Hi Neels,

I've seen some discusion (unfortunately on the sysmocom internal jaberr room, not on a public osmocom channel) related to the docker based jenkins verification jobs as follows:

ADD http://download.opensuse.org/repositories/network:/osmocom:/nightly/Debian_8... /tmp/Release RUN apt-get update && apt-get install -y --no-install-recommends libosmocore-dev

The "ADD" line will check if the "Release" file of the repository has changed. If yes, the cache will be invalidated, and the following line[s] will be re-run. If no, then the cache will remain.

It's sub-optimal in that any change to the repository (even those that are unrelated to the packages used, [libosmocore-dev in this example]) will trigger an image re-build. But at least it will guarantee that any update to the libosmocore-dev package will trigger an image rebuild.

See http://git.osmocom.org/docker-playground/tree/osmo-stp-master/Dockerfile for a real-world example

Regards, Harald