Static nix-shell shebangs

[timokau]

I want to use nix-shell shebangs in my personal script collection to make sure all the needed dependencies are available. That has two disadvantages however:

• it adds significant overhead (~half a second on my machine if all dependencies are already present)
• dependencies may be garbage collected so usage of scripts may need internet access

So what I'd actually like is nix-shell like dependency declaration that is resolved statically whenever I update my channels. I've hacked together a proof of concept to do this in home-manager: I iterate through all my scripts, parse the nix-shell shebang line and generate a wrapper script that sets PATH. It is very hacky at the moment and I'm not sure yet if I will improve it in the future, but I thought it couldn't hurt to share it here. What do you think about including something similar as a home-manager library function?

Here is my POC which I import in my home.nix.

[wiedzmin]

This is my solution for python: https://github.com/wiedzmin/nixos-config/blob/master/modules/util.nix#L9. Will look into your PoC, looks interesting.

[stale]

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[timokau]

This is just a proof of concept and not very actionable at this point. It would need quite a bit of polishing before it could be included in home-manager. I'll close this for now. Please leave a message if you are interested in this issue and think that it should be re-opened.

[timokau]

I noticed that there are a few reactions to this issue. That may be a reason to leave it open. I do not plan to work on this though, at least not in the near future. The stale bot was probably added to cut down on the backlog, so I'll leave this closed unless somebody wants to push it forward. I'd be happy if somebody else comes up with a solution that can be integrated into home-manager.

[rycee]

Yeah, I think it is a good idea. But I would suggest creating a separate tool that provides this feature, then we can use it here. It would then also be useful for people not using Home Manager.

[timokau]

I agree, it would be very nice to have this as an external tool. It's currently hard to integrate such a tool into the home-manager and nixos profile generation though. The scripts should be wrapped/patched at "home-manager build" time and then be placed in the profile. The way forward would probably be a library that you could import into your nixos and home-manager configuration. As I said, I don't have any plans to work in this though.