Moved over from bug 43448:
Could we have some sort of monitoring of if HTCP packets cause
things actually get purged. squid/varnish purging suddenly not working seems to
have happened quite a few times in the past (all for different reasons), and we
have no monitoring of it, (We don't even have any unit tests on the MW side for
it as far as I am aware).
This is bad since:
*Most people don't have squid/varnish set up in their dev environment, so
people don't notice on local test wikis.
*The symptoms are gradual, and usually pass unnoticed for some time
*With exception of images, the people primarily effected are anons, who are
less likely to know how to report the issue.