With Blubber v0.19.0 the COPY ./ . step changes the ownership of the parent directory. This was a bug that was fixed in newer versions.
Our app is based out of the directory /srv/app. /srv was owned by the flink user with the older version of Blubber, but owned by root in newer versions. Unfortunately, it seems like we inadvertently check for write permissions of the parent directory while resolving configuration.
This fails the tests, and would probably break production as well.
Additionally, system python in newer versions of debian does not allow pip to install into system python env. A virtualenv is required. The latest version of blubber's python builder now uses a virtualenv in /opt/lib/venv to account for this.
Our Flink production image is installed into system python. mediawiki-event-enrichment is expecting that pyflink is provided in the same python environment it is installed in. This is no longer the case if we use latest blubber.
In order to upgrade to later python and debian versions, we need to either