff --git a/staffeln/common/lock.py b/staffeln/common/lock.py
index 4c05626..9f7db41 100644
--- a/staffeln/common/lock.py
+++ b/staffeln/common/lock.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import errno
 import glob
 import os
@@ -8,9 +10,10 @@
 
 import sherlock
 from oslo_log import log
-from staffeln import conf, exception
 from tooz import coordination
 
+from staffeln import conf, exception
+
 CONF = conf.CONF
 LOG = log.getLogger(__name__)
 
@@ -146,7 +149,10 @@
     """
 
     def __init__(
-        self, expire: int = 3600, timeout: int = 10, namespace: str = "openstack"
+        self,
+        expire: int = 3600,
+        timeout: int = 10,
+        namespace: str = "openstack",
     ):
         self.timeout = timeout
         self.expire = expire
diff --git a/staffeln/common/openstack.py b/staffeln/common/openstack.py
index 9f412e8..710d112 100644
--- a/staffeln/common/openstack.py
+++ b/staffeln/common/openstack.py
@@ -1,5 +1,8 @@
+from __future__ import annotations
+
 from openstack import exceptions, proxy
 from oslo_log import log
+
 from staffeln.common import auth
 from staffeln.i18n import _
 
@@ -66,7 +69,9 @@
     def get_servers(self, project_id=None, all_projects=True, details=True):
         if project_id is not None:
             return self.conn.compute.servers(
-                details=details, all_projects=all_projects, project_id=project_id
+                details=details,
+                all_projects=all_projects,
+                project_id=project_id,
             )
         else:
             return self.conn.compute.servers(details=details, all_projects=all_projects)
@@ -75,10 +80,6 @@
         return self.conn.get_volume_by_id(uuid)
 
     def get_backup(self, uuid, project_id=None):
-        # return conn.block_storage.get_backup(
-        #     project_id=project_id, backup_id=uuid,
-        # )
-        # conn.block_storage.backups(volume_id=uuid,project_id=project_id)
         try:
             return self.conn.get_volume_backup(uuid)
         except exceptions.ResourceNotFound:
@@ -93,9 +94,6 @@
         name=None,
         incremental=False,
     ):
-        # return conn.block_storage.create_backup(
-        #     volume_id=queue.volume_id, force=True, project_id=queue.project_id, name="name"
-        # )
         return self.conn.create_volume_backup(
             volume_id=volume_id,
             force=force,
@@ -112,7 +110,8 @@
         LOG.debug(f"Start deleting backup {uuid} in OpenStack.")
         try:
             self.conn.delete_volume_backup(uuid, force=force)
-            # TODO(Alex): After delete the backup generator, need to set the volume status again
+            # TODO(Alex): After delete the backup generator,
+            # need to set the volume status again
         except exceptions.ResourceNotFound:
             return None
 
@@ -128,7 +127,8 @@
 
     # rewrite openstasdk._block_storage.get_volume_quotas
     # added usage flag
-    # ref: https://docs.openstack.org/api-ref/block-storage/v3/?expanded=#show-quota-usage-for-a-project
+    # ref: https://docs.openstack.org/api-ref/block-storage/v3/?
+    # expanded=#show-quota-usage-for-a-project
     def _get_volume_quotas(self, project_id, usage=True):
         """Get volume quotas for a project
 
diff --git a/staffeln/common/service.py b/staffeln/common/service.py
index d2ad7a5..98399f6 100755
--- a/staffeln/common/service.py
+++ b/staffeln/common/service.py
@@ -11,9 +11,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from __future__ import annotations
+
+from oslo_log import log as logging
 
 import staffeln.conf
-from oslo_log import log as logging
 from staffeln import objects
 from staffeln.common import config
 
diff --git a/staffeln/common/short_id.py b/staffeln/common/short_id.py
index 18be04c..e182ad1 100755
--- a/staffeln/common/short_id.py
+++ b/staffeln/common/short_id.py
@@ -2,10 +2,13 @@
 The IDs each comprise 12 (lower-case) alphanumeric characters.
 """
 
+from __future__ import annotations
+
 import base64
 import uuid
 
 import six
+
 from staffeln.i18n import _
 
 
diff --git a/staffeln/common/time.py b/staffeln/common/time.py
index 103096a..08fd5d1 100644
--- a/staffeln/common/time.py
+++ b/staffeln/common/time.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import re
 
 from dateutil.relativedelta import relativedelta
@@ -6,8 +8,10 @@
 DEFAULT_TIME_FORMAT = "%Y-%m-%d %H:%M:%S"
 
 regex = re.compile(
-    r"((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?"
-    r"((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?"
+    r"((?P<years>\d+?)y)?((?P<months>\d+?)mon)?"
+    r"((?P<weeks>\d+?)w)?((?P<days>\d+?)d)?"
+    r"((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?"
+    r"((?P<seconds>\d+?)s)?"
 )
 
 
@@ -31,7 +35,7 @@
         if empty_flag:
             return None
         return time_params
-    except:  # noqa: E722
+    except Exception:  # noqa: E722
         return None
 
 
@@ -45,7 +49,14 @@
 
 
 def timeago(
-    years=0, months=0, weeks=0, days=0, hours=0, minutes=0, seconds=0, from_date=None
+    years=0,
+    months=0,
+    weeks=0,
+    days=0,
+    hours=0,
+    minutes=0,
+    seconds=0,
+    from_date=None,
 ):
     if from_date is None:
         from_date = timeutils.utcnow()
diff --git a/staffeln/conductor/backup.py b/staffeln/conductor/backup.py
index 05f5cfd..760132c 100755
--- a/staffeln/conductor/backup.py
+++ b/staffeln/conductor/backup.py
@@ -1,12 +1,15 @@
+from __future__ import annotations
+
 import collections
 from datetime import timedelta, timezone
 
-import staffeln.conf
 from openstack.exceptions import HttpException as OpenstackHttpException
 from openstack.exceptions import ResourceNotFound as OpenstackResourceNotFound
 from openstack.exceptions import SDKException as OpenstackSDKException
 from oslo_log import log
 from oslo_utils import timeutils
+
+import staffeln.conf
 from staffeln import objects
 from staffeln.common import constants, context, openstack
 from staffeln.common import time as xtime
@@ -115,8 +118,7 @@
         return queue
 
     def create_queue(self, old_tasks):
-        """
-        Create the queue of all the volumes for backup
+        """Create the queue of all the volumes for backup
 
         :param old_tasks: Task list not completed in the previous cycle
         :type: List<Class objects.Queue>
@@ -129,7 +131,8 @@
         for old_task in old_tasks:
             old_task_volume_list.append(old_task.volume_id)
 
-        # 2. add new tasks in the queue which are not existing in the old task list
+        # 2. add new tasks in the queue which are not existing in the old task
+        # list
         task_list = self.check_instance_volumes()
         for task in task_list:
             if task.volume_id not in old_task_volume_list:
@@ -157,8 +160,8 @@
             res = volume["status"] in ("available", "in-use")
             if not res:
                 reason = _(
-                    "Volume %s is not triger new backup task because it is in %s status"
-                    % (volume_id, volume["status"])
+                    "Volume %s is not triger new backup task because "
+                    "it is in %s status" % (volume_id, volume["status"])
                 )
                 LOG.info(reason)
                 return reason
@@ -169,7 +172,7 @@
 
     def purge_backups(self, project_id=None):
         LOG.info(f"Start pruge backup tasks for project {project_id}")
-        # TODO make all this in a single DB command
+        # We can consider make all these in a single DB command
         success_tasks = self.get_queues(
             filters={
                 "backup_status": constants.BACKUP_COMPLETED,
@@ -252,10 +255,8 @@
             backup = self.openstacksdk.get_backup(backup_object.backup_id)
             if backup is None:
                 LOG.info(
-                    _(
-                        f"Backup {backup_object.backup_id} is removed from "
-                        "Openstack or cinder-backup is not existing in the cloud."
-                    )
+                    f"Backup {backup_object.backup_id} is removed from "
+                    "Openstack or cinder-backup is not existing in the cloud."
                 )
                 return backup_object.delete_backup()
             if backup["status"] in ("available"):
@@ -269,15 +270,13 @@
                 # backup_object.delete_backup()
             else:  # "deleting", "restoring"
                 LOG.info(
-                    _(
-                        "Rotation for the backup %s is skipped in this cycle "
-                        "because it is in %s status"
-                    )
-                    % (backup_object.backup_id, backup["status"])
+                    f"Rotation for the backup {backup_object.backup_id} "
+                    "is skipped in this cycle "
+                    f"because it is in {backup['status']} status"
                 )
 
         except OpenstackSDKException as e:
-            LOG.warn(_(f"Backup {backup_object.backup_id} deletion failed. {str(e)}"))
+            LOG.warn(f"Backup {backup_object.backup_id} deletion failed. {str(e)}")
             # We don't delete backup object if any exception occured
             # backup_object.delete_backup()
             return False
@@ -288,15 +287,14 @@
             project_id = backup_object.project_id
             if project_id not in self.project_list:
                 LOG.warn(
-                    _(
-                        f"Project {project_id} for backup "
-                        f"{backup_object.backup_id} is not existing in "
-                        "Openstack. Please check your access right to this project. "
-                        "Skip this backup from remove now and will retry later."
-                    )
+                    f"Project {project_id} for backup "
+                    f"{backup_object.backup_id} is not existing in "
+                    "Openstack. Please check your access right to this "
+                    "project. "
+                    "Skip this backup from remove now and will retry later."
                 )
-                # Don't remove backup object, keep it and retry on next periodic task
-                # backup_object.delete_backup()
+                # Don't remove backup object, keep it and retry on next
+                # periodic task backup_object.delete_backup()
                 return
 
             self.openstacksdk.set_project(self.project_list[project_id])
@@ -305,12 +303,9 @@
             )
             if backup is None:
                 LOG.info(
-                    _(
-                        "Backup %s is removed from Openstack "
-                        "or cinder-backup is not existing in the cloud. "
-                        "Start removing backup object from Staffeln."
-                        % backup_object.backup_id
-                    )
+                    f"Backup {backup_object.backup_id} is removed from "
+                    "Openstack or cinder-backup is not existing in the "
+                    "cloud. Start removing backup object from Staffeln."
                 )
                 return backup_object.delete_backup()
 
@@ -318,19 +313,17 @@
             # Don't remove backup until it's officially removed from Cinder
             # backup_object.delete_backup()
         except Exception as e:
-            if skip_inc_err and "Incremental backups exist for this backup" in str(e):
+            if skip_inc_err and ("Incremental backups exist for this backup" in str(e)):
                 LOG.debug(str(e))
             else:
                 LOG.info(
-                    _(
-                        f"Backup {backup_object.backup_id} deletion failed. "
-                        "Skip this backup from remove now and will retry later."
-                    )
+                    f"Backup {backup_object.backup_id} deletion failed. "
+                    "Skip this backup from remove now and will retry later."
                 )
                 LOG.debug(f"deletion failed {str(e)}")
 
-                # Don't remove backup object, keep it and retry on next periodic task
-                # backup_object.delete_backup()
+                # Don't remove backup object, keep it and retry on next
+                # periodic task backup_object.delete_backup()
 
     def update_project_list(self):
         projects = self.openstacksdk.get_projects()
@@ -338,8 +331,7 @@
             self.project_list[project.id] = project
 
     def _is_backup_required(self, volume_id):
-        """
-        Decide if the backup required based on the backup history
+        """Decide if the backup required based on the backup history
 
         If there is any backup created during certain time,
         will not trigger new backup request.
@@ -376,8 +368,7 @@
         return True
 
     def _is_incremental(self, volume_id):
-        """
-        Decide the backup method based on the backup history
+        """Decide the backup method based on the backup history
 
         It queries to select the last N backups from backup table and
         decide backup type as full if there is no full backup.
@@ -406,16 +397,12 @@
                     return True
         except Exception as e:
             LOG.debug(
-                _(
-                    "Failed to get backup history to decide backup method. Reason: %s"
-                    % str(e)
-                )
+                "Failed to get backup history to decide backup " f"method. Reason: {e}"
             )
         return False
 
     def check_instance_volumes(self):
-        """
-        Retrieves volume list to backup
+        """Retrieves volume list to backup
 
         Get the list of all the volumes from the project using openstacksdk.
         Function first list all the servers in the project and get the volumes
@@ -433,10 +420,8 @@
                 servers = self.openstacksdk.get_servers(project_id=project.id)
             except OpenstackHttpException as ex:
                 LOG.warn(
-                    _(
-                        "Failed to list servers in project %s. %s"
-                        % (project.id, str(ex))
-                    )
+                    f"Failed to list servers in project {project.id}. "
+                    f"{str(ex)} (status code: {ex.status_code})."
                 )
                 continue
             for server in servers:
@@ -501,8 +486,12 @@
 
         try:
             servers = self.openstacksdk.get_servers(all_projects=True)
-        except OpenstackHttpException:
-            LOG.warn(_("Failed to list servers for all projects."))
+        except OpenstackHttpException as ex:
+            servers = []
+            LOG.warn(
+                f"Failed to list servers for all projects. "
+                f"{str(ex)} (status code: {ex.status_code})."
+            )
 
         for server in servers:
             if CONF.conductor.retention_metadata_key in server.metadata:
@@ -511,21 +500,22 @@
                 ].lower()
                 if xtime.regex.fullmatch(server_retention_time):
                     LOG.debug(
-                        f"Found retention time ({server_retention_time}) defined for "
-                        f"server {server.id}, Adding it retention reference map."
+                        f"Found retention time ({server_retention_time}) "
+                        f"defined for server {server.id}, "
+                        "Adding it retention reference map."
                     )
                     retention_map[server.id] = server_retention_time
                 else:
                     LOG.info(
-                        f"Server retention time for instance {server.id} is incorrect. "
-                        "Please follow '<YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>"
+                        f"Server retention time for instance {server.id} is "
+                        "incorrect. Please follow "
+                        "'<YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>"
                         "h<MINUTES>min<SECONDS>s' format."
                     )
         return retention_map
 
     def _volume_queue(self, task):
-        """
-        Commits one backup task to queue table
+        """Commits one backup task to queue table
 
         :param task: One backup task
         :type: QueueMapping
@@ -539,7 +529,8 @@
         volume_queue.instance_name = task.instance_name
         volume_queue.volume_name = task.volume_name
         # NOTE(Oleks): Backup mode is inherited from backup service.
-        # Need to keep and navigate backup mode history, to decide a different mode per volume
+        # Need to keep and navigate backup mode history, to decide a different
+        # mode per volume
         volume_queue.incremental = task.incremental
 
         backup_method = "Incremental" if task.incremental else "Full"
@@ -553,6 +544,7 @@
 
     def create_volume_backup(self, task):
         """Initiate the backup of the volume
+
         :param task: Provide the map of the volume that needs
                   backup.
         This function will call the backupup api and change the
@@ -582,8 +574,13 @@
                 backup_method = "Incremental" if task.incremental else "Full"
                 LOG.info(
                     _(
-                        ("%s Backup (name: %s) for volume %s creating in project %s")
-                        % (backup_method, backup_name, task.volume_id, project_id)
+                        ("%s Backup (name: %s) for volume %s creating " "in project %s")
+                        % (
+                            backup_method,
+                            backup_name,
+                            task.volume_id,
+                            project_id,
+                        )
                     )
                 )
                 volume_backup = self.openstacksdk.create_backup(
@@ -599,24 +596,25 @@
                 inc_err_msg = "No backups available to do an incremental backup"
                 if inc_err_msg in str(error):
                     LOG.info(
-                        "Retry to create full backup for volume %s instead of incremental."
-                        % task.volume_id
+                        "Retry to create full backup for volume %s instead of "
+                        "incremental." % task.volume_id
                     )
                     task.incremental = False
                     task.save()
                 else:
                     reason = _(
-                        "Backup (name: %s) creation for the volume %s failled. %s"
-                        % (backup_name, task.volume_id, str(error)[:64])
+                        "Backup (name: %s) creation for the volume %s "
+                        "failled. %s" % (backup_name, task.volume_id, str(error)[:64])
                     )
                     LOG.warn(
-                        "Backup (name: %s) creation for the volume %s failled. %s"
-                        % (backup_name, task.volume_id, str(error))
+                        "Backup (name: %s) creation for the volume %s "
+                        "failled. %s" % (backup_name, task.volume_id, str(error))
                     )
                     task.reason = reason
                     task.backup_status = constants.BACKUP_FAILED
                     task.save()
-            # Added extra exception as OpenstackSDKException does not handle the keystone unauthourized issue.
+            # Added extra exception as OpenstackSDKException does not handle
+            # the keystone unauthourized issue.
             except Exception as error:
                 reason = _(
                     "Backup (name: %s) creation for the volume %s failled. %s"
@@ -647,7 +645,7 @@
 
     def process_failed_backup(self, task):
         # 1. notify via email
-        reason = _("The status of backup for the volume %s is error." % task.volume_id)
+        reason = f"The status of backup for the volume {task.volume_id} is error."
         LOG.warn(reason)
         # 2. delete backup generator
         try:
@@ -656,8 +654,8 @@
         except OpenstackHttpException as ex:
             LOG.warn(
                 _(
-                    "Failed to delete volume backup %s. %s. Need to delete manually."
-                    % (task.backup_id, str(ex))
+                    "Failed to delete volume backup %s. %s. Need "
+                    "to delete manually." % (task.backup_id, str(ex))
                 )
             )
         task.reason = reason
@@ -690,6 +688,7 @@
 
     def check_volume_backup_status(self, queue):
         """Checks the backup status of the volume
+
         :params: queue: Provide the map of the volume that needs backup
                  status checked.
         Call the backups api to see if the backup is successful.
@@ -724,7 +723,8 @@
 
     def _volume_backup(self, task):
         # matching_backups = [
-        #     g for g in self.available_backups if g.backup_id == task.backup_id
+        #     g for g in self.available_backups
+        #          if g.backup_id == task.backup_id
         # ]
         # if not matching_backups:
         volume_backup = objects.Volume(self.ctx)
diff --git a/staffeln/conductor/manager.py b/staffeln/conductor/manager.py
index 380c2f7..c43e13b 100755
--- a/staffeln/conductor/manager.py
+++ b/staffeln/conductor/manager.py
@@ -1,12 +1,15 @@
+from __future__ import annotations
+
 import threading
 import time
 from datetime import timedelta, timezone
 
 import cotyledon
-import staffeln.conf
 from futurist import periodics
 from oslo_log import log
 from oslo_utils import timeutils
+
+import staffeln.conf
 from staffeln import objects
 from staffeln.common import constants, context, lock
 from staffeln.common import time as xtime
@@ -58,7 +61,8 @@
                 LOG.info(_("cycle timein"))
                 for queue in queues_started:
                     LOG.debug(
-                        f"try to get lock and run task for volume: {queue.volume_id}."
+                        "try to get lock and run task for volume: "
+                        f"{queue.volume_id}."
                     )
                     with lock.Lock(
                         self.lock_mgt, queue.volume_id, remove_lock=True
@@ -82,7 +86,8 @@
             LOG.info(
                 _(
                     "Recycle timeout format is invalid. "
-                    "Follow <YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."
+                    "Follow <YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>h<MINUTES>"
+                    "min<SECONDS>s."
                 )
             )
             time_delta_dict = xtime.parse_timedelta_string(
@@ -230,14 +235,18 @@
             if backup_age > retention_time:
                 # Backup remain longer than retention, need to purge it.
                 LOG.debug(
-                    f"Found potential volume backup for retention: Backup ID: {backup.backup_id} "
-                    f"with backup age: {backup_age} (Target retention time: {retention_time})."
+                    "Found potential volume backup for retention: Backup "
+                    f"ID: {backup.backup_id} "
+                    f"with backup age: {backup_age} (Target retention "
+                    f"time: {retention_time})."
                 )
                 return True
         elif now - self.threshold_strtime < backup_age:
             LOG.debug(
-                f"Found potential volume backup for retention: Backup ID: {backup.backup_id} "
-                f"with backup age: {backup_age} (Default retention time: {self.threshold_strtime})."
+                "Found potential volume backup for retention: "
+                f"Backup ID: {backup.backup_id} "
+                f"with backup age: {backup_age} (Default retention "
+                f"time: {self.threshold_strtime})."
             )
             return True
         return False
@@ -263,9 +272,8 @@
                     )
 
                     # No way to judge retention
-                    if (
-                        self.threshold_strtime is None
-                        and not self.instance_retention_map
+                    if self.threshold_strtime is None and (
+                        not self.instance_retention_map
                     ):
                         return
                     backup_instance_map = {}
@@ -274,17 +282,19 @@
                     self.controller.update_project_list()
 
                     for backup in self.get_backup_list():
-                        # Create backup instance map for later sorted by created_at.
-                        # This can be use as base of judgement on delete a backup.
-                        # The reason we need such list is because backup have
-                        # dependency with each other after we enable incremental backup.
+                        # Create backup instance map for later sorted by
+                        # created_at. This can be use as base of judgement
+                        # on delete a backup. The reason we need such list
+                        # is because backup have dependency with each other
+                        # after we enable incremental backup.
                         # So we need to have information to judge on.
                         if backup.instance_id in backup_instance_map:
                             backup_instance_map[backup.instance_id].append(backup)
                         else:
                             backup_instance_map[backup.instance_id] = [backup]
 
-                    # Sort backup instance map and use it to check backup create time and order.
+                    # Sort backup instance map and use it to check backup
+                    # create time and order.
                     for instance_id in backup_instance_map:
                         sorted_backup_list = sorted(
                             backup_instance_map[instance_id],
@@ -294,9 +304,11 @@
                         for backup in sorted_backup_list:
                             if self.is_retention(backup):
                                 LOG.debug(
-                                    f"Retention: Try to remove volume backup {backup.backup_id}"
+                                    "Retention: Try to remove volume backup "
+                                    f"{backup.backup_id}"
                                 )
-                                # Try to delete and skip any incremental exist error.
+                                # Try to delete and skip any incremental
+                                # exist error.
                                 self.controller.hard_remove_volume_backup(
                                     backup, skip_inc_err=True
                                 )
@@ -319,7 +331,8 @@
             LOG.info(
                 _(
                     "Retention time format is invalid. "
-                    "Follow <YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>h<MINUTES>min<SECONDS>s."
+                    "Follow <YEARS>y<MONTHS>m<WEEKS>w<DAYS>d<HOURS>h"
+                    "<MINUTES>min<SECONDS>s."
                 )
             )
             return None
diff --git a/staffeln/conductor/result.py b/staffeln/conductor/result.py
index 34d9660..6bc24f5 100644
--- a/staffeln/conductor/result.py
+++ b/staffeln/conductor/result.py
@@ -1,12 +1,14 @@
 # Email notification package
 # This should be upgraded by integrating with mail server to send batch
-import staffeln.conf
+from __future__ import annotations
+
 from oslo_log import log
 from oslo_utils import timeutils
+
+import staffeln.conf
 from staffeln import objects
 from staffeln.common import constants, email
 from staffeln.common import time as xtime
-from staffeln.i18n import _
 
 CONF = staffeln.conf.CONF
 LOG = log.getLogger(__name__)
@@ -42,13 +44,15 @@
                 )
                 if not receiver:
                     LOG.warn(
-                        f"No email can be found from members of project {project_id}. "
+                        "No email can be found from members of project "
+                        f"{project_id}. "
                         "Skip report now and will try to report later."
                     )
                     return False
             except Exception as ex:
                 LOG.warn(
-                    f"Failed to fetch emails from project members with exception: {str(ex)} "
+                    "Failed to fetch emails from project members with "
+                    f"exception: {str(ex)} "
                     "As also no receiver email or project receiver domain are "
                     "configured. Will try to report later."
                 )
@@ -68,14 +72,12 @@
                 "smtp_server_port": CONF.notification.smtp_server_port,
             }
             email.send(smtp_profile)
-            LOG.info(_(f"Backup result email sent to {receiver}"))
+            LOG.info(f"Backup result email sent to {receiver}")
             return True
         except Exception as e:
             LOG.warn(
-                _(
-                    f"Backup result email send to {receiver} failed. "
-                    f"Please check email configuration. {str(e)}"
-                )
+                f"Backup result email send to {receiver} failed. "
+                f"Please check email configuration. {str(e)}"
             )
             raise
 
@@ -122,8 +124,10 @@
             success_volumes = "<br>".join(
                 [
                     (
-                        f"Volume ID: {str(e.volume_id)}, Backup ID: {str(e.backup_id)}, "
-                        f"Backup mode: {'Incremental' if e.incremental else 'Full'}, "
+                        f"Volume ID: {str(e.volume_id)}, "
+                        f"Backup ID: {str(e.backup_id)}, "
+                        "Backup mode: "
+                        f"{'Incremental' if e.incremental else 'Full'}, "
                         f"Created at: {str(e.created_at)}, Last updated at: "
                         f"{str(e.updated_at)}"
                     )
@@ -136,7 +140,8 @@
             failed_volumes = "<br>".join(
                 [
                     (
-                        f"Volume ID: {str(e.volume_id)}, Reason: {str(e.reason)}, "
+                        f"Volume ID: {str(e.volume_id)}, "
+                        f"Reason: {str(e.reason)}, "
                         f"Created at: {str(e.created_at)}, Last updated at: "
                         f"{str(e.updated_at)}"
                     )
@@ -148,8 +153,10 @@
         html += (
             f"<h3>Project: {project_name} (ID: {project_id})</h3>"
             "<h3>Quota Usage (Backup Gigabytes)</h3>"
-            f"<FONT COLOR={quota_color}><h4>Limit: {str(quota['limit'])} GB, In Use: "
-            f"{str(quota['in_use'])} GB, Reserved: {str(quota['reserved'])} GB, Total "
+            f"<FONT COLOR={quota_color}><h4>Limit: {str(quota['limit'])} "
+            "GB, In Use: "
+            f"{str(quota['in_use'])} GB, Reserved: {str(quota['reserved'])} "
+            "GB, Total "
             f"rate: {str(quota_usage)}</h4></FONT>"
             "<h3>Success List</h3>"
             f"<FONT COLOR=GREEN><h4>{success_volumes}</h4></FONT><br>"
@@ -165,5 +172,4 @@
             # Record success report
             self.create_report_record()
             return True
-        else:
-            return False
+        return False
diff --git a/staffeln/conf/__init__.py b/staffeln/conf/__init__.py
index 3289b63..76c247e 100755
--- a/staffeln/conf/__init__.py
+++ b/staffeln/conf/__init__.py
@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 from oslo_config import cfg
+
 from staffeln.conf import api, conductor, database, notify, paths
 
 CONF = cfg.CONF
diff --git a/staffeln/conf/api.py b/staffeln/conf/api.py
index e405d6a..4f848eb 100755
--- a/staffeln/conf/api.py
+++ b/staffeln/conf/api.py
@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 from oslo_config import cfg
+
 from staffeln.i18n import _
 
 api_group = cfg.OptGroup(
diff --git a/staffeln/conf/conductor.py b/staffeln/conf/conductor.py
index ab8e258..86407cc 100755
--- a/staffeln/conf/conductor.py
+++ b/staffeln/conf/conductor.py
@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 from oslo_config import cfg
+
 from staffeln.common import constants
 from staffeln.i18n import _
 
@@ -43,7 +46,8 @@
         "backup_cycle_timout",
         regex=(
             r"((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?"
-            r"((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?"
+            r"((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?"
+            r"((?P<seconds>\d+?)s)?"
         ),
         default=constants.DEFAULT_BACKUP_CYCLE_TIMEOUT,
         help=_(
@@ -58,7 +62,8 @@
     cfg.StrOpt(
         "retention_metadata_key",
         help=_(
-            "The key string of metadata the VM, which use as backup retention period."
+            "The key string of metadata the VM, which use as backup retention "
+            "period."
         ),
     ),
     cfg.IntOpt(
@@ -96,7 +101,8 @@
         "retention_time",
         regex=(
             r"((?P<years>\d+?)y)?((?P<months>\d+?)mon)?((?P<weeks>\d+?)w)?"
-            r"((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?((?P<seconds>\d+?)s)?"
+            r"((?P<days>\d+?)d)?((?P<hours>\d+?)h)?((?P<minutes>\d+?)min)?"
+            r"((?P<seconds>\d+?)s)?"
         ),
         default="2w3d",
         help=_(
@@ -110,13 +116,17 @@
 coordination_group = cfg.OptGroup(
     "coordination",
     title="Coordination Options",
-    help=_("Options under this group are used to define Coordination's configuration."),
+    help=_(
+        "Options under this group are used to define Coordination's" "configuration."
+    ),
 )
 
 
 coordination_opts = [
     cfg.StrOpt(
-        "backend_url", default="", help=_("lock coordination connection backend URL.")
+        "backend_url",
+        default="",
+        help=_("lock coordination connection backend URL."),
     ),
 ]
 
diff --git a/staffeln/conf/database.py b/staffeln/conf/database.py
index 761aa15..aa65873 100644
--- a/staffeln/conf/database.py
+++ b/staffeln/conf/database.py
@@ -1,5 +1,8 @@
+from __future__ import annotations
+
 from oslo_config import cfg
 from oslo_db import options as oslo_db_options
+
 from staffeln.conf import paths
 from staffeln.i18n import _
 
diff --git a/staffeln/conf/notify.py b/staffeln/conf/notify.py
index 21c67e8..c0834b1 100644
--- a/staffeln/conf/notify.py
+++ b/staffeln/conf/notify.py
@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 from oslo_config import cfg
+
 from staffeln.i18n import _
 
 notify_group = cfg.OptGroup(
@@ -32,7 +35,8 @@
             "The user name to authenticate with."
         ),
     ),
-    # We can remove the sender password as we are using postfix to send mail and we won't be authenticating.
+    # We can remove the sender password as we are using postfix to send
+    # mail and we won't be authenticating.
     cfg.StrOpt(
         "sender_pwd",
         help=_(
diff --git a/staffeln/conf/paths.py b/staffeln/conf/paths.py
index 7dbd9a1..08cf205 100644
--- a/staffeln/conf/paths.py
+++ b/staffeln/conf/paths.py
@@ -1,6 +1,9 @@
+from __future__ import annotations
+
 import os
 
 from oslo_config import cfg
+
 from staffeln.i18n import _
 
 PATH_OPTS = [
diff --git a/staffeln/db/api.py b/staffeln/db/api.py
index 2d10a05..5f6d2f8 100644
--- a/staffeln/db/api.py
+++ b/staffeln/db/api.py
@@ -1,4 +1,7 @@
 """Base classes for storage engines"""
+
+from __future__ import annotations
+
 from oslo_config import cfg
 from oslo_db import api as db_api
 
diff --git a/staffeln/db/base.py b/staffeln/db/base.py
index de0d7c3..ad303d1 100755
--- a/staffeln/db/base.py
+++ b/staffeln/db/base.py
@@ -1,5 +1,7 @@
 """Database setup and migration commands."""
 
+from __future__ import annotations
+
 
 class base:
     def __init__(self):
diff --git a/staffeln/db/migration.py b/staffeln/db/migration.py
index 113116e..0d6eea9 100644
--- a/staffeln/db/migration.py
+++ b/staffeln/db/migration.py
@@ -1,7 +1,11 @@
 """Database setup command"""
-import staffeln.conf
+
+from __future__ import annotations
+
 from stevedore import driver
 
+import staffeln.conf
+
 CONF = staffeln.conf.CONF
 
 _IMPL = None
diff --git a/staffeln/db/sqlalchemy/alembic/env.py b/staffeln/db/sqlalchemy/alembic/env.py
index 71461fe..18b6ee4 100644
--- a/staffeln/db/sqlalchemy/alembic/env.py
+++ b/staffeln/db/sqlalchemy/alembic/env.py
@@ -9,10 +9,12 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
+from __future__ import annotations
 
 from logging import config as log_config
 
 from alembic import context
+
 from staffeln.db.sqlalchemy import api as sqla_api
 from staffeln.db.sqlalchemy import models
 
diff --git a/staffeln/db/sqlalchemy/alembic/versions/041d9a0f1159_backup_add_names.py b/staffeln/db/sqlalchemy/alembic/versions/041d9a0f1159_backup_add_names.py
index a16f27c..492009c 100644
--- a/staffeln/db/sqlalchemy/alembic/versions/041d9a0f1159_backup_add_names.py
+++ b/staffeln/db/sqlalchemy/alembic/versions/041d9a0f1159_backup_add_names.py
@@ -7,6 +7,8 @@
 """
 
 # revision identifiers, used by Alembic.
+from __future__ import annotations
+
 revision = "041d9a0f1159"
 down_revision = ""
 
@@ -16,8 +18,10 @@
 
 def upgrade():
     op.add_column(
-        "queue_data", sa.Column("volume_name", sa.String(length=100), nullable=True)
+        "queue_data",
+        sa.Column("volume_name", sa.String(length=100), nullable=True),
     )
     op.add_column(
-        "queue_data", sa.Column("instance_name", sa.String(length=100), nullable=True)
+        "queue_data",
+        sa.Column("instance_name", sa.String(length=100), nullable=True),
     )
diff --git a/staffeln/db/sqlalchemy/alembic/versions/2b2b9df199bd_add_reason_column_to_queue_data_table.py b/staffeln/db/sqlalchemy/alembic/versions/2b2b9df199bd_add_reason_column_to_queue_data_table.py
index f78c91d..5f87464 100644
--- a/staffeln/db/sqlalchemy/alembic/versions/2b2b9df199bd_add_reason_column_to_queue_data_table.py
+++ b/staffeln/db/sqlalchemy/alembic/versions/2b2b9df199bd_add_reason_column_to_queue_data_table.py
@@ -7,6 +7,8 @@
 """
 
 # revision identifiers, used by Alembic.
+from __future__ import annotations
+
 revision = "2b2b9df199bd"
 down_revision = "ebdbed01e9a7"
 
diff --git a/staffeln/db/sqlalchemy/alembic/versions/5b2e78435231_add_report_timestamp.py b/staffeln/db/sqlalchemy/alembic/versions/5b2e78435231_add_report_timestamp.py
index 1abed60..20605ee 100644
--- a/staffeln/db/sqlalchemy/alembic/versions/5b2e78435231_add_report_timestamp.py
+++ b/staffeln/db/sqlalchemy/alembic/versions/5b2e78435231_add_report_timestamp.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import sqlalchemy as sa
 from alembic import op
 from oslo_log import log
@@ -21,7 +23,11 @@
     op.create_table(
         "report_timestamp",
         sa.Column(
-            "id", sa.String(36), primary_key=True, nullable=False, autoincrement=True
+            "id",
+            sa.String(36),
+            primary_key=True,
+            nullable=False,
+            autoincrement=True,
         ),
         sa.Column("created_at", sa.DateTime),
         sa.Column("updated_at", sa.DateTime),
diff --git a/staffeln/db/sqlalchemy/alembic/versions/ebdbed01e9a7_added_incremental_field.py b/staffeln/db/sqlalchemy/alembic/versions/ebdbed01e9a7_added_incremental_field.py
index b2ed161..8dccd8b 100644
--- a/staffeln/db/sqlalchemy/alembic/versions/ebdbed01e9a7_added_incremental_field.py
+++ b/staffeln/db/sqlalchemy/alembic/versions/ebdbed01e9a7_added_incremental_field.py
@@ -7,6 +7,8 @@
 """
 
 # revision identifiers, used by Alembic.
+from __future__ import annotations
+
 revision = "ebdbed01e9a7"
 down_revision = "041d9a0f1159"
 
diff --git a/staffeln/db/sqlalchemy/api.py b/staffeln/db/sqlalchemy/api.py
index 3cda5e7..b27d0d1 100644
--- a/staffeln/db/sqlalchemy/api.py
+++ b/staffeln/db/sqlalchemy/api.py
@@ -1,5 +1,7 @@
 """SQLAlchemy storage backend."""
 
+from __future__ import annotations
+
 import datetime
 import operator
 
@@ -11,6 +13,7 @@
 from oslo_utils import strutils, timeutils, uuidutils
 from sqlalchemy.inspection import inspect
 from sqlalchemy.orm import exc
+
 from staffeln.common import short_id
 from staffeln.db.sqlalchemy import models
 
@@ -54,6 +57,7 @@
 
 def add_identity_filter(query, value):
     """Adds an identity filter to a query.
+
     Filters results by ID, if supplied value is a valid integer.
     Otherwise attempts to filter results by backup_id.
     :param query: Initial query to add filter to.
@@ -161,6 +165,7 @@
 
     def _add_filters(self, query, model, filters=None, plain_fields=None):
         """Add filters while listing the columns from database table"""
+
         # timestamp_mixin_fields = ["created_at", "updated_at"]
         filters = filters or {}
 
@@ -180,7 +185,7 @@
         if (
             fieldname != "deleted"
             and value
-            and field.type.python_type is datetime.datetime
+            and (field.type.python_type is datetime.datetime)
         ):
             if not isinstance(value, datetime.datetime):
                 value = timeutils.parse_isotime(value)
@@ -288,7 +293,7 @@
 
         try:
             return self._update(models.Backup_data, backup_id, values)
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("backup resource not found.")
 
     def create_queue(self, values):
@@ -310,7 +315,7 @@
 
         try:
             return self._update(models.Queue_data, id, values)
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("Queue resource not found.")
 
     def get_queue_by_id(self, context, id):
@@ -323,15 +328,18 @@
         try:
 
             return self._get(
-                context, model=models.Queue_data, fieldname=fieldname, value=value
+                context,
+                model=models.Queue_data,
+                fieldname=fieldname,
+                value=value,
             )
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("Queue not found")
 
     def soft_delete_queue(self, id):
         try:
             return self._soft_delete(models.Queue_data, id)
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("Queue Not found.")
 
     def get_backup_by_backup_id(self, context, backup_id):
@@ -339,7 +347,7 @@
 
         try:
             return self._get_backup(context, fieldname="backup_id", value=backup_id)
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("Backup not found with backup_id %s." % backup_id)
 
     def _get_backup(self, context, fieldname, value):
@@ -347,15 +355,18 @@
 
         try:
             return self._get(
-                context, model=models.Backup_data, fieldname=fieldname, value=value
+                context,
+                model=models.Backup_data,
+                fieldname=fieldname,
+                value=value,
             )
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("Backup resource not found.")
 
     def soft_delete_backup(self, id):
         try:
             return self._soft_delete(models.Backup_data, id)
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("Backup Not found.")
 
     def get_report_timestamp_list(self, *args, **kwargs):
@@ -374,11 +385,11 @@
 
         try:
             return self._update(models.Report_timestamp, id, values)
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("Report Timestamp resource not found.")
 
     def soft_delete_report_timestamp(self, id):
         try:
             return self._soft_delete(models.Report_timestamp, id)
-        except:  # noqa: E722
+        except Exception:  # noqa: E722
             LOG.error("Report Timestamp Not found.")
diff --git a/staffeln/db/sqlalchemy/migration.py b/staffeln/db/sqlalchemy/migration.py
index 3a34c2b..e50d757 100644
--- a/staffeln/db/sqlalchemy/migration.py
+++ b/staffeln/db/sqlalchemy/migration.py
@@ -1,7 +1,10 @@
+from __future__ import annotations
+
 import os
 
-import staffeln.conf
 from oslo_db.sqlalchemy.migration_cli import manager
+
+import staffeln.conf
 from staffeln.db.sqlalchemy import api as sqla_api
 from staffeln.db.sqlalchemy import models
 
diff --git a/staffeln/db/sqlalchemy/models.py b/staffeln/db/sqlalchemy/models.py
index c186ddc..a0e3815 100644
--- a/staffeln/db/sqlalchemy/models.py
+++ b/staffeln/db/sqlalchemy/models.py
@@ -1,11 +1,15 @@
 """
 SQLAlchemy models for staffeln service
 """
+
+from __future__ import annotations
+
 import urllib.parse as urlparse
 
 from oslo_db.sqlalchemy import models
 from sqlalchemy import Boolean, Column, Integer, String, UniqueConstraint
 from sqlalchemy.ext.declarative import declarative_base
+
 from staffeln import conf
 
 CONF = conf.CONF
@@ -14,7 +18,10 @@
 def table_args():
     engine_name = urlparse.urlparse(CONF.database.connection).scheme
     if engine_name == "mysql":
-        return {"mysql_engine": CONF.database.mysql_engine, "mysql_charset": "utf8"}
+        return {
+            "mysql_engine": CONF.database.mysql_engine,
+            "mysql_charset": "utf8",
+        }
     return None
 
 
diff --git a/staffeln/exception.py b/staffeln/exception.py
index e561506..e1caceb 100644
--- a/staffeln/exception.py
+++ b/staffeln/exception.py
@@ -13,10 +13,10 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-
 """Staffeln base exception handling."""
+from __future__ import annotations
 
-from typing import Optional, Union  # noqa: H301
+from typing import Optional, Union
 
 from oslo_log import log as logging
 
diff --git a/staffeln/i18n.py b/staffeln/i18n.py
index 09fe8aa..cbef6e5 100755
--- a/staffeln/i18n.py
+++ b/staffeln/i18n.py
@@ -2,6 +2,8 @@
 See http://docs.openstack.org/developer/oslo.i18n/usage.html .
 """
 
+from __future__ import annotations
+
 import oslo_i18n
 
 DOMAIN = "staffeln"
diff --git a/staffeln/objects/__init__.py b/staffeln/objects/__init__.py
index 2af8df0..defa200 100755
--- a/staffeln/objects/__init__.py
+++ b/staffeln/objects/__init__.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from .queue import Queue  # noqa: F401
 from .report import ReportTimestamp  # noqa: F401
 from .volume import Volume  # noqa: F401
diff --git a/staffeln/objects/base.py b/staffeln/objects/base.py
index 8dd6f94..7f3cb85 100755
--- a/staffeln/objects/base.py
+++ b/staffeln/objects/base.py
@@ -1,8 +1,11 @@
 """Staffeln common internal object model"""
 
+from __future__ import annotations
+
 from oslo_utils import versionutils
 from oslo_versionedobjects import base as ovoo_base
 from oslo_versionedobjects import fields as ovoo_fields
+
 from staffeln import objects
 
 remotable_classmethod = ovoo_base.remotable_classmethod
@@ -50,7 +53,7 @@
     def obj_refresh(self, loaded_object):
         fields = (field for field in self.fields if field not in self.object_fields)
         for field in fields:
-            if self.obj_attr_is_set(field) and self[field] != loaded_object[field]:
+            if self.obj_attr_is_set(field) and (self[field] != loaded_object[field]):
                 self[field] = loaded_object[field]
 
     @staticmethod
diff --git a/staffeln/objects/fields.py b/staffeln/objects/fields.py
index 3f6c2a7..95ed59c 100644
--- a/staffeln/objects/fields.py
+++ b/staffeln/objects/fields.py
@@ -1,4 +1,7 @@
 """Utility method for objects"""
+
+from __future__ import annotations
+
 from oslo_serialization import jsonutils
 from oslo_versionedobjects import fields
 
diff --git a/staffeln/objects/queue.py b/staffeln/objects/queue.py
index db49c21..b80c2d8 100644
--- a/staffeln/objects/queue.py
+++ b/staffeln/objects/queue.py
@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 from oslo_versionedobjects import fields as ovoo_fields
+
 from staffeln.db import api as db_api
 from staffeln.objects import base
 from staffeln.objects import fields as sfeild
@@ -6,7 +9,9 @@
 
 @base.StaffelnObjectRegistry.register
 class Queue(
-    base.StaffelnPersistentObject, base.StaffelnObject, base.StaffelnObjectDictCompat
+    base.StaffelnPersistentObject,
+    base.StaffelnObject,
+    base.StaffelnObjectDictCompat,
 ):
     VERSION = "1.2"
     # Version 1.0: Initial version
@@ -37,6 +42,7 @@
     @base.remotable_classmethod
     def get_by_id(cls, context, id):  # pylint: disable=E0213
         """Find a queue task based on id
+
         :param context: Security context. NOTE: This should only
                         be used internally by the indirection_api.
                         Unfortunately, RPC requires context as the first
@@ -46,6 +52,7 @@
         :param backup_id: the backup id of volume in queue.
         :returns: a :class:`Queue` object.
         """
+
         db_queue = cls.dbapi.get_queue_by_id(context, id)
         queue = cls._from_db_object(cls(context), db_queue)
         return queue
@@ -53,6 +60,7 @@
     @base.remotable
     def create(self):
         """Create a :class:`Backup_data` record in the DB"""
+
         values = self.obj_get_changes()
         db_queue = self.dbapi.create_queue(values)
         return self._from_db_object(self, db_queue)
@@ -73,4 +81,5 @@
     @base.remotable
     def delete_queue(self):
         """Soft Delete the :class:`Queue_data` from the DB"""
+
         self.dbapi.soft_delete_queue(self.id)
diff --git a/staffeln/objects/report.py b/staffeln/objects/report.py
index e851a93..588be73 100644
--- a/staffeln/objects/report.py
+++ b/staffeln/objects/report.py
@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 from oslo_versionedobjects import fields as ovoo_fields
+
 from staffeln.db import api as db_api
 from staffeln.objects import base
 from staffeln.objects import fields as sfeild
@@ -6,7 +9,9 @@
 
 @base.StaffelnObjectRegistry.register
 class ReportTimestamp(
-    base.StaffelnPersistentObject, base.StaffelnObject, base.StaffelnObjectDictCompat
+    base.StaffelnPersistentObject,
+    base.StaffelnObject,
+    base.StaffelnObjectDictCompat,
 ):
     VERSION = "1.0"
     # Version 1.0: Initial version
diff --git a/staffeln/objects/volume.py b/staffeln/objects/volume.py
index a4f24f6..f8b6e80 100644
--- a/staffeln/objects/volume.py
+++ b/staffeln/objects/volume.py
@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 from oslo_versionedobjects import fields as ovoo_fields
+
 from staffeln.db import api as db_api
 from staffeln.objects import base
 from staffeln.objects import fields as sfeild
@@ -6,7 +9,9 @@
 
 @base.StaffelnObjectRegistry.register
 class Volume(
-    base.StaffelnPersistentObject, base.StaffelnObject, base.StaffelnObjectDictCompat
+    base.StaffelnPersistentObject,
+    base.StaffelnObject,
+    base.StaffelnObjectDictCompat,
 ):
     VERSION = "1.1"
     # Version 1.0: Initial version
@@ -58,6 +63,7 @@
     @base.remotable
     def refresh(self):
         """Loads updates for this :class:`Backup_data`.
+
         Loads a backup with the same backup_id from the database and
         checks for updated attributes. Updates are applied from
         the loaded backup column by column, if there are any updates.
@@ -73,6 +79,7 @@
     @base.remotable_classmethod
     def get_backup_by_backup_id(cls, context, backup_id):  # pylint: disable=E0213
         """Find a backup based on backup_id
+
         :param context: Security context. NOTE: This should only
                         be used internally by the indirection_api.
                         Unfortunately, RPC requires context as the first
diff --git a/staffeln/tests/base.py b/staffeln/tests/base.py
index 1c30cdb..00059c0 100755
--- a/staffeln/tests/base.py
+++ b/staffeln/tests/base.py
@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-
 # Copyright 2010-2011 OpenStack Foundation
 # Copyright (c) 2013 Hewlett-Packard Development Company, L.P.
 #
@@ -14,10 +13,10 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
+from __future__ import annotations
 
 from oslotest import base
 
 
 class TestCase(base.BaseTestCase):
-
     """Test case base class for all unit tests."""
diff --git a/staffeln/tests/common/test_openstacksdk.py b/staffeln/tests/common/test_openstacksdk.py
new file mode 100644
index 0000000..ceeece9
--- /dev/null
+++ b/staffeln/tests/common/test_openstacksdk.py
@@ -0,0 +1,458 @@
+# SPDX-License-Identifier: Apache-2.0
+from __future__ import annotations
+
+from unittest import mock
+
+import tenacity
+from openstack import exceptions as openstack_exc
+
+from staffeln import conf
+from staffeln.common import openstack as s_openstack
+from staffeln.tests import base
+
+
+class OpenstackSDKTest(base.TestCase):
+
+    def setUp(self):
+        super(OpenstackSDKTest, self).setUp()
+        self.m_c = mock.MagicMock()
+        with mock.patch("openstack.connect", return_value=self.m_c):
+            self.openstack = s_openstack.OpenstackSDK()
+        self.m_sleep = mock.Mock()
+        func_list = [
+            "get_user_id",
+            "get_projects",
+            "get_servers",
+            "get_role_assignments",
+            "get_user",
+            "get_project_member_emails",
+            "get_volume",
+            "get_backup",
+            "delete_backup",
+            "get_backup_quota",
+            "get_backup_gigabytes_quota",
+        ]
+        for i in func_list:
+            getattr(self.openstack, i).retry.sleep = (  # pylint: disable=E1101
+                self.m_sleep
+            )
+            getattr(self.openstack, i).retry.stop = (  # pylint: disable=E1101
+                tenacity.stop_after_attempt(2)
+            )
+
+        self.fake_user = mock.MagicMock(id="foo", email="foo@foo.com")
+        self.fake_volume = mock.MagicMock(id="fake_volume")
+        self.fake_backup = mock.MagicMock(id="fake_backup")
+        self.fake_role_assignment = mock.MagicMock(user="foo")
+        self.fake_role_assignment2 = mock.MagicMock(user={"id": "bar"})
+
+    def _test_http_error(self, m_func, retry_func, status_code, call_count=1, **kwargs):
+        m_func.side_effect = openstack_exc.HttpException(http_status=status_code)
+        exc = self.assertRaises(
+            openstack_exc.HttpException,
+            getattr(self.openstack, retry_func),
+            **kwargs,
+        )
+        self.assertEqual(status_code, exc.status_code)
+        skip_retry_codes = conf.CONF.openstack.skip_retry_codes.replace(" ", "").split(
+            ","
+        )
+        if str(status_code) not in skip_retry_codes:
+            if call_count == 1:
+                self.m_sleep.assert_called_once_with(1.0)
+            else:
+                self.m_sleep.assert_has_calls(
+                    [mock.call(1.0) for c in range(call_count)]
+                )
+        else:
+            self.m_sleep.assert_not_called()
+
+    def _test_non_http_error(self, m_func, retry_func, **kwargs):
+        m_func.side_effect = KeyError
+        self.assertRaises(KeyError, getattr(self.openstack, retry_func), **kwargs)
+        self.m_sleep.assert_not_called()
+
+    def test_get_servers(self):
+        self.m_c.compute.servers = mock.MagicMock(return_value=[])
+        self.assertEqual(self.openstack.get_servers(), [])
+        self.m_c.compute.servers.assert_called_once_with(
+            details=True, all_projects=True
+        )
+
+    def test_get_servers_non_http_error(self):
+        self._test_non_http_error(self.m_c.compute.servers, "get_servers")
+
+    def test_get_servers_conf_skip_http_error(self):
+        conf.CONF.set_override("skip_retry_codes", "403,", "openstack")
+        self._test_http_error(self.m_c.compute.servers, "get_servers", status_code=403)
+        self.assertEqual("403,", conf.CONF.openstack.skip_retry_codes)
+
+    def test_get_servers_conf_skip_http_error_not_hit(self):
+        conf.CONF.set_override("skip_retry_codes", "403,", "openstack")
+        self._test_http_error(self.m_c.compute.servers, "get_servers", status_code=404)
+        self.assertEqual("403,", conf.CONF.openstack.skip_retry_codes)
+
+    def test_get_servers_404_http_error(self):
+        self._test_http_error(self.m_c.compute.servers, "get_servers", status_code=404)
+
+    def test_get_servers_500_http_error(self):
+        self._test_http_error(self.m_c.compute.servers, "get_servers", status_code=500)
+
+    def test_get_projects(self):
+        self.m_c.list_projects = mock.MagicMock(return_value=[])
+        self.assertEqual(self.openstack.get_projects(), [])
+        self.m_c.list_projects.assert_called_once_with()
+
+    def test_get_projects_non_http_error(self):
+        self._test_non_http_error(self.m_c.list_projects, "get_projects")
+
+    def test_get_projects_404_http_error(self):
+        self._test_http_error(self.m_c.list_projects, "get_projects", status_code=404)
+
+    def test_get_projects_500_http_error(self):
+        self._test_http_error(self.m_c.list_projects, "get_projects", status_code=500)
+
+    def test_get_user_id(self):
+        self.m_c.get_user = mock.MagicMock(return_value=self.fake_user)
+        self.assertEqual(self.openstack.get_user_id(), "foo")
+        self.m_c.get_user.assert_called_once_with(name_or_id=mock.ANY)
+
+    def test_get_user_id_non_http_error(self):
+        self._test_non_http_error(self.m_c.get_user, "get_user_id")
+
+    def test_get_user_id_404_http_error(self):
+        self._test_http_error(self.m_c.get_user, "get_user_id", status_code=404)
+
+    def test_get_user_id_500_http_error(self):
+        self._test_http_error(self.m_c.get_user, "get_user_id", status_code=500)
+
+    def test_get_user(self):
+        self.m_c.get_user = mock.MagicMock(return_value=self.fake_user)
+        self.assertEqual(
+            self.openstack.get_user(user_id=self.fake_user.id), self.fake_user
+        )
+        self.m_c.get_user.assert_called_once_with(name_or_id=self.fake_user.id)
+
+    def test_get_user_non_http_error(self):
+        self._test_non_http_error(
+            self.m_c.get_user, "get_user", user_id=self.fake_user.id
+        )
+
+    def test_get_user_404_http_error(self):
+        self._test_http_error(
+            self.m_c.get_user,
+            "get_user",
+            status_code=404,
+            user_id=self.fake_user.id,
+        )
+
+    def test_get_user_500_http_error(self):
+        self._test_http_error(
+            self.m_c.get_user,
+            "get_user",
+            status_code=500,
+            user_id=self.fake_user.id,
+        )
+
+    def test_get_role_assignments(self):
+        self.m_c.list_role_assignments = mock.MagicMock(return_value=[])
+        self.assertEqual(self.openstack.get_role_assignments(project_id="foo"), [])
+        self.m_c.list_role_assignments.assert_called_once_with(
+            filters={"project": "foo"}
+        )
+
+    def test_get_role_assignments_non_http_error(self):
+        self._test_non_http_error(
+            self.m_c.list_role_assignments,
+            "get_role_assignments",
+            project_id="foo",
+        )
+
+    def test_get_role_assignments_404_http_error(self):
+        self._test_http_error(
+            self.m_c.list_role_assignments,
+            "get_role_assignments",
+            status_code=404,
+            project_id="foo",
+        )
+
+    def test_get_role_assignments_500_http_error(self):
+        self._test_http_error(
+            self.m_c.list_role_assignments,
+            "get_role_assignments",
+            status_code=500,
+            project_id="foo",
+        )
+
+    def test_get_project_member_emails(self):
+        # Make sure we cover both get_user pattern
+        self.m_c.list_role_assignments = mock.MagicMock(
+            return_value=[
+                self.fake_role_assignment,
+                self.fake_role_assignment2,
+            ]
+        )
+        self.m_c.get_user = mock.MagicMock(return_value=self.fake_user)
+        self.assertEqual(
+            self.openstack.get_project_member_emails(project_id="foo"),
+            [self.fake_user.email, self.fake_user.email],
+        )
+        self.m_c.list_role_assignments.assert_called_once_with(
+            filters={"project": "foo"}
+        )
+        self.m_c.get_user.assert_has_calls(
+            [
+                mock.call(name_or_id=self.fake_role_assignment.user),
+                mock.call(name_or_id=self.fake_role_assignment2.user.get("id")),
+            ]
+        )
+
+    def test_get_project_member_emails_non_http_error(self):
+        self._test_non_http_error(
+            self.m_c.list_role_assignments,
+            "get_project_member_emails",
+            project_id="foo",
+        )
+
+    def test_get_project_member_emails_404_http_error(self):
+        self._test_http_error(
+            self.m_c.list_role_assignments,
+            "get_project_member_emails",
+            status_code=404,
+            project_id="foo",
+        )
+
+    def test_get_project_member_emails_500_http_error(self):
+        self._test_http_error(
+            self.m_c.list_role_assignments,
+            "get_project_member_emails",
+            status_code=500,
+            call_count=3,
+            project_id="foo",
+        )
+
+    def test_get_volume(self):
+        self.m_c.get_volume_by_id = mock.MagicMock(return_value=self.fake_volume)
+        self.assertEqual(
+            self.openstack.get_volume(uuid=self.fake_volume.id, project_id="bar"),
+            self.fake_volume,
+        )
+        self.m_c.get_volume_by_id.assert_called_once_with(self.fake_volume.id)
+
+    def test_get_volume_non_http_error(self):
+        self._test_non_http_error(
+            self.m_c.get_volume_by_id,
+            "get_volume",
+            uuid="foo",
+            project_id="bar",
+        )
+
+    def test_get_volume_404_http_error(self):
+        self._test_http_error(
+            self.m_c.get_volume_by_id,
+            "get_volume",
+            status_code=404,
+            uuid="foo",
+            project_id="bar",
+        )
+
+    def test_get_volume_500_http_error(self):
+        self._test_http_error(
+            self.m_c.get_volume_by_id,
+            "get_volume",
+            status_code=500,
+            uuid="foo",
+            project_id="bar",
+        )
+
+    def test_get_backup(self):
+        self.m_c.get_volume_backup = mock.MagicMock(return_value=self.fake_backup)
+        self.assertEqual(
+            self.openstack.get_backup(uuid=self.fake_backup.id, project_id="bar"),
+            self.fake_backup,
+        )
+        self.m_c.get_volume_backup.assert_called_once_with(self.fake_backup.id)
+
+    def test_get_backup_not_found(self):
+        self.m_c.get_volume_backup = mock.MagicMock(
+            side_effect=openstack_exc.ResourceNotFound
+        )
+        self.assertEqual(
+            self.openstack.get_backup(uuid=self.fake_backup.id, project_id="bar"),
+            None,
+        )
+        self.m_c.get_volume_backup.assert_called_once_with(self.fake_backup.id)
+
+    def test_get_backup_non_http_error(self):
+        self._test_non_http_error(
+            self.m_c.get_volume_backup,
+            "get_backup",
+            uuid="foo",
+            project_id="bar",
+        )
+
+    def test_get_backup_404_http_error(self):
+        self._test_http_error(
+            self.m_c.get_volume_backup,
+            "get_backup",
+            status_code=404,
+            uuid="foo",
+            project_id="bar",
+        )
+
+    def test_get_backup_500_http_error(self):
+        self._test_http_error(
+            self.m_c.get_volume_backup,
+            "get_backup",
+            status_code=500,
+            uuid="foo",
+            project_id="bar",
+        )
+
+    def test_delete_backup(self):
+        self.m_c.delete_volume_backup = mock.MagicMock(return_value=self.fake_backup)
+        self.assertEqual(
+            self.openstack.delete_backup(uuid=self.fake_backup.id, project_id="bar"),
+            None,
+        )
+        self.m_c.delete_volume_backup.assert_called_once_with(
+            self.fake_backup.id, force=False
+        )
+
+    def test_delete_backup_not_found(self):
+        self.m_c.delete_volume_backup = mock.MagicMock(
+            side_effect=openstack_exc.ResourceNotFound
+        )
+        self.assertEqual(
+            self.openstack.delete_backup(uuid=self.fake_backup.id, project_id="bar"),
+            None,
+        )
+        self.m_c.delete_volume_backup.assert_called_once_with(
+            self.fake_backup.id, force=False
+        )
+
+    def test_delete_backup_non_http_error(self):
+        self._test_non_http_error(
+            self.m_c.delete_volume_backup,
+            "delete_backup",
+            uuid="foo",
+            project_id="bar",
+        )
+
+    def test_delete_backup_404_http_error(self):
+        self._test_http_error(
+            self.m_c.delete_volume_backup,
+            "delete_backup",
+            status_code=404,
+            uuid="foo",
+            project_id="bar",
+        )
+
+    def test_delete_backup_500_http_error(self):
+        self._test_http_error(
+            self.m_c.delete_volume_backup,
+            "delete_backup",
+            status_code=500,
+            uuid="foo",
+            project_id="bar",
+        )
+
+    @mock.patch("openstack.proxy._json_response")
+    def test_get_backup_quota(self, m_j_r):
+        self.m_c.block_storage.get = mock.MagicMock(status_code=200)
+        self.m_gam = mock.MagicMock()
+        self.m_c._get_and_munchify = self.m_gam
+        self.m_gam.return_value = mock.MagicMock(backups=[self.fake_backup.id])
+        self.assertEqual(
+            [self.fake_backup.id],
+            self.openstack.get_backup_quota(project_id="bar"),
+        )
+        self.m_c.block_storage.get.assert_called_once_with(
+            "/os-quota-sets/bar?usage=True"
+        )
+
+    def test_get_backup_quota_non_http_error(self):
+        self._test_non_http_error(
+            self.m_c.block_storage.get, "get_backup_quota", project_id="bar"
+        )
+
+    def test_get_backup_quota_404_http_error(self):
+        self._test_http_error(
+            self.m_c.block_storage.get,
+            "get_backup_quota",
+            status_code=404,
+            project_id="bar",
+        )
+
+    def test_get_backup_quota_500_http_error(self):
+        self._test_http_error(
+            self.m_c.block_storage.get,
+            "get_backup_quota",
+            status_code=500,
+            project_id="bar",
+        )
+
+    @mock.patch("openstack.proxy._json_response")
+    def test_get_backup_gigabytes_quota(self, m_j_r):
+        self.m_c.block_storage.get = mock.MagicMock(status_code=200)
+        self.m_gam = mock.MagicMock()
+        self.m_c._get_and_munchify = self.m_gam
+        self.m_gam.return_value = mock.MagicMock(backup_gigabytes=[self.fake_backup.id])
+        self.assertEqual(
+            [self.fake_backup.id],
+            self.openstack.get_backup_gigabytes_quota(project_id="bar"),
+        )
+        self.m_c.block_storage.get.assert_called_once_with(
+            "/os-quota-sets/bar?usage=True"
+        )
+
+    def test_get_backup_gigabytes_quota_non_http_error(self):
+        self._test_non_http_error(
+            self.m_c.block_storage.get,
+            "get_backup_gigabytes_quota",
+            project_id="bar",
+        )
+
+    def test_get_backup_gigabytes_quota_404_http_error(self):
+        self._test_http_error(
+            self.m_c.block_storage.get,
+            "get_backup_gigabytes_quota",
+            status_code=404,
+            project_id="bar",
+        )
+
+    def test_get_backup_gigabytes_quota_500_http_error(self):
+        self._test_http_error(
+            self.m_c.block_storage.get,
+            "get_backup_gigabytes_quota",
+            status_code=500,
+            project_id="bar",
+        )
+
+    @mock.patch("openstack.proxy._json_response")
+    def test_get_volume_quotas(self, m_j_r):
+        self.m_c.block_storage.get = mock.MagicMock(status_code=200)
+        self.m_gam_return = mock.MagicMock()
+        self.m_gam = mock.MagicMock(return_value=self.m_gam_return)
+        self.m_c._get_and_munchify = self.m_gam
+        self.assertEqual(
+            self.m_gam_return,
+            self.openstack._get_volume_quotas(project_id="bar"),
+        )
+        self.m_c.block_storage.get.assert_called_once_with(
+            "/os-quota-sets/bar?usage=True"
+        )
+        self.m_gam.assert_called_once_with("quota_set", m_j_r())
+
+    @mock.patch("openstack.proxy._json_response")
+    def test_get_volume_quotas_no_usage(self, m_j_r):
+        self.m_c.block_storage.get = mock.MagicMock(status_code=200)
+        self.m_gam_return = mock.MagicMock()
+        self.m_gam = mock.MagicMock(return_value=self.m_gam_return)
+        self.m_c._get_and_munchify = self.m_gam
+        self.assertEqual(
+            self.m_gam_return,
+            self.openstack._get_volume_quotas(project_id="bar", usage=False),
+        )
+        self.m_c.block_storage.get.assert_called_once_with("/os-quota-sets/bar")
+        self.m_gam.assert_called_once_with("quota_set", m_j_r())
diff --git a/staffeln/tests/test_staffeln.py b/staffeln/tests/test_staffeln.py
index 6c7c5f3..5ef2a92 100755
--- a/staffeln/tests/test_staffeln.py
+++ b/staffeln/tests/test_staffeln.py
@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
 # a copy of the License at
@@ -11,13 +10,13 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
-
 """
 test_staffeln
 ----------------------------------
 
 Tests for `staffeln` module.
 """
+from __future__ import annotations
 
 from staffeln.tests import base
 
diff --git a/staffeln/version.py b/staffeln/version.py
index efe79df..b943573 100755
--- a/staffeln/version.py
+++ b/staffeln/version.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import pbr.version
 
 version_info = pbr.version.VersionInfo("staffeln")
diff --git a/test-requirements.txt b/test-requirements.txt
index f09cf7f..2c28785 100755
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -9,3 +9,4 @@
 oslotest>=1.10.0 # Apache-2.0
 stestr>=1.0.0 # Apache-2.0
 testtools>=1.4.0 # MIT
+pre-commit
diff --git a/tox.ini b/tox.ini
index 4812539..2de6fda 100755
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py37,pep8
+envlist = py3,linters
 skipsdist = True
 sitepackages = False
 skip_missing_interpreters = True
@@ -12,7 +12,6 @@
    TERM=linux
 
 deps =
-    flake8
     -r{toxinidir}/test-requirements.txt
     -r{toxinidir}/requirements.txt
     -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
@@ -21,15 +20,11 @@
     pip install {opts} {packages}
 
 
-[testenv:py3]
+[testenv:{py3,py38,py39,py310}]
 basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
 commands = stestr run --slowest {posargs}
 
-[testenv:pep8]
-commands =   
-    flake8
-
 [testenv:cover]
 basepython = python3
 deps = -r{toxinidir}/requirements.txt
@@ -45,14 +40,12 @@
     coverage xml -o cover/coverage.xml
     coverage report
 
+[testenv:linters]
+skipsdist = True
+deps =
+  pre-commit
+commands =
+  pre-commit run --all-files --show-diff-on-failure
 
 [testenv:venv]
 commands = {posargs}
-
-[flake8]
-# E123, E125 skipped as they are invalid PEP-8.
-
-show-source = True
-ignore = E123,E125
-builtins = _
-exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
diff --git a/zuul.d/jobs.yaml b/zuul.d/jobs.yaml
new file mode 100644
index 0000000..d7e620d
--- /dev/null
+++ b/zuul.d/jobs.yaml
@@ -0,0 +1,9 @@
+- job:
+    name: staffeln-linters
+    parent: tox-linters
+
+- job:
+    name: staffeln-unit
+    parent: tox
+    vars:
+      tox_envlist: py3
diff --git a/zuul.d/project.yaml b/zuul.d/project.yaml
new file mode 100644
index 0000000..a62642a
--- /dev/null
+++ b/zuul.d/project.yaml
@@ -0,0 +1,9 @@
+- project:
+    check:
+      jobs:
+        - staffeln-linters
+        - staffeln-unit
+    gate:
+      jobs:
+        - staffeln-linters
+        - staffeln-unit