In reply to @tomberek:matrix.org
The remote build system is powerful, but doing this and breaking out of the sandbox in a safe way will take some care. But yes, this can be done; I used this as a quick data transformation engine orchestrated by Hydra, you just gotta be careful and ensure you end up with the properties you want.

In reply to @flyx:klacker.eu
can I use Nix Flakes purely as a solution for remote compiling? like, my (otherwise Nix-less) project requires me to build it on a remote machine and I have some hacky rsync-up---compile---rsync-down script which I want to replace with something more sensible, and Nix provides remote building capabilities. so if I write an impure Flake that just calls the system compiler and doesn’t use any Nix features, would this be a feasible solution for remote compiling?

    runBuildOnLinux = pkgs.writeShellApplication {
      name = "run-build-on-linux";
      runtimeInputs = [pkgs.jq];
      text = ''
        target="$1"; shift
        copy_result_back="''${2:-true}"
        flake=$(nix flake metadata --json | jq -r .path)
        if [ "$(uname -s)" = "Linux" ]; then
            # nothing to do, we're on linux already
            exec nix build --json --no-link "$@" -L "$flake#$target" | jq -r '.[0].outputs.out'
            exit 0
        fi

        remote_machine="''${REMOTE_MACHINE:-gloria.home}"
        nix copy --to "ssh-ng://$remote_machine" "$flake"
        out="$(ssh "$remote_machine" nix build --json --no-link -L "$@" "$flake#$target" | jq -r '.[0].outputs.out')"
        if [ "$copy_result_back" = "true" ]; then
            nix copy --no-check-sigs --from "ssh-ng://$remote_machine" "$out"
        fi
        echo "$out"
      '';
    };

is that script

In reply to @flyx:klacker.eu
can I use Nix Flakes purely as a solution for remote compiling? like, my (otherwise Nix-less) project requires me to build it on a remote machine and I have some hacky rsync-up---compile---rsync-down script which I want to replace with something more sensible, and Nix provides remote building capabilities. so if I write an impure Flake that just calls the system compiler and doesn’t use any Nix features, would this be a feasible solution for remote compiling?

Hi! I'm finally migrating my 6 years old nixos config to Flakes! It's mostly going well but I need some help. I used to have an overlay that added nixpkgs-unstable to the nixpkgs.unstable attribute (using fetchTarball to get it). Now, I want to use a flake input instead, and I used an inline module with an overlay to have it exposed in the same place again. I'm trying to make my existing modules compatible with the Flake, so I don't have to go in and change them all.

This all seems to work, except that Nix is refusing to evaluate Unfree packages from Unstable now. It appears as though the nixpkgs.config does not apply to the unstable input the way it used to. So my question is: How do I get this second nixpkgs input to adhere to the same config as my primary one? And by "primary" I guess I mean the one used to make the lib.nixosSystem call.