Import directories automatically without default.nix

[llakala]

We've already created an importAll function to import everything in a directory:

importAll =
  dir:
    lib.mapAttrsToList
    (
      n: _: dir + "/${n}"
    )
    (builtins.readDir dir);

This function was a really great reference: https://github.com/Julow/env/blob/e4674d5870c5c15861f9410f8cd11a255f35b117/common.nix#L7 Next, we need to create a wrapper function so we can pass in a list of paths, and importAll on each of those paths. Here's a beta version of the wrapper function that might work, but more investigation is needed:

lib.concatLists (map importAll dirs);

[llakala]

The scope of this one is a bit past us since it's using recursion which we don't need, but still something to be aware of https://github.com/evanjs/nixos_cfg/blob/master/config/new-modules/default.nix

[llakala]

Update, importing a single folder now properly excludes anything that isn't a nix file:

importNixFiles = dir:
  lib.mapAttrsToList
  (
     file: _: dir + "/${file}"
  )
  (lib.filterAttrs
    (
      file: _: lib.hasSuffix ".nix" file
    )
    (builtins.readDir dir)
  );

We also have a good version of importing lots of different folders at once:

  importFolders = dirs:
  lib.concatLists
  (map importNixFiles dirs);

However, there are somewhat large issues. Currently these are:

• Empty lists don't work properly. They work inside nix repl, but not within the purview of modules. More research is needed on this

• Other things, like single files and modules like inputs.disko.nixosModules.disko

  It's fine if handling modules is out of scope, but empty lists should work properly, and hopefully single files can as well.

[llakala]

Update, empty lists now work properly using an if statement. Update, empty lists now work properly using an if statement. The function could hypothetically be improved in the future, but I'm happy with where it's at now. HerThe function could hypothetically be improved in the future, but I'm happy with where it's at now. Here it is for posterity:

importNixFiles = dir:
  if builtins.pathExists dir then # If folder has contents
    lib.mapAttrsToList
    (file: _: dir + "/${file}")
    (lib.filterAttrs
      (file: _: lib.hasSuffix ".nix" file) # Only import .nix files
      (builtins.readDir dir)
    )
  else # If directory is empty, return empty list
    [];

For now, this is good enough for our needs. Future scope could include:

• Appending nixos and home to the base and hostName folders, so we can import both properly
• Properly handling single files, sets, and modules from inputs by passing them directly into modules
• Adding this as a lib function, rather than just a declared function in the mkHosts file