nixos-configs/devices/servivi/modules/arion/default.nix

{
  arion,
  config,
  lib,
  ...
} @ inputs:
with lib;
with builtins; let
  user = config.vars.user;
  configPath = "/var/lib/arion";
in {
  imports = [arion.nixosModules.arion];

  users.extraUsers.${user}.extraGroups = ["docker"];

  services.borgbackup.configs.arion = {
    paths = [configPath];
    exclude = ["**/lineageos*"];
  };

  virtualisation = {
    docker = {
      enable = true;
      storageDriver = "btrfs";
    };

    arion = {
      backend = "docker";

      projects = let
        composeFiles =
          filter (n: hasSuffix "compose.nix" (toString n))
          (filesystem.listFilesRecursive ./.);

        projects = filterAttrs (n: v: v.enabled or true) (listToAttrs (map (p: {
            name = elemAt (match ".*\/(.*)\/compose\.nix" (toString p)) 0;

            value = import p (inputs
              // {
                rwPath =
                  configPath
                  + "/"
                  + elemAt (match "[^-]*-(.*)" "${dirOf p}") 0;
              });
          })
          composeFiles));
      in
        mapAttrs (n: v: {
          # https://docs.hercules-ci.com/arion/options
          settings = {
            enableDefaultNetwork = v.enableDefaultNetwork or true;
            networks = optionalAttrs (hasAttr "networks" v) v.networks;

            services =
              mapAttrs (n': v': {
                image = optionalAttrs (hasAttr "customImage" v') v'.customImage;
                service = filterAttrs (n: v: n != "customImage") v';
              })
              v.services;
          };
        })
        projects;
    };
  };
}