eea.cache 6.3

Introduction

This package combines the features from lovely.memcached and plone.memoize.ram. It provides a decorator and utility for Memcaches at EEA. The decorator allows you set dependencies known by eea.cache

Contents

Installation

zc.buildout

If you are using zc.buildout and the plone.recipe.zope2instance recipe to manage your project, you can do this:

• Update your buildout.cfg file:

  • Add eea.cache to the list of eggs to install

  • Tell the plone.recipe.zope2instance recipe to install a ZCML slug

  • Add memcache

  parts +=
    libevent
    memcached
    memcached-ctl
  
  effective-user = zope-www
  
  [instance]
  ...
  eggs =
    ...
    eea.cache
  
  zcml =
    ...
    eea.cache-overrides
  
  
  [libevent]
  recipe = zc.recipe.cmmi
  url = http://www.monkey.org/~provos/libevent-1.4.8-stable.tar.gz
  
  [memcached]
  recipe = zc.recipe.cmmi
  url = http://www.danga.com/memcached/dist/memcached-1.2.6.tar.gz
  extra_options = --with-libevent=${libevent:location}
  
  [memcached-ctl]
  recipe = lovely.recipe:mkfile
  path = ${buildout:bin-directory}/memcached
  mode = 0755
  content =
   #!/bin/sh
   export LD_LIBRARY_PATH=${libevent:location}/lib
  
   PIDFILE=${memcached:location}/memcached.pid
      case "$1" in
        start)
         ${memcached:location}/bin/memcached -d -u ${buildout:effective-user} -P $PIDFILE
          ;;
        stop)
          kill `cat $PIDFILE`
          ;;
        restart|force-reload)
          $0 stop
          sleep 1
          $0 start
          ;;
        *)
          echo "Usage: $SCRIPTNAME {start|stop|restart}" >&2
          exit 1
          ;;
      esac

• Re-run buildout, e.g. with:

  $ bin/buildout -c buildout.cfg

• Restart memcache and Zope:

  $ bin/memcached restart
  $ bin/instance restart

Dependencies

EEA Cache has the following dependencies:

• Plone 4+

Source code

Latest source code (Zope 2 compatible):

• Plone Collective on Github

• EEA on Github

Cache decorator

>>> def key(method, self):
...     return method.__name__

>>> from eea.cache import cache
>>> @cache(key, dependencies=["frontpage"])
... def myMethod(num):
...     return num*num

Lets clear any running memcache

>>> from eea.cache.event import InvalidateCacheEvent
>>> from zope.event import notify
>>> notify(InvalidateCacheEvent(raw=True, dependencies=['frontpage']))

Our myMethod will now be cached with the key returned from the method ‘key’ and with dependency ‘frontpage’.

>>> myMethod(2)
4
>>> myMethod(3)
4

>>> notify(InvalidateCacheEvent(raw=True, dependencies=['frontpage']))
>>> myMethod(3)
4

Cache lifetime

By default your content is cached in memcache for one hour (3600 seconds). You can change this by adding an int property within: ZMI > portal_properties > site_properties called memcached_defaultLifetime and set it’s value to 86400 (one day) for example.

ex: in order to cache the result only for 4 minutes
>>> @cache(key, dependencies=["frontpage"], lifetime=240)
... def myMethod(num):
...     return num*num

Copyright and license

The Initial Owner of the Original Code is European Environment Agency (EEA). All Rights Reserved.

The eea.cache (the Original Code) is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

More details under docs/License.txt

Funding and project management

EEA - European Environment Agency (EU)

Changelog