niv VS nixery

Sometimes, nixpkgs does not have the Haskell package version I need. In this case, I override the package with a custom one in the Haskell package set. I use niv to pin the version of the package I want to use. If I want to add it from GitHub, that is easy:

niv

Flakes work. An alternative is niv which was once popular and provides a good developer experience.

Essentially you can just think of it as a standardized default.nix/shell.nix with built-in Niv integration.

I agree that the FP part is not the only issue. It's that the community feels a bit more academic/I'll fix this for myself in the way that works best for me.

You can indeed achieve some reproducibility with Docker. It's tricky though, as you'd have to pin exact package versions of software. If you'd `FROM ubuntu:$VERION`, and would run an `apt-get update`, you're not guaranteed to get the same software.

Nix is like ZFS, as that it breaks the wall between two previously distinct area's. Those being building software, and installing/configuration software on your OS. It's quite different from the snapshot-everything methodology that Docker uses. Yeah, one can split in multi-stage images etc, but than you'll be keeping track of which dependencies need to be moved between the stages yourself, in a manner that cannot be abstracted away, so you're doomed to repeat the same patterns over and over again.

People also state that LVM + ext3 is more than sufficient compared to the complexity of ZFS. They miss out on the fact on how much more fine grained solutions are possible with ZFS.

I've used niv [0] before flakes arrived, and am actually still using that instead of flakes. The experimental nature of them has scared me away from them, as I'm not daily involved in this ecosystem at the moment.

[0] https://github.com/nmattia/niv#niv

You can use something like Niv to manage additional sources. I use it to fetch some Emacs packages, for example ligature.el. Then you update the package using $ niv update.

One thing that made this easier was switching from using Nix channels to explicitly pinning my dependencies with Niv. I honestly never fully understood how channels worked, and it's just much nicer to have everything specified in my Git repo. The exact commit of Nixpkgs that I'm using is in my sources.json file, so "reverting" just means checking out an older commit of my configs from Git then running nixos-rebuild switch. If I were redoing my dotfiles today I'd probably use Nix Flakes rather than Niv, but I suspect that Niv is still an easier option to get started with.

Does someone know of a way to remove unused pinned packages via [niv](https://github.com/nmattia/niv)?

Pin nixpkgs, and version control it. If you're using flakes, then just version control the flake.lock alongside your configuration. If you're not using flakes, you can use niv to easily pin nipxkgs, at the expense of some boiler plate.

The ones from https://nixery.dev/

You can build your own with https://nixery.dev/

I built a service for doing this ad-hoc via image names a few years ago and it enjoys some popularity with CI & debugging use-cases: https://nixery.dev/

name is eerily similar to `nixpkgs`, i.e. the monorepo that defines all packages and one of the underlying technologies here. i get the play on buildpacks, but still, as a nix user it makes me do a double take reading the name

this is neat though, and in political terms, the elevator pitch mentions nix itself as an implementation detail in passing. hopefully, if this catches on, it'll function as a non-threatening gateway drug to nix itself, when users inevitably go digging into the weeds

for anyone interested, prior art on the nix container front: https://nixery.dev

Wow, this is excellent! At a previous job, we had been using k8s + knative to spin up containers on demand, and likewise were unhappy with the delays. Spawner seems excellent.

One question: have you had to do any custom container builds on demand, and if so, have you had to deal with large containers (e.g. a Python base image with a few larger packages installed from PyPI)? We would run up against extremely long build image times using tools like kaniko, and caching would typically have only a limited benefit.

I was experimenting using Nix to maybe solve some of these problems, but never got far enough to run a speed test, and then left the job before finishing. But it seems to me some sort of algorithm like Nixery uses (https://nixery.dev) to generate cacheable layers with completely repeatable builds and nothing extraneous would help.

Maybe that's not a problem you had to solve, but if it is, I'd love your thoughts.

Nixery – Docker images on the fly with Nix\ (38 comments)