[RFE] allow running in chroot-like environment

[malt3]

One pattern I am trying to accomplish is as follows:

• use distributions bootstrapping mechanism
  • debootstrap
  • dnf --installroot
  • apk --root
• try to get hashes from generated sysroot

As a workaround, I am copying repro-get into the generated sysroot and run systemd-nspawn as an easier chroot alternative to then run repro-get hash generate.
I believe having support for alternative sysroots in repro-get would simplify this process significantly!

[AkihiroSuda]

This may work for you?

repro-get --distro=debian --cache=/tmp/cache download SHA256SUMS-amd64 
repro-get --cache=/tmp/cache cache export .

YOUR-CHROOT-TOOL *.dpkg

[kpcyrd]

I think you'd probably want repro-get to do the bootstrapping, if you use debootstrap or pacstrap you possibly need to do complicated downgrades that might break in the future.

[malt3]

Let me clarify what I am trying to achieve here:

This is supposed to be a method to update a SHA256SUM file (check with upstream repositories for new versions of packages).
In order to do so I

• bootstrap a system using one of the aforementioned package managers and a list of packages without explicit versions (without repro-get and without a SHA256SUMS file).
• collect hashes of all installed packages in the generated sysroot

I would then like to manually review the generated hashes / updated versions so I have a kind of dependency lock file that I can store in git.