On Thu, Jan 18, 2018 at 9:57 PM, Adam Baso <abaso@wikimedia.org> wrote:

Adding to this, one thing to consider is DNT - is there a way to invoke EL so that such traffic is appropriately imputed or something?

The EventLogging client respects DNT [0]. When the user enables DNT, mw.eventLog.logEvent is a NOP.

I don't see any mention of DNT in the Varnish VCLs around the the /beacon endpoint or otherwise but it may be handled elsewhere. While it's unlikely, there's nothing stopping a client sending a well-formatted request to the /beacon/event endpoint directly [1], ignoring the user's choice.

-Sam

[0] https://phabricator.wikimedia.org/diffusion/EEVL/browse/master/modules/ext.eventLogging.core.js;4480f7e27140fcb8ae915c1755223fd7a5bab9b9$251

[1] https://phabricator.wikimedia.org/diffusion/EEVL/browse/master/modules/ext.eventLogging.core.js;4480f7e27140fcb8ae915c1755223fd7a5bab9b9$215