Where can I see who is currently logged in to Plone?

Question

Is there a way to see who is currently logged in to a Plone site?

Rationale: I want to make sure not to interfer with users working on content when I restart the instance.

Answer 1

Out-of-the-box, there is no way to see if users are currently using your site, only if they have just been using it. Just tail the instance-Z2.log access logfile.

Note that due to the nature of the HTTP protocol, 'current' users of your site do not maintain a connection, and thus, until they are back again for the next request, there is no accurate way to determine if anyone is using the site.

There are work-arounds, such as using sessions and timeouts, that use recency to estimate how many users are still around. collective.portlet.usertrack is one such approach. Note that such approaches can have a hefty scalability penalty though.

If all you want to do is not inconvenience users during a restart, use a caching frontend and / or a load balancer and more than one instance instead. That way users see cached content or content generated by an instance still up while you restart your first instance.