writeZone does not work when importing as flake

[nix-community]

writeZone does not work when importing as flake

[ncfavier]

writeZone relies on pkgs.writeTextFile, which is only available when the full nixpkgs is instantiated (import "${nixpkgs}" { system = "some-system"; }).

What do you mean? How are you importing dns/default.nix?

[AluisioASG]

Here's a minimal example:

{
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
  inputs.dns = { url = "github:kirelagin/nix-dns"; inputs.nixpkgs.follows = "nixpkgs"; };
  outputs = { self, nixpkgs, dns }: {
    defaultPackage.x86_64-linux = dns.lib.writeZone "example.invalid" {
      SOA = { nameServer = "ns.example.invalid"; adminEmail = "[email protected]"; serial = 1; };
    };
  };
}

nix build results in:

error: --- EvalError ----------------------------------------------------------------- nix
at: (32:5) in file: /nix/store/lnphin86szjd22maxjcj51kk13gf34nl-source/dns/default.nix

    31|   writeZone = name: zone:
    32|     pkgs.writeTextFile {
      |     ^
    33|       name = "${name}.zone";
attribute 'writeTextFile' missing

writeZone seems to be the only part of nix-dns that accesses something out of pkgs.lib (which in flake mode is the lib output of the Nixpkgs flake) and that's why only it breaks.

[ncfavier]

Hm. And there's no way to actually import nixpkgs in pure mode without specifying what system we're running on, which the lib flake attribute doesn't support.

Maybe we could use builtins.toFile instead of pkgs.writeTextFile, as the zone shouldn't depend on any derivations?

[kirelagin]

Hmmmm, I think the correct solution here would be to move writeZone out of the lib output into some other output and do the full eachDefaultSystem dance.