nixpkgs/nixos/tests/sysinit-reactivation.nix

# This runs to two scenarios but in one tests:
# - A post-sysinit service needs to be restarted AFTER tmpfiles was restarted.
# - A service needs to be restarted BEFORE tmpfiles is restarted

{ lib, ... }:

let
  makeGeneration = generation: {
    "${generation}".configuration = {
      systemd.services.pre-sysinit-before-tmpfiles.environment.USER =
        lib.mkForce "${generation}-tmpfiles-user";

      systemd.services.pre-sysinit-after-tmpfiles.environment = {
        NEEDED_PATH = lib.mkForce "/run/${generation}-needed-by-pre-sysinit-after-tmpfiles";
        PATH_TO_CREATE = lib.mkForce "/run/${generation}-needed-by-post-sysinit";
      };

      systemd.services.post-sysinit.environment = {
        NEEDED_PATH = lib.mkForce "/run/${generation}-needed-by-post-sysinit";
        PATH_TO_CREATE = lib.mkForce "/run/${generation}-created-by-post-sysinit";
      };

      systemd.tmpfiles.settings.test = lib.mkForce {
        "/run/${generation}-needed-by-pre-sysinit-after-tmpfiles".f.user =
          "${generation}-tmpfiles-user";
      };
    };
  };
in

{

  name = "sysinit-reactivation";

  meta.maintainers = with lib.maintainers; [ nikstur ];

  nodes.machine = { config, lib, pkgs, ... }: {
    systemd.services.pre-sysinit-before-tmpfiles = {
      wantedBy = [ "sysinit.target" ];
      requiredBy = [ "sysinit-reactivation.target" ];
      before = [ "systemd-tmpfiles-setup.service" "systemd-tmpfiles-resetup.service" ];
      unitConfig.DefaultDependencies = false;
      serviceConfig.Type = "oneshot";
      serviceConfig.RemainAfterExit = true;
      environment.USER = "tmpfiles-user";
      script = "${pkgs.shadow}/bin/useradd $USER";
    };

    systemd.services.pre-sysinit-after-tmpfiles = {
      wantedBy = [ "sysinit.target" ];
      requiredBy = [ "sysinit-reactivation.target" ];
      after = [ "systemd-tmpfiles-setup.service" "systemd-tmpfiles-resetup.service" ];
      unitConfig.DefaultDependencies = false;
      serviceConfig.Type = "oneshot";
      serviceConfig.RemainAfterExit = true;
      environment = {
        NEEDED_PATH = "/run/needed-by-pre-sysinit-after-tmpfiles";
        PATH_TO_CREATE = "/run/needed-by-post-sysinit";
      };
      script = ''
        if [[ -e $NEEDED_PATH ]]; then
          touch $PATH_TO_CREATE
        fi
      '';
    };

    systemd.services.post-sysinit = {
      wantedBy = [ "default.target" ];
      serviceConfig.Type = "oneshot";
      serviceConfig.RemainAfterExit = true;
      environment = {
        NEEDED_PATH = "/run/needed-by-post-sysinit";
        PATH_TO_CREATE = "/run/created-by-post-sysinit";
      };
      script = ''
        if [[ -e $NEEDED_PATH ]]; then
          touch $PATH_TO_CREATE
        fi
      '';
    };

    systemd.tmpfiles.settings.test = {
      "/run/needed-by-pre-sysinit-after-tmpfiles".f.user =
        "tmpfiles-user";
    };

    specialisation = lib.mkMerge [
      (makeGeneration "second")
      (makeGeneration "third")
    ];
  };

  testScript = { nodes, ... }: ''
    def switch(generation):
      toplevel = "${nodes.machine.system.build.toplevel}";
      machine.succeed(f"{toplevel}/specialisation/{generation}/bin/switch-to-configuration switch")

    machine.wait_for_unit("default.target")
    machine.succeed("test -e /run/created-by-post-sysinit")

    switch("second")
    machine.succeed("test -e /run/second-created-by-post-sysinit")

    switch("third")
    machine.succeed("test -e /run/third-created-by-post-sysinit")
  '';
}