我有一些使用 Celery 线程的非常简单的周期代码;它只是打印“Pre”和“Post”并在中间休眠。它改编自这个 StackOverflow 问题 and 这个链接网站
from celery.task import task
from celery.task import periodic_task
from django.core.cache import cache
from time import sleep
import main
import cutout_score
from threading import Lock
import socket
from datetime import timedelta
from celery.decorators import task, periodic_task
def single_instance_task(timeout):
def task_exc(func):
def wrapper(*args, **kwargs):
lock_id = "celery-single-instance-" + func.__name__
acquire_lock = lambda: cache.add(lock_id, "true", timeout)
release_lock = lambda: cache.delete(lock_id)
if acquire_lock():
try:
func()
finally:
release_lock()
return wrapper
return task_exc
LOCK_EXPIRE = 60 * 5 # Lock expires in 5 minutes
@periodic_task(run_every = timedelta(seconds=2))
def test():
lock_id = "lock"
# cache.add fails if if the key already exists
acquire_lock = lambda: cache.add(lock_id, "true", LOCK_EXPIRE)
# memcache delete is very slow, but we have to use it to take
# advantage of using add() for atomic locking
release_lock = lambda: cache.delete(lock_id)
if acquire_lock():
try:
print 'pre'
sleep(20)
print 'post'
finally:
release_lock()
return
print 'already in use...'
这段代码never prints 'already in use...'
;当我使用时也会出现同样的现象@single_instance_task
装饰师。
你知道出了什么问题吗?
编辑:我简化了问题,以便它不会写入内存(使用全局或 django 缓存);我还是没见过'already in use...'
编辑:当我将以下代码添加到我的 Django settings.py 文件中时(通过将代码更改为https://docs.djangoproject.com/en/dev/topics/cache/一切都按希望进行,但仅当我使用端口 11211 时(奇怪的是,我的服务器位于端口 8000)
CACHES = {
'default': {
'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
'LOCATION': [
'127.0.0.1:11211'
]
}
}