Create a list of directories via Home Manager

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1

I want to create a list of directories that are stored in settings.github-accounts. This is a variable defined and import to my flex.

settings.nix

{
  username = "foo";

  github-accounts = [
    {
      username = "bar";
      email = "bar@exampale.com";
    }
    {
      username = "baz";
      email = "baz@example.com";
    }
  ];
}

I want to use this variable and loop over it and create a directory for each account. (I’m using home.activation for this. If there’s something better and more declarative, please let me know.) I came up with something like this below, but this apparently does not work.

home.nix

  home.activation = {
    init = lib.hm.dag.entryAfter [ "writeBoundary" ] ''
      ${builtins.map(account: "mkdir -p ~/projects/${account.username}") settings.github-accounts}
    '';
  };

I get this error. But why?

error:
       … while calling the 'derivationStrict' builtin

         at /builtin/derivation.nix:9:12: (source not available)

       … while evaluating derivation 'home-manager-generation'
         whose name attribute is located at /nix/store/lwyjz70qh12nq6cb7fixl85vryzxqm3c-source/pkgs/stdenv/generic/make-derivation.nix:353:7

       … while evaluating attribute 'buildCommand' of derivation 'home-manager-generation'

         at /nix/store/lwyjz70qh12nq6cb7fixl85vryzxqm3c-source/pkgs/build-support/trivial-builders/default.nix:98:16:

           97|         enableParallelBuilding = true;
           98|         inherit buildCommand name;
             |                ^
           99|         passAsFile = [ "buildCommand" ]

       (stack trace truncated; use '--show-trace' to show the full trace)

       error: cannot coerce a list to a string
3

Try including a concatStringsSep step using a newline character, and give it the result of your map.

https://nixos.org/manual/nix/stable/language/builtins.html#builtins-concatStringsSep

1 Like
4

Thanks, that worked!