Is it possible for a plugin to add to the UI in the sidebar? (i.e. above/below Build Queue & Build Executor Status)

[Andrew Taylor]

Hi,

I have been unable to find much information on making general Jenkins UI contributions through a plugin, other than in a few select places - is it possible to add a another box similar to the Build Queue and Build Executor Status boxes in the main UI?

I would like to add additional information, such as the usage/capacity of my OpenStack cloud - which is directly relevant to the number of slave machines available, and an indication as to the reasons for the current size of the queue, hence the sidebar is the logical place to put it.
I notice that the "Wasted Minutes" plugin from Cloudbees does add something there, but although it's free, it's not open source, so I can't see their code.

Has anyone got any ideas/samples?

Many thanks,
-Andy