NixOS Configuration ❄️

Getting Started

Note

Before installing, it can be beneficial to add your user to nix.settings.trusted-users (e.g., /etc/nixos/configuration.nix if you just installed), as the nh wrapper sets the options extra-substituters and extra-trusted-public-keys, which are silently ignored if set by non-trusted users. This can significantly reduce the time needed for building.

First you will need an SSH key with access to the sops-protected vault and authentication access to your GitHub account. Place it in ~/.ssh/id_nix.

export NIX_CONFIG="extra-experimental-features = nix-command flakes pipe-operators"
eval $(ssh-agent); ssh-add ~/.ssh/id_nix

nix flake update vault
nix run .#niks -- os boot .#my-hostname
reboot

passwd

Updating the Flake

The update package can be used to update the flake. It updates the flake inputs, locks the inputs defined in releaseLockedInputs to the latest release (including dependants), and updates instances of git fetchers¹ in the config.

nix run .#update

To get around GitHub's API rate limiting, set the GITHUB_TOKEN environment variable before running the script. This should not be necessary if you're just updating once or twice.

The only caveat of this method is that fetchers¹ cannot be used in let...in expressions, as update-nix-fetchgit² cannot handle it.

Manually Updating an Input

Some times you might want to manually update and input; in this case, use the unwrapped update-flake package. This also works on other Nix flakes.

# Update Zed to the latest commit
nix run .#update-flake -- zed

# Update Zed to the latest release
nix run .#update-flake -- --release zed

Module/Feature Structure

{
  self,
  inputs,
  lib',
  ...
}: {
  flake.nixosModules.myModule = {config, pkgs, lib, ...}: {
  };

  flake.homeModules.myModule = {config, pkgs, lib, ...}: {
  };

  perSystem = {
    pkgs,
    lib,
    self',
    ...
  }: {
    # https://birdeehub.github.io/nix-wrapper-modules/md/wrapper-modules.html
    packages.myPackage = inputs.wrapper-modules.wrappers.myPackage.wrap {
      inherit pkgs;
    };
  };
}

nixpkgs Config

Since nixpkgs is instantiated externally in parts.nix (via perSystem), nixpkgs.config cannot be set inside NixOS or Home Manager modules. Instead, place a nixpkgs.nix sidecar next to the feature's default.nix returning a plain attrset:

# features/my-feature/nixpkgs.nix
{ allowedLicenses = [ ... ]; }

parts.nix collects all nixpkgs.nix files under features/ and deep-merges them into the nixpkgs config at instantiation time.

Footnotes

1. https://ryantm.github.io/nixpkgs/builders/fetchers ↩ ↩²

2. https://github.com/expipiplus1/update-nix-fetchgit ↩