Add support for variables in /etc/apk/repositories like Yum has
This would IMO solve #10756 by replacing the repo in /etc/apk/repositories by a caching proxy
An example need of such a feature is documented in the wiki: https://wiki.alpinelinux.org/wiki/Alpine_newbie_apk_packages#New_users:_installing_needed_packages
# old /etc/apk/repositories from the example above
cat > /etc/apk/repositories << EOF; $(echo)
http://dl-cdn.alpinelinux.org/alpine/v$(cat /etc/alpine-release | cut -d'.' -f1,2)/main
EOF
would become:
# proposed /etc/apk/repositories
cat > /etc/apk/repositories << EOF; $(echo)
http://dl-cdn.alpinelinux.org/alpine/v\$releasever/main
EOF
Now that is of little use, BUT we use Artifactory as cache and thus point our Alpine containers to a repo mirror there... but need a separate repo file for every alpine release or synthesize a repo file based on the alpine release... that sounds easy enough but the code that needs to synthesize the repo file needs to be running outside the container and thus has to guess the correct release number from docker tags for various base images (node, go, java, ...)...
We would love to be able to just bind mount /etc/apk/repositories
with our artifactory repositories (and credentials) without fancy magic and use $releasever
as a placeholder for the version inside them.