mirror of
https://github.com/pretix/pretix.git
synced 2026-05-07 15:34:02 +00:00
85 lines
3.5 KiB
Python
85 lines
3.5 KiB
Python
#
|
|
# This file is part of pretix (Community Edition).
|
|
#
|
|
# Copyright (C) 2014-2020 Raphael Michel and contributors
|
|
# Copyright (C) 2020-2021 rami.io GmbH and contributors
|
|
#
|
|
# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
|
|
# Public License as published by the Free Software Foundation in version 3 of the License.
|
|
#
|
|
# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
|
|
# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
|
|
# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
|
|
# this file, see <https://pretix.eu/about/en/license>.
|
|
#
|
|
# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
|
|
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
|
|
# details.
|
|
#
|
|
# You should have received a copy of the GNU Affero General Public License along with this program. If not, see
|
|
# <https://www.gnu.org/licenses/>.
|
|
#
|
|
import logging
|
|
import uuid
|
|
from functools import wraps
|
|
|
|
from django.core.cache import cache
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
SKIPPED = object()
|
|
|
|
|
|
def minimum_interval(minutes_after_success, minutes_after_error=0, minutes_running_timeout=30):
|
|
"""
|
|
This is intended to be used as a decorator on receivers of the ``periodic_task`` signal.
|
|
It stores the result in the task in the cache (usually redis) to ensure the receiver function
|
|
isn't executed less than ``minutes_after_success`` after the last successful run and no less
|
|
than ``minutes_after_error`` after the last failed run. There's also a simple locking mechanism
|
|
implemented making sure the function is not called a second time while it is running, unless
|
|
``minutes_running_timeout`` have passed. This locking mechanism is naive and not safe of
|
|
race-conditions, it should not be relied upon.
|
|
"""
|
|
def deco(f):
|
|
@wraps(f)
|
|
def wrapper(*args, **kwargs):
|
|
key_running = f'pretix_periodic_{f.__module__}.{f.__name__}_running'
|
|
key_result = f'pretix_periodic_{f.__module__}.{f.__name__}_result'
|
|
|
|
running_val = cache.get(key_running)
|
|
if running_val:
|
|
# Currently running
|
|
return SKIPPED
|
|
|
|
result_val = cache.get(key_result)
|
|
if result_val:
|
|
# Has run recently
|
|
return SKIPPED
|
|
|
|
uniqid = str(uuid.uuid4())
|
|
cache.set(key_running, uniqid, timeout=minutes_running_timeout * 60)
|
|
try:
|
|
retval = f(*args, **kwargs)
|
|
except Exception as e:
|
|
try:
|
|
cache.set(key_result, 'error', timeout=minutes_after_error * 60)
|
|
except:
|
|
logger.exception('Could not store result')
|
|
raise e
|
|
else:
|
|
try:
|
|
cache.set(key_result, 'success', timeout=minutes_after_success * 60)
|
|
except:
|
|
logger.exception('Could not store result')
|
|
return retval
|
|
finally:
|
|
try:
|
|
if cache.get(key_running) == uniqid:
|
|
cache.delete(key_running)
|
|
except:
|
|
logger.exception('Could not release lock')
|
|
|
|
return wrapper
|
|
|
|
return deco
|