turboprop/lib/app-template.nix

{
  builders,
  charts,
  pkgs,
}: rec {
  mkImageAttrs = image:
    with builtins; let
      vals = pkgs.lib.strings.splitString ":" image;

      # Tag may contain ":", such as `rolling@sha256:...`.
      # Or it may not. So this contortion deal with both scenarios
      # using `sublist`.
      tag = with builtins;
        concatStringsSep ":"
        (filter (x: typeOf x != "list")
          (pkgs.lib.lists.sublist 1 2 vals));
    in {
      repository = elemAt vals 0;
      inherit tag;
    };

  mkExistingClaim = pvc: subPath: {
    existingClaim = pvc;
    inherit subPath;
  };

  build = {
    namespace,
    name,
    mainImage,
    values ? {},
    apiVersions ? [],
    kubeVersion ? pkgs.kubernetes.version,
  }:
    builders.helmChart {
      inherit name namespace apiVersions;
      chart = charts.bjw-s.app-template;
      values =
        pkgs.lib.attrsets.recursiveUpdate
        {
          controllers.main.containers.main.image =
            mkImageAttrs mainImage;
        }
        values;
    };
}