I have a race condition in Celery
. Inspired by this – http://ask.github.io/celery/cookbook/tasks.html#ensuring-a-task-is-only-executed-one-at-a-time I decided to use memcache to add locks to my tasks.
These are the changes I made:
python-memcached
# settings for memcache
CACHES = {
'default': {
'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
'LOCATION': '127.0.0.1:11211',
}
}
After this I login to my shell and do the following
>>> import os
>>> import django
>>> from django.core.cache import cache
>>> os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'proj.settings.base')
>>> cache
<django.core.cache.DefaultCacheProxy object at 0x101e4c860>
>>> cache.set('my_key', 'hello, world!', 30) #display nothing. No T/F
>>> cache.get('my_key') #Display nothing.
>>> from django.core.cache import caches
>>> caches['default']
<django.core.cache.backends.memcached.MemcachedCache object at 0x1048a5208>
>>> caches['default'].set('my_key', 'hello, world!', 30) #display nothing. No T/F
>>> caches['default'].get('my_key') #Display nothing.
also did pip install python-memcached
Using Python 3.6
, Django==1.10.5
What am I doing wrong? Any help will be appreciated.
2
Answers
The problem was, memcached was killed for some reason and I was assumed it was still running. My bad. Now it works all perfectly.
For anyone who is stuck on a similar problem you want to make sure you are still running memcached, try
memcached -vv
Keeping this here for reference.
If your install is looking like mine is starting to look (in which case, you have my sympathies; for RHEL is one platform where django seems thinner on-the-ground than this-week’s python):
then checking the status on memcache is as easy with the same commands we’ve been using for 20 years:
There are other commands one can use on RHEL/EL7 (#fridgeArt), but I prefer compatible workflows in spite of resume-driven differentiation. >:-(
Here’s how to launch it with -vv under EL and debuntus too: https://stackoverflow.com/a/22239764/2066657