How to use 2 different cache backends in Django?

Question

I need to use memcached and file based cache. I setup my cache in settings:

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.filebased.FileBasedCache',
        'LOCATION': 'c:/foo/bar',
    },
    'inmem': {
        'BACKEND': 'django.core.cache.backends.dummy.DummyCache',
    }
}

dummy is temporary. Docs says:

cache.set('my_key', 'hello, world!', 30)
cache.get('my_key')

OK, but how can I now set and get cache only for 'inmem' cache backend (in future memcached)? Documentation doesn't mention how to do that.

Answer 1

CACHES = {
  'default': {
    'BACKEND': 'django.core.cache.backends.filebased.FileBasedCache',
    'LOCATION': 'c:/foo/bar',
  },
  'inmem': {
    'BACKEND': 'django.core.cache.backends.dummy.DummyCache',
  }
} 

from django.core.cache import get_cache, cache
inmem_cache = get_cache('inmem')
default_cache = get_cache('default')
# default_cache == cache 

Answer 2

Since Django 1.9, get_cache is deprecated. Do the following to address keys from 'inmem' (addition to answer by Romans):

from django.core.cache import caches
caches['inmem'].get(key)

Answer 3

In addition to Romans's answer above... You can also conditionally import a cache by name, and use the default (or any other cache) if the requested doesn't exist.

from django.core.cache import cache as default_cache, get_cache
from django.core.cache.backends.base import InvalidCacheBackendError

try:
    cache = get_cache('foo-cache')
except InvalidCacheBackendError:
    cache = default_cache

cache.get('foo')

Answer 4

From the docs:

>>> from django.core.cache import caches
>>> cache1 = caches['myalias']
>>> cache2 = caches['myalias']
>>> cache1 is cache2
True

Answer 5

Create a utility function called get_cache. The get_cache method referenced in other answers doens't exists in the django.core.cache library in some django versions. Use the following insteaed

from django.utils.connection import ConnectionProxy
from django.core.cache import caches

def get_cache(alias):
  return ConnectionProxy(caches, alias)


cache = get_cache('infile')
value = cache.get(key)

Answer 6

Unfortunately, you can't change which cache alias is used for the low-level cache.set() and cache.get() methods.

These methods always use 'default' cache as per line 51 (in Django 1.3) of django.core.cache.__init__.py:

DEFAULT_CACHE_ALIAS = 'default'

So you need to set your 'default' cache to the cache you want to use for the low-level cache and then use the other aliases for things like site cache, page cache, and db cache routing. `