Copy .nix files to /etc/nixos as well? about terraform-nixos HOT 5 OPEN

Some sort of find / scp / rsync combo is not good , because I also have some tests.nix that is is not referenced through configuration.nix. And then digital-ocean-image.nix is also something that I don't need to copy (since it is already there).

from terraform-nixos.

The best option is to delete /etc/nixos on the target machine. You can do that by using the "remote-exec" provisioner, or by adding it in a systemd unit in the machine configuration.nix.

It would be nice if it was possible to copy all the nix files onto the server, so that it can be rebuilt manually, but that's quite difficult to achieve. To reproduce the config, deploy_nixos would have to capture not only the configuration.nix, but also be able to follow all the imported modules. And which version of nixpkgs is being used.

from terraform-nixos.

I came up with this "contraption" 🙂

{ pkgs ? import <nixpkgs> {}, ... }:
let
  lib = pkgs.lib;

  resolveOne = file: let p = pkgs.callPackage file {}; in lib.filter (x: !lib.hasPrefix "/nix" (builtins.toPath x)) (if lib.hasAttr "imports" p then p.imports else []);
  oneStep = result: lib.unique (lib.foldl' (x: y:  x ++ resolveOne y) result result);
  resolve = input: let resolveRec = x: let y = oneStep x; in if lib.length x == lib.length y then y else resolveRec y; in resolveRec [ input ];

  getPrefix = main: let file = builtins.toPath main; name = builtins.baseNameOf file; root = lib.replaceStrings [ "/${name}" ] [ ""] file; in root;
  getRelativePaths = main: let prefix = getPrefix main; in map (x: lib.replaceStrings [ prefix ] [ "." ] (builtins.toPath x)) (resolve main);
  getRelativePathsStr = main: builtins.concatStringsSep "\n" (getRelativePaths main);
in
pkgs.mkShell {
  shellHook = ''
    echo "ssh machine rm -rf /etc/nixos"
    echo "${getRelativePathsStr ./configuration.nix}" | xargs -n 1 -I {} echo "ssh machine mkdir -p /etc/nixos/$(pathname {} 2>/dev/null) ; scp {} machine:/etc/nixos/{}"
  '';
}

Obviously this is just an approximation, since nixpkgs might be different on remote machine.

from terraform-nixos.

🙈

Another thing you can do is set nix.nixPath = [ "nixpkgs=${pkgs}" ]; so nixpkgs also get pushed and set to NIX_PATH.

from terraform-nixos.

There is also https://search.nixos.org/options?channel=20.09&show=system.copySystemConfiguration&from=0&size=30&sort=relevance&query=copy , but that only works if the config is self-contained into a single file.

from terraform-nixos.