问题描述：
【celery的timezone设置对收集任务结果result_backend无效】python版本3.8，celery版本4.3.0，在使用redis收集任务结果时，发现redis中存储的任务结果和实际运行的时间对不上。代码如下：
# app.py
from celery import Celeryapp = Celery("elTask", broker="redis://:@192.168.10.21:6379/15", backend='celery.backends.redis.RedisBackend',
changes={"redis_host": "192.168.10.21", "redis_db": 14, 'timezone': 'Asia/Shanghai',
'CELERY_ENABLE_UTC': False})@app.task(name="funcname")
def async_funcname():
print("async function")
return Trueif __name__ == '__main__':
async_funcname.delay()解决方法：
仔细研究发现celery.backends.redis.RedisBackend这个类继承的celery.backends.base.BaseKeyValueStoreBackend类中实现的_store_result函数与任务结果时间有关，源代码如下：
def _store_result(self, task_id, result, state,
traceback=None, request=None, **kwargs):if state in self.READY_STATES:
date_done = datetime.datetime.utcnow()
else:
date_done = Nonemeta = {
'status': state,
'result': result,
'traceback': traceback,
'children': self.current_task_children(request),
'task_id': bytes_to_str(task_id),
'date_done': date_done,
}if request and getattr(request, 'group', None):
meta['group_id'] = request.group
if request and getattr(request, 'parent_id', None):
meta['parent_id'] = request.parent_idif self.app.conf.find_value_for_key('extended', 'result'):
if request:
request_meta = {
'name': getattr(request, 'task_name', None),
'args': getattr(request, 'args', None),
'kwargs': getattr(request, 'kwargs', None),
'worker': getattr(request, 'hostname', None),
'retries': getattr(request, 'retries', None),
'queue': request.delivery_info.get('routing_key')
if hasattr(request, 'delivery_info') and
request.delivery_info else None
}meta.update(request_meta)self.set(self.get_key_for_task(task_id), self.encode(meta))
return result代码中date_done就是收集到任务的时间。在解决问题的过程中发现在当前最新版本4.4.6中也存在这个问题，但是问题代码不同,在4.4.6版本中是celery.backends.base.Backend中的_get_result_meta方法和任务时间相关。我的解决办法是继承重写这个方法。代码如下：
# app.py
import datetime
from celery import Celery
from celery.utils.encoding import bytes_to_str
from celery.backends.redis import RedisBackendclass RedisResult(RedisBackend):
def _store_result(self, task_id, result, state,
traceback=None, request=None, **kwargs):if state in self.READY_STATES:
date_done = datetime.datetime.now()
else:
date_done = Nonemeta = {
'status': state,
'result': result,
'traceback': traceback,
'children': self.current_task_children(request),
'task_id': bytes_to_str(task_id),
'date_done': date_done,
}if request and getattr(request, 'group', None):
meta['group_id'] = request.group
if request and getattr(request, 'parent_id', None):
meta['parent_id'] = request.parent_idif self.app.conf.find_value_for_key('extended', 'result'):
if request:
request_meta = {
'name': getattr(request, 'task_name', None),
'args': getattr(request, 'args', None),
'kwargs': getattr(request, 'kwargs', None),
'worker': getattr(request, 'hostname', None),
'retries': getattr(request, 'retries', None),
'queue': request.delivery_info.get('routing_key')
if hasattr(request, 'delivery_info') and
request.delivery_info else None
}meta.update(request_meta)self.set(self.get_key_for_task(task_id), self.encode(meta))
return resultapp = Celery("elTask", broker="redis://:@192.168.10.21:6379/15", backend='app.RedisResult',
changes={"redis_host": "192.168.10.21", "redis_db": 14, 'timezone': 'Asia/Shanghai',
'CELERY_ENABLE_UTC': False})@app.task(name="funcname")
def async_funcname():
print("async function")
return Trueif __name__ == '__main__':
async_funcname.delay()这个文件名是app.py所以backend='app.RedisResult'，可以视项目环境具体设定，包括4.4.6版本也可以用这个方式兼容解决。
