Hi:
I just installed this module and I love it.

I am running Pressflow 6.20 with cacheing in "normal" mode and the module seems to be working perfectly. I am interested in setting Pressflow into "external cache" mode and using it with Varnish.

Pressflow says Elysia Cron is "potentially incompatible with external cache mode". This would be related to " The aggressive/external cache mode causes Pressflow to skip the loading (boot) and unloading (exit) of enabled modules when serving a cached page."

However this does not necessarily mean the module will not work. I was wondering if you have any insight about whether I can conctinue using this module with external caching, and/or if there are any settings I should use.

FYI, I am pinging Cron using the Acquia cron service, which calls www.example.com/cron.php every 5 minutes. None of my crons need to run much faster than that. So that seems to work. But perhaps caching will get in the way of this?

Thanks for any insights.

Comments

jrstmartin’s picture

jrstmartin commented

I think you just have to make sure the following statement is included in /etc/varnish/default.vcl within subroutine "sub vcl_recv":

// No varnish for install, update.php or cron.php.
if (req.url ~ "install\.php|update\.php|cron\.php") {
  return (pass);      
}

This will tell Varnish to always fetch a request to cron.php, among others, from the backend and not the cache. Even though the URL is slightly different for Elysia Cron compared to normal cron (http://site.com/sites/all/modules/elysia_cron/cron.php?cron_key=my_key), that REGEX should still match it.

If you use project Mercury, this is already done for you. Fourkitchens wiki has an example default.vcl with this included too.

gotheric’s picture

gotheric commented

I don't know how pressflow works in "external cache" mode, sorry.

If it skips the boot of the module this could be potentially bad in D5 and D6 with normal cron execution (= without replacing cron.php command), and should give no problems on D7.
If you replace cron.php call the boot phase is not used, so it should work well.
No problems about the exit phase.

However a cron call should NEVER be cached (it makes no sense), so i think pressflow should manage this by not caching any cron calls...

About varnish: follow the instructions of jrstmartin. Like stated before, cron calls should not be cached, so you must configure varnish to skip that calls.

gotheric’s picture

gotheric commented
Status: Active » Fixed
gotheric’s picture

gotheric commented
Status: Fixed » Closed (fixed)