[REQ] Allow content from llb source to satisfy package deps

[cpuguy83]

What kind of request is this?

New feature

What is your request or suggestion?

Sometimes content just isn't in a package repo or the one in the repo is too old, too new, missing patches, whatever.
It would be cool to allow injecting content (e.g. from a docker image) into a build that satisfies the package dependency.
The package should still be declared a dependency but dalec can fetch the content and wrap it up in a (binary) package itself.

This would be especially useful for build-time deps.
I'm not sure if we should support this for runtime deps, but I'm not completely against it.

At build time we can have some optimizations so we don't need to do a copy we can just mount the content in and create a stub package to satisfy the package manager.

An example use for this would be msft-go where we don't have packages for this except for azlinux, but we still need to build on ubuntu for certain cases.
With this proposed feature we could pull in the signed binaries (or just use the docker image) to satisfy the go requirement.

Are you willing to submit PRs to contribute to this feature request?

• Yes, I am willing to implement it.