On 2014-02-20 2:50 PM, Bartosz Dziewoński wrote:
On Thu, 20 Feb 2014 23:21:37 +0100, Greg Grossmeier greg@wikimedia.org wrote:
<quote name="Bartosz Dz." date="2014-02-20" time="22:32:42 +0100"> > It's worth noting that WMF branches also include temporary hacks to > keep current JS/CSS and cached HTML output compatible (for at least 30 > days), while release branches never contain them (and thus require > HTML caches to be purged during the upgrade process).
Isn't that:
Feel free to base it off of either. There shouldn't be any WMF-specific things in those wmfXX branches. If there is, it is a commit called something like "Commit of various WMF live hacks". That one commit can be safely reverted.
eg: https://git.wikimedia.org/commit/mediawiki%2Fcore.git/a868d086b68f05e7f93727...
Nope, I mean different hacks (that people generally don't bother ops/deployers with), like the ones being removed by https://gerrit.wikimedia.org/r/#/c/61075/ or https://gerrit.wikimedia.org/r/#/c/72151/ or https://gerrit.wikimedia.org/r/#/c/102492/ or https://gerrit.wikimedia.org/r/#/c/82102/ . They are required because (to simplify) generated page HTML (which is cached for up to 30 days on our cluster) includes links to "autoupdating" JS and CSS code. Thus any JS/CSS changes need to be compatible with older generated HTML.
I've thought for awhile that there are better ways to deal with the cache than this. My thought was a sort of snapshot feature for ResourceLoader: https://www.mediawiki.org/wiki/User:Dantman/Code_Ideas#rl-snapshot
- We start outputting &version= on the load.php requests for skin resources. - WMF runs a script that dumps the current state of just about all modules into a snapshot folder. - The MediaWiki upgrade is performed. - Some configuration makes reference to the location of the snapshot. - When load.php sees an old &version= it serves resources from the snapshot instead of MediaWiki, this way even if the styles, scripts, etc... have been modified, the module has been renamed, or even entirely deleted the module is still served to old pages.
This way we don't have to create or revert any hacks at all, we are unrestricted in the types of CSS/JS and HTML changes we make, and WMF doesn't get any special treatment since now any wiki large enough to have issues resetting its entire cache can take advantage of it.
~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://danielfriesen.name/]