Using relative path to a "type" file in dhallToNix about dhall-nix HOT 5 CLOSED

Yeah, I have ran into this issue myself. One way to address this problem is to interpolate the relative path to the Dhall expression, like this:

let
  pkgs = import <nixpkgs> { };
  inherit (pkgs) dhallToNix;

in
  { vbox = (dhallToNix "{ headless = True, vcpu = +2 } : ${../../../ops/VirtualBox.dhall}");
  }

That will then ensure that Nix adds ../../../ops/VirtualBox.dhall to the /nix/store as some /nix/store/....-VirtualBox.dhall path and Nix will then interpolate path that into the string giving you the following final Dhall expression

{ headless = True, vcpu = +2 } : /nix/store/...-VirtualBox.dhall

The other benefit of doing this is that Nix will then correctly detect that the VirtualBox.dhall file is a build-time dependency of the Dhall expression, ensuring that the import will be present on any machine that evaluates that Dhall expression.

from dhall-nix.

Thanks. Our problem is that the ../../ops/VirtualBox.dhall file also uses many other type-files in other places in the directory tree. Will this trick work for an entire directory tree?

from dhall-nix.

Oh, I see the issue. So if all of the Dhall expressions are located within a single subdirectory (such as ../../../ops) and they all reference each other by relative paths then you can do this instead:

let
  pkgs = import <nixpkgs> { };
  inherit (pkgs) dhallToNix;

in
  { vbox = (dhallToNix "{ headless = True, vcpu = +2 } : ${../../../ops}/VirtualBox.dhall");
  }

Then the entire ../../../ops directory will be copied to the /nix/store and the VirtualBox.dhall dependency will be replaced with an absolute path within that directory. Every transitive dependency of VirtualBox.dhall should be correctly referenced via relative paths.

from dhall-nix.

Thanks! works great!

from dhall-nix.

You're welcome! :)

from dhall-nix.