每次部署网站时，如何让Google App Engine清除内存缓存？ [英] How can I have Google App Engine clear memcache every time a site is deployed?

问题描述

标题要求全部。我正在建设的网站上的内容根本不会很快改变，所以Memcache可能会将数据存储几个月，除非我进行了更新。有没有办法在每次部署网站时清除缓存？我正在使用Python运行时。

更新1

使用 jldupont 的 answer 我将以下代码放在我的主请求处理脚本中...

更新2

我已经切换到 Koen Bok 在所选答案的评论中，并将所有我的memcache密钥与 os.environ ['CURRENT_VERSION_ID'] / 答案的第二次更新。这个解决方案似乎比我之前发布的功能更加优雅。

解决方案

你尝试过 flush_all （）函数？ 此处的文档。你需要一点逻辑和状态检测新的部署或具有执行冲洗的特殊脚本。

更新：查看您的一个脚本的绝对路径：每个部署都会发生变化。您可以使用 http://shell.appspot.com/ 来实验：

  import sys 
 sys.path 
  

['/ base / python_dist / lib / python25.zip'，
'/base/python_lib/versions/third_party/django-0.96'，
' base / python_dist / lib / python2.5 /'，
'/base/python_dist/lib/python2.5/plat-linux2'，
'/base/python_dist/lib/python2.5/lib -tk'，
'/base/python_dist/lib/python2.5/lib-dynload'，
'/ base / python_lib / versions / 1'，
'/ base / data / home / apps / shell / 1.335852500710379686 /']

查看与 /shell/1.335852500710379686 /

所以，只需保留这个部署状态变量的快照（在memcache ;-)中，并进行比较，以便进行刷新操作。

已更新2 ：由@Koen Bok建议，环境变量 CURRENT也可以使用_VERSION_ID （脚本文件的绝对路径的一部分）。

  import os 
 os.environ [CURRENT_VERSION_ID] 
  

The title asks it all. The content on the site I'm building wont change very quickly at all and so Memcache could potentially store data for months except for when I put up an update. Is there a way to make it clear the cache every time I deploy the site? I'm using the Python runtime.

Update 1

Using jldupont's answer I put the following code in my main request handling script...

Update 2

I've switched to the method mentioned by Koen Bok in the selected answer's comments and prefixed all my memcache keys with os.environ['CURRENT_VERSION_ID']/ with the helpful code in the answer's 2nd update. This solution seems to be much more elegant than the function I posted before.

解决方案

Have you tried flush_all() function? Docs here. You'll need a bit of logic & state to detect a new deployment or have a special script to perform the flushing.

Updated: look at the absolute path of one of your script: this changes on every deployment. You can use http://shell.appspot.com/ to experiment:

  import sys
  sys.path

['/base/python_dist/lib/python25.zip', '/base/python_lib/versions/third_party/django-0.96', '/base/python_dist/lib/python2.5/', '/base/python_dist/lib/python2.5/plat-linux2', '/base/python_dist/lib/python2.5/lib-tk', '/base/python_dist/lib/python2.5/lib-dynload', '/base/python_lib/versions/1', '/base/data/home/apps/shell/1.335852500710379686/']

Look at the line with /shell/1.335852500710379686/.

So, just keep a snapshot (in memcache ;-) of this deployment state variable and compare in order to effect a flushing action.

Updated 2: as suggested by @Koen Bok, the environment variable CURRENT_VERSION_ID can be used also (part of the absolute path to script files also).

 import os
 os.environ["CURRENT_VERSION_ID"]

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