This nixos module restores command-not-found behavior on flake-based nixos systems.

It works by using the name of the channel you are following and your nixpkgs rev to find and download the programdb from the channel infrastructure. This download happens at runtime via a systemd service. So long as you follow a branch of nixpkgs which is also a channel, this approach should always work.

Installation

Import nixosModules.flake-programdb from this flake into your nixos configuration through imports or the nixosSystem function's modules argument, and set:

flake-programdb.enable = true;

# Unnecessary if following nixos-XX.YY.
flake-programdb.channel = "nixos-unstable";

Full example:

{
  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
  inputs.flake-programdb.url = "github:tejing1/flake-programdb";
  outputs = { nixpkgs, flake-programdb, ...}: {
    hostname = nixpkgs.lib.nixosSystem {
      system = "x86-64-linux";
      modules = [
        ./configuration.nix
        flake-programdb.nixosModules.flake-programdb
        {
          flake-programdb.enable = true;

          # Unnecessary if following nixos-XX.YY.
          flake-programdb.channel = "nixos-unstable";
        }
      ];
    };
  }
}

Options

flake-programdb.enable

Enable the module. Without this set to true, it does nothing. Defaults to false.

flake-programdb.dbDir

Directory in which to store the downloaded programdb and a revision tag for comparison. The directory will be created through tmpfiles.d rules if necessary. Defaults to "/var/cache/programdb".

flake-programdb.channel

Name of the channel whose history should be searched for the right revision of nixpkgs. Defaults to "nixos-" + config.system.nixos.release. Must be set when following anything other than nixos-XX.YY.

flake-programdb.rev

The git revision of nixpkgs to search for in the history of the channel. Defaults to config.system.nixos.revision.