In order to support a progressive rollout of new PHP versions, we need to produce different MediaWiki images for each PHP version.
Our container image build scripts in the release project should support the PHP version as a build argument.
There are two parts to achieving this goal and putting it to use:
- scap gains the ability to build multiple "flavours" for each image "kind" (mw, web), where the configuration that defines a given flavor at least provides the ability to set the base production image used (e.g., by way of build arguments).
- scap gains the ability to map an arbitrary number of mw-on-k8s helmfile releases within a given k8s namespace to the image flavours they should use, and this information is published for consumption by helmfile via values files in /etc/helmfile-defaults/mediawiki/release.
See also T370934#10104089 for more detailed discussion on some of these topics.