How to replace rocker templating?

[bendikro]

I'm sad to see that the project is discontinued :-(

From the README:

Now, most of the critical and outstanding features of rocker can be easily covered by docker build or other well-supported tools.

Could you please give some advice on how to replace rocker's template support with standard Docker?
We have many images that heavily rely on templating to support inheritance and various versions of OSes and tools, which was the main reason we used rocker. Docker simply had way too many unnecessary restrictions. Has this changed lately?

A typical image starts with:
{{ define "parentImageTpl"}}{{ .parentImageNamePrefix }}utils:{{ .distroName }}{{ .distroVersion }}{{end}} FROM {{template "parentImageTpl" .}}

Also, how to support MOUNT during build with standard docker?
E.g.
# yum cache using rocker mount {{ if (ne .packageCache "") }} MOUNT {{ .packageCache }}/yum:/var/cache/yum {{end}}

Any advice would be appreciated!

[ybogdanov]

Hey, @bendikro, thanks for your question.

I commented on a similar question here #199 (comment), hope it helps a bit.

Regarding your particular cases:

1. Try to pre-process your Dockerfile before doing docker build
2. Consider a local caching proxy; maybe there is something yum-specific