environment.systemPackages ignored about arion HOT 3 CLOSED

See #40

from arion.

There's multiple ways one might make use of NixOS configuration to create a docker image. You can run your service as a NixOS service and enable nixos.useSystemd to set the docker command to systemd. That's the most predictable way to use NixOS. Alternatively you can wire up service.command or image.command like this for example.

If you're not using NixOS by calling its init systemd, there's always a chance that you need something that's normally taken care of by NixOS, like installing certain packages or background services (such as cleaning tmp, reaping zombies etc etc).

So it really depends on your use case. I currently recommend nixos.useSystemd for most cases but if you need to deploy lightweight images, you'll have to use the image options to do some things manually instead. Proper images are a recent addition to Arion, so your mileage may vary with that feature.

from arion.

Alright, thanks!

If someone runs into a similar issue, here's a working example:

{ pkgs, ... }:
{
  docker-compose.services = {
    webserver = { config, pkgs, ... }: {
      nixos.configuration = {config, pkgs, ...}: {
        boot.isContainer = true;
        environment.systemPackages = with pkgs; [
          # will be evaluated if service.command isn't set
          tree
        ];
        system.build.someEntryFun = pkgs.writeScript "someEntryFun" ''
          #!${pkgs.bash}/bin/bash
          ${pkgs.cowsay}/bin/cowsay "dependencies in this script are fetched automatically"
        '';
      };
      nixos.useSystemd = true;
      service = {
        command = [ config.nixos.build.someEntryFun ];
        useHostStore = true;
      };
    };
  };
}

if nixos.command is commented out calling docker exec -it <some-hash> tree will be possible (working since #40).

from arion.