[xwiki-devs] [Vote] Move the caches files to permdir and make the launch of XWiki faster

Hi. Currently, XWiki is quite long to start, and this is mainly because of the LESS compiler which generates the CSS file of the skin. Fortunately, we cache the results of the compilation in the LESS cache, which is stored in the file-system (this is important). Some actions can be done to make the launch quicker: 1 - Not purge the cache at startup. The idea is to keep the cache of the previous launch of XWiki, so LESS would have nothing to compile anymore. This does not solve the first launch issue, but it is a great progress anyway. The disadvantage of this is that restarting XWiki will not solve any issue related to a bad cached file (ex: a buggy CSS file stored in the cache will still be there after a restart. The only way to fix this is to re-save the buggy LESS resource). Note that this behaviour can easily be changed by modifying a config file: http://extensions.xwiki.org/xwiki/bin/view/Extension/LESS+Module#HCacheStra… 2 - During the build of XE, run an integration test that performs a simple view request to XWiki in order to make the LESS compiler builds the CSS file and pushes it into the cache. After the integration test, we just copy the generated LESS cache file into the Jetty/HSQLDB distribution, and so when you launch XWiki from this distribution, you use the pre-generated cache. Of course it could only work for our Jetty distributions that users test locally. It will not solve the issue on production servers. But it is already good that a user have a good impression by starting XWiki quickly on her computer. I have made a proof of concept on a branch [1] and the thing is working well. The first request to XWiki is really faster. The only blocking point I have now is that the current cache directory is currently configured to be the temporary directory. Instead, I need to use a directory from the distribution (where I can put my pre-generated cache files). I have solved this locally by setting an absolute path to my "data" folder [2], but it is not clean. Thomas suggested me to configure all the caches to use the "permdir" directory, which actually is the "data" directory in the case of our jetty distributions, and so it does the job. So the vote is for the following proposal: 1 - move the cache files to permdir 2 - do not purge the LESS cache at startup (by default) 3 - add a new module that pre-generate the LESS cache file to make the first XWiki launch faster Here is my +1. Thanks, [1] https://github.com/xwiki/xwiki-enterprise/compare/feature-datalesscache [2] http://jira.xwiki.org/browse/XWIKI-10879?focusedCommentId=85369&page=co… -- Guillaume Delhumeau (gdelhumeau(a)xwiki.com) Research & Development Engineer at XWiki SAS Committer on the XWiki.org project