This package provides a memcached cache backend for Django using pylibmc. You want to use pylibmc because it's fast.
Django has direct support for pylibmc. To use it, set you cache backend:
CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.memcached.PyLibMCCache', 'LOCATION': '127.0.0.1.11211', } }
See the Django documentation for details about using this cache backend.
Two reasons to use django-pylibmc instead are:
- You need to use the binary protocol
- You need to use a username and password to access the memcached server (such as with Memcachier on Heroku).
django-pylibmc requires pylibmc 1.4.1 or above. It supports Django 1.7 through 1.9, and Python versions 2.7, 3.4, and 3.5.
Get it from pypi:
pip install django-pylibmc
or github:
pip install -e git://github.com/django-pylibmc/django-pylibmc.git#egg=django-pylibmc
Your cache backend should look something like this:
CACHES = { 'default': { 'BACKEND': 'django_pylibmc.memcached.PyLibMCCache', 'LOCATION': 'localhost:11211', 'TIMEOUT': 500, 'BINARY': True, 'OPTIONS': { # Maps to pylibmc "behaviors" 'tcp_nodelay': True, 'ketama': True } } }
To use a memcached local socket connection,
set LOCATION
to the path to the file, i.e. '/var/run/memcached/memcached.sock'
.
If you want to use the memcached binary protocol, set the BINARY
key's
value to True
as shown above. BINARY
is False
by default.
If you want to control pylibmc behaviors, use the
OPTIONS
. OPTIONS
is an empty dict by default.
Pylibmc supports compression and the
minimum size (in bytes) of values to compress can be set via the Django
setting PYLIBMC_MIN_COMPRESS_LEN
. The default is 0
, which is disabled.
Pylibmc 1.3.0 and above allows to configure compression level, which can
be set via the Django setting PYLIBMC_COMPRESS_LEVEL
. It accepts the
same values as the Python zlib
module. Please note that pylibmc changed the default from 1
(Z_BEST_SPEED
)
to -1
(Z_DEFAULT_COMPRESSION
) in 1.3.0.
Optionally, the memcached connection can be configured with environment variables (on platforms like Heroku). To do so, declare the following variables:
MEMCACHE_SERVERS
MEMCACHE_USERNAME
MEMCACHE_PASSWORD
When setting a cache value, memcache allows you to set an expiration for the value. Commonly, the value is set to a timeout in seconds. However, other values are allowed including Unix timestamps and 0 for "never expire". The highest number of seconds is 30 days - more than that, and the value is treated like a timestamp.
Django instead tries to work with cache timeouts in seconds after the current time. 0 is treated as 0 seconds, meaning the item should expire immediately. A timeout of None signals that the item should not expire. There is some support for memcache-style Unix timestamps as well.
In the distant past (Django 1.3?), a timeout of 0 was converted to the default timeout.
The current django-pylibmc behaviour is to pass 0 to the backend, which should be interpreted as "never expire". Omiting the timeout will get the Django default.
In the future, django-pylibmc will adopt the latest Django behaviour. The safest solution for your own code is to omit the timeout parameter (and get the default timeout), or set it to a timeout in seconds (less than 30 days). This way, your code will work when the Django behaviour is adopted. Avoid using a timeout of 0, None, or a negative number.
Install tox:
pip install tox
Run the tests like this:
tox