eea.cache 7.1

Tools and config for memcache related caching

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

Note

This add-on doesn’t do anything by itself. It needs to be integrated by a developer within your own products. For reference you can check the eea.app.visualization package.

Contents

Contents

• Introduction

• Contents

• Main features

• Install

• Dependencies

• Source code

• Cache decorator

• Cache lifetime

  • Cache lifetime override per key

• Invalidate cache

  • memcache.invalidate

  • varnish.invalidate

  • cache.invalidate

• Copyright and license

• Funding and project management

• Changelog

  • 7.1 - (2014-10-01)

  • 7.0 - (2014-08-27)

  • 6.3 - (2014-01-21)

  • 6.2 - (2013-10-04)

  • 6.1 - (2013-06-17)

  • 6.0 - (2013-05-20)

  • 5.1 - (2013-02-04)

  • 5.0 - (2012-10-08)

  • 4.3 - (2012-07-13)

  • 4.2 - (2012-02-06)

  • 4.0 - (2011-11-07)

  • 0.3 - (2010-11-22)

  • 0.2 - (2010-11-10)

  • 0.1 - (2009-11-10)

Main features

1. Extends and overrides plone.memoize cache adapters to work with memcache

2. Provides an extended @cache decorator that supports:

   • cache lifetime override per method

   • dependencies string in order to bulk invalidate cache

   • auto-invalidation of cache when ObjectModifiedEvent is triggered

3. Possibility to manually invalidate cache via URL.

Install

• Add eea.cache to your eggs and zcml section in your buildout and re-run buildout:

  eggs =
    ...
    eea.cache
  
  zcml =
    ...
    eea.cache
    eea.cache-overrides

• You can download a sample buildout from https://github.com/eea/eea.cache/tree/master/buildouts/plone4

• Install eea.cache within Site Setup > Add-ons

• Start memcache:

  $ bin/memcached start

Dependencies

• python-memcached

• plone.memoize

• plone.uuid

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)
9

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.

Cache lifetime override per key

Starting with eea.cache 5.1 you can also pass a lifetime key with the duration in seconds which will override the defaultLifetime either given from the portal property or the default one from lovely.memcached of 3600 seconds:

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

Invalidate cache

If you use cache decorator for BrowserView methods or directly on Zope objects methods cache will be automatically invalidated when object is modified (ObjectModifiedEvent is triggered):

>>> from Products.Five.browser import BrowserView

>>> class XXX(BrowserView):
...     @cache(key)
...     def title(self):
...         return self.context.title_or_id()

You can disable auto invalidation by providing the auto_invalidate param to @cache decorator:

>>> @cache(key, auto_invalidate=False)
... def title(self):
...     return self.context.title_or_id()

memcache.invalidate

In order to manually invalidate memcached cache per object this package provides a browser view called memcache.invalidate. It will invalidate all memcached methods associated with current object’s UID:

http://localhost:2020/Plone/front-page/memcache.invalidate

You can also manually invalidate related items and back references:

http://localhost:2020/Plone/front-page/memcache.invalidate/relatedItems

http://localhost:2020/Plone/front-page/memcache.invalidate/backRefs

By default this method can be called by users with these roles:

• Editor

• CommonEditor

• Owner

• Manager

varnish.invalidate

In order to manually invalidate memcached cache per object this package provides a browser view called varnish.invalidate. It will invalidate all memcached methods associated with current object’s UID:

http://localhost:2020/Plone/front-page/varnish.invalidate

You can also manually invalidate related items and back references:

http://localhost:2020/Plone/front-page/varnish.invalidate/relatedItems

http://localhost:2020/Plone/front-page/varnish.invalidate/backRefs

By default this method can be called by users with these roles:

• Editor

• CommonEditor

• Owner

• Manager

cache.invalidate

In order to manually invalidate cache (memcached and varnish) per object this package provides a browser view called cache.invalidate. It will call memcache.invalidate and varnish.invalidate:

http://localhost:2020/Plone/front-page/cache.invalidate

You can also manually invalidate related items and back references:

http://localhost:2020/Plone/front-page/cache.invalidate/relatedItems

http://localhost:2020/Plone/front-page/cache.invalidate/backRefs

By default this method can be called by users with these roles:

• Editor

• CommonEditor

• Owner

• Manager

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

7.1 - (2014-10-01)

• Feature: invalidate Memcache now appear on cache form as one of the options. [ghicaale refs #21143]

• Feature: created handler to invalidate only Varnish. [ghicaale refs #21143]

• Feature: improved result messages. [ghicaale refs #21143]

7.0 - (2014-08-27)

• Upgrade step: Within “Plone > Site setup > Add-ons” install EEA Cache [voineali refs #20678]

• Pre-upgrade step: Also add eea.cache within buildout zcml directive before eea.cache-overrides [voineali refs #20678]

• Feature: Added a browser view called cache.invalidate that allows editors to manually invalidate cache (including varnish and memcache). It also supports invalidation for related-items and back-references [voineali refs #20678]

• Feature: Added a browser view called memcache.invalidate that allows users to manually invalidate memcache. It also supports invalidation of relatedItems and back-references memcache [voineali refs #20678]

• Change: Auto-invalidate all cache associated with current object’s UID when ObjectModifiedEvent is triggered [voineali refs #20678]

6.3 - (2014-01-21)

• Bug fix: removed wrongly added blockquotes within README.rst [ichim-david refs #18064]

• Feature: adding Sphinx-generated documentation in Page Template format [batradav refs #9502]

6.2 - (2013-10-04)

• Change: updated zope imports with the versions that require minimum Plone 4.1 for eea.cache [ichimdav refs #15651]

6.1 - (2013-06-17)

• Cleanup: Use logger.debug instead of logger.info for debug messages [avoinea]

6.0 - (2013-05-20)

• Feature: Removed lovely.memcached dependency [voineali refs #14343]

5.1 - (2013-02-04)

• Feature: added information for contributors [ciobabog refs #13892]

• Feature: added ability to pass a lifetime key to the cache decorator in order to cache it for a determined period different from the default lifetime [ichimdav #13677]

• Upgrade step: (optional) Within ZMI > portal_properties > site_properties add an int property called memcached_defaultLifetime and set it’s value to 86400 (one day) or any value that fits your needs.

• Feature: Ability to set memcached default lifetime, which by now was hardcoded to one hour (3600 seconds) [voineali refs #13677]

5.0 - (2012-10-08)

• Change: Updated README and egg’s metadata [voineali refs #5434]

4.3 - (2012-07-13)

• Bug fix: fixed markup of HISTORY.txt file [ciobabog refs #5231]

4.2 - (2012-02-06)

• no changes

4.0 - (2011-11-07)

• Feature: Plone 4.x compatible release [ghicaale #4309]

0.3 - (2010-11-22)

• Bug fix: fixed tests namespace in order to be used within hudson [voineali #3821]

0.2 - (2010-11-10)

• Bug fix: added fake memcache client in order to fix broken doctests [voineali]

0.1 - (2009-11-10)

• Initial release