Add Nix flake for NixOS/nix-based builds

[vinylen]

Adds flake.nix and flake.lock so siomon can be built and used on NixOS or any system with Nix, without manual setup.

Flake outputs

Output	Description
packages.{x86_64,aarch64}-linux.default	The sio binary
packages.{x86_64,aarch64}-linux.sinfo-io-kmod	sinfo_io.ko against the default nixpkgs kernel
overlays.default	Adds pkgs.siomon to a nixpkgs instance
lib.{system}.mkSinfoIoKmod	Factory to build sinfo_io.ko against any kernel

Usage

Run without installing:

nix run github:level1techs/siomon

Use the overlay in a NixOS or home-manager config:

nixpkgs.overlays = [ inputs.siomon.overlays.default ];

Notes

• cargoLock.lockFile = ./Cargo.lock is used instead of cargoHash,
  so no hash needs updating when dependencies change.
• nixpkgs-unstable is required; Rust ≥ 1.85 is not yet
  in a stable nixpkgs channel.

Flake maintenance

Maintenance of flake is minimal since only version string is required to match the Cargo.toml version

[vinylen]

I just saw that we already have a nixpkgs version.. https://search.nixos.org/packages?channel=unstable&query=siomon&show=siomon

Closing this :)

[emansom]

Hey @vinylen, thanks for putting this together! Nice to see NixOS interest.

Just wanted to point you to some existing work around distro packaging:

• There's a broader discussion on distro/OS packaging in Distro/OS packaging #4
• There are open PRs for automated release workflows for AUR and PPA, both derived from PR #24

Our target is to follow the way each distro officially manages and distributes packages through its own package manager and repositories. For NixOS, that means upstreaming to Nixpkgs — the central package set that nix and NixOS pull from — rather than maintaining a flake in-tree (see the Nixpkgs manual).

What we'd love is an automated GitHub Actions workflow — similar to the AUR and PPA ones — that opens a PR against Nixpkgs from a temporary branch on each release. The approach would follow the same pattern from PR #24: a templated packaging/nix/flake.nix with placeholder values (version, hash, etc.) that the workflow sed-substitutes with actual release values, pushes to a temporary branch, and opens a PR against Nixpkgs. Same idea as how the AUR workflow substitutes pkgver/_tag/pkgrel into the PKGBUILD template, or the PPA workflow rewrites debian/changelog and debian/control.

Some prior art and tooling around automated Nixpkgs contributions that might be useful:

• Discussion about auto-updating packages NixOS/nixpkgs#467806
• https://github.com/nix-community/nixpkgs-update
• https://nix-community.github.io/nixpkgs-update/

Would you be up for taking a stab at that kind of workflow? Would be great to have Nix covered alongside AUR and PPA!

[emansom]

I just saw that we already have a nixpkgs version.. https://search.nixos.org/packages?channel=unstable&query=siomon&show=siomon

Closing this :)

Hey @sheevy, thanks for getting siomon into Nixpkgs (NixOS/nixpkgs#501034) — that's awesome!

Since you're already familiar with the Nixpkgs contribution process, would you be interested in contributing an automated GitHub Actions workflow that keeps the Nixpkgs package up to date on new siomon releases?

As described above, the idea is to follow the same pattern we're setting up for AUR and PPA (derived from PR #24): a templated packaging/nix/flake.nix with placeholder values that the workflow sed-substitutes with actual release values, pushes to a temporary branch, and opens a PR against Nixpkgs automatically.

Some tooling and context that might be helpful:

• Discussion about auto-updating packages NixOS/nixpkgs#467806
• https://github.com/nix-community/nixpkgs-update
• https://nix-community.github.io/nixpkgs-update/

You'd be the perfect person for this since you already know how the package is structured in Nixpkgs. Would love to have you on board!

[vinylen]

I think that auto updating for siomon in nixpkgs is already implemented by the maintainer - https://github.com/NixOS/nixpkgs/blob/nixos-unstable/pkgs/by-name/si/siomon/package.nix#L27

[sheevy]

Hey @emansom

As far as I understand, my original PR already handles that, see my comments:
NixOS/nixpkgs#501034 (comment)
NixOS/nixpkgs#501034 (comment)

[emansom]

I think that auto updating for siomon in nixpkgs is already implemented by the maintainer - https://github.com/NixOS/nixpkgs/blob/nixos-unstable/pkgs/by-name/si/siomon/package.nix#L27

Hey @emansom

As far as I understand, my original PR already handles that, see my comments: NixOS/nixpkgs#501034 (comment) NixOS/nixpkgs#501034 (comment)

Oh very meta. Very interesting. Even better! Apologies, I should've researched a bit more before. Let's see if that works on the next tagged version!

[emansom]

Let's see if that works on the next tagged version!

Yep, automation works. Cool!

NixOS/nixpkgs#505942

[sheevy]

Indeed, but it took a while.
According to Nix folks they are not opposed to having our own automation. However, it would require involving a someone with commit rights to nixpkgs, while having their bot making a PR is lighter, and only a maintainer is required.
So for now I would stick with the existing setup.