nixos/preload: init

- [c2FmZQ](https://github.com/c2FmZQ/c2FmZQ/), an application that can securely encrypt, store, and share files, including but not limited to pictures and videos. Available as [services.c2fmzq-server](#opt-services.c2fmzq-server.enable).

- [preload](http://sourceforge.net/projects/preload), a service that makes applications run faster by prefetching binaries and shared objects.  Available as [services.preload](#opt-services.preload.enable).

## Backward Incompatibilities {#sec-release-23.11-incompatibilities}

- `services.postgresql.ensurePermissions` has been deprecated in favor of `services.postgresql.ensureUsers.*.ensureDBOwnership` which simplifies the setup of database owned by a certain system user

  ./services/misc/podgrab.nix

  ./services/misc/polaris.nix

  ./services/misc/portunus.nix

  ./services/misc/preload.nix

  ./services/misc/prowlarr.nix

  ./services/misc/pufferpanel.nix

  ./services/misc/pykms.nix

{ config, lib, pkgs, ... }:

with lib;

let

  cfg = config.services.preload;

in {

  meta = { maintainers = pkgs.preload.meta.maintainers; };

  options.services.preload = {

    enable = mkEnableOption "preload";

    package = mkPackageOption pkgs "preload" { };

  };

  config = mkIf cfg.enable {

    systemd.services.preload = {

      description = "Loads data into ram during idle time of CPU.";

      wantedBy = [ "multi-user.target" ];

      serviceConfig = {

        EnvironmentFile = "${cfg.package}/etc/conf.d/preload";

        ExecStart = "${getExe cfg.package} --foreground $PRELOAD_OPTS";

        Type = "simple";

        # Only preload data during CPU idle time

        IOSchedulingClass = 3;

        DynamicUser = true;

        StateDirectory = "preload";

      };

    };

  };

}