sunbeam-charms/ops-sunbeam/ops_sunbeam/job_ctrl.py
Guillaume Boutry 8c674de50e
[ops-sunbeam] Implement mypy linter
Implement mypy in the most non-breaking way possible. There's still some
changes of behavior that crept in, merely due to incorrect edge case
handling.

Charm libraries are generally well typed, include py.typed marker for
all of the libraries, to allow mypy analyzing their usage.

Change-Id: I7bda1913fa08dd4954a606526272ac80b45197cc
Signed-off-by: Guillaume Boutry <guillaume.boutry@canonical.com>
2024-08-13 18:56:33 +02:00

102 lines
2.9 KiB
Python

# Copyright 2023 Canonical Ltd.
#
# 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# 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.
"""Helpers for controlling whether jobs should run.
In general it is better for a command to be a noop if run when it is not
needed but in some cases the commands are expensive or disruptive in which
case these helpers can limit how frequently they are run.
"""
import logging
import time
import typing
from functools import (
wraps,
)
import ops.framework
if typing.TYPE_CHECKING:
import ops_sunbeam.charm
logger = logging.getLogger(__name__)
def run_once_per_unit(label):
"""Run once per instantiation of a unit.
This is designed for commands which only need to be run once on each
instantiation of a unit.
Note: This decorator can only be used within a charm derived from
ops_sunbeam.charm.OSBaseOperatorCharm.
Example usage:
class MyCharm(ops_sunbeam.charm.OSBaseOperatorCharm):
...
@run_once_per_unit('a2enmod')
def enable_apache_module(self):
check_call(['a2enmod', 'wsgi'])
"""
def wrap(f):
@wraps(f)
def wrapped_f(
charm: "ops_sunbeam.charm.OSBaseOperatorCharm", *args, **kwargs
):
"""Run once decorator.
:param charm: Instance of charm
"""
storage = LocalJobStorage(charm._state)
if label in storage:
logging.warning(
f"Not running {label}, it has run previously for this unit"
)
else:
logging.warning(
f"Running {label}, it has not run on this unit before"
)
f(charm, *args, **kwargs)
storage.add(label)
return wrapped_f
return wrap
class LocalJobStorage:
"""Class to store job info of jobs run on the local unit."""
def __init__(self, storage: ops.framework.BoundStoredState):
"""Setup job history storage."""
self.storage = storage
try:
self.storage.run_once
except AttributeError:
self.storage.run_once = {}
def get_labels(self):
"""Return all job entries."""
return self.storage.run_once
def __contains__(self, key):
"""Check if label is in list or run jobs."""
return key in self.get_labels().keys()
def add(self, key):
"""Add the label of job that has run."""
self.storage.run_once[key] = str(time.time())