# Test configuration switching.

import ./make-test-python.nix ({ pkgs, ...} : {
  name = "switch-test";
  meta = with pkgs.lib.maintainers; {
    maintainers = [ gleber das_j ];
  };

  nodes = {
    machine = { pkgs, lib, ... }: {
      users.mutableUsers = false;

      specialisation = rec {
        simpleService.configuration = {
          systemd.services.test = {
            wantedBy = [ "multi-user.target" ];
            serviceConfig = {
              Type = "oneshot";
              RemainAfterExit = true;
              ExecStart = "${pkgs.coreutils}/bin/true";
            };
          };
        };

        simpleServiceModified.configuration = {
          imports = [ simpleService.configuration ];
          systemd.services.test.serviceConfig.X-Test = true;
        };

        simpleServiceNostop.configuration = {
          imports = [ simpleService.configuration ];
          systemd.services.test.stopIfChanged = false;
        };

        simpleServiceReload.configuration = {
          imports = [ simpleService.configuration ];
          systemd.services.test = {
            reloadIfChanged = true;
            serviceConfig.ExecReload = "${pkgs.coreutils}/bin/true";
          };
        };

        simpleServiceNorestart.configuration = {
          imports = [ simpleService.configuration ];
          systemd.services.test.restartIfChanged = false;
        };

        mount.configuration = {
          systemd.mounts = [
            {
              description = "Testmount";
              what = "tmpfs";
              type = "tmpfs";
              where = "/testmount";
              options = "size=1M";
              wantedBy = [ "local-fs.target" ];
            }
          ];
        };

        mountModified.configuration = {
          systemd.mounts = [
            {
              description = "Testmount";
              what = "tmpfs";
              type = "tmpfs";
              where = "/testmount";
              options = "size=10M";
              wantedBy = [ "local-fs.target" ];
            }
          ];
        };

        timer.configuration = {
          systemd.timers.test-timer = {
            wantedBy = [ "timers.target" ];
            timerConfig.OnCalendar = "@1395716396"; # chosen by fair dice roll
          };
          systemd.services.test-timer = {
            serviceConfig = {
              Type = "oneshot";
              ExecStart = "${pkgs.coreutils}/bin/true";
            };
          };
        };

        timerModified.configuration = {
          imports = [ timer.configuration ];
          systemd.timers.test-timer.timerConfig.OnCalendar = lib.mkForce "Fri 2012-11-23 16:00:00";
        };

        path.configuration = {
          systemd.paths.test-watch = {
            wantedBy = [ "paths.target" ];
            pathConfig.PathExists = "/testpath";
          };
          systemd.services.test-watch = {
            serviceConfig = {
              Type = "oneshot";
              ExecStart = "${pkgs.coreutils}/bin/touch /testpath-modified";
            };
          };
        };

        pathModified.configuration = {
          imports = [ path.configuration ];
          systemd.paths.test-watch.pathConfig.PathExists = lib.mkForce "/testpath2";
        };

        slice.configuration = {
          systemd.slices.testslice.sliceConfig.MemoryMax = "1"; # don't allow memory allocation
          systemd.services.testservice = {
            serviceConfig = {
              Type = "oneshot";
              RemainAfterExit = true;
              ExecStart = "${pkgs.coreutils}/bin/true";
              Slice = "testslice.slice";
            };
          };
        };

        sliceModified.configuration = {
          imports = [ slice.configuration ];
          systemd.slices.testslice.sliceConfig.MemoryMax = lib.mkForce null;
        };
      };
    };

    other = {
      users.mutableUsers = true;
    };
  };

  testScript = { nodes, ... }: let
    originalSystem = nodes.machine.config.system.build.toplevel;
    otherSystem = nodes.other.config.system.build.toplevel;
    machine = nodes.machine.config.system.build.toplevel;

    # Ensures failures pass through using pipefail, otherwise failing to
    # switch-to-configuration is hidden by the success of `tee`.
    stderrRunner = pkgs.writeScript "stderr-runner" ''
      #! ${pkgs.runtimeShell}
      set -e
      set -o pipefail
      exec env -i "$@" | tee /dev/stderr
    '';
  in /* python */ ''
    def switch_to_specialisation(system, name, action="test"):
        if name == "":
            stc = f"{system}/bin/switch-to-configuration"
        else:
            stc = f"{system}/specialisation/{name}/bin/switch-to-configuration"
        out = machine.succeed(f"{stc} {action} 2>&1")
        assert_lacks(out, "switch-to-configuration line")  # Perl warnings
        return out

    def assert_contains(haystack, needle):
        if needle not in haystack:
            print("The haystack that will cause the following exception is:")
            print("---")
            print(haystack)
            print("---")
            raise Exception(f"Expected string '{needle}' was not found")

    def assert_lacks(haystack, needle):
        if needle in haystack:
            print("The haystack that will cause the following exception is:")
            print("---")
            print(haystack, end="")
            print("---")
            raise Exception(f"Unexpected string '{needle}' was found")


    machine.succeed(
        "${stderrRunner} ${originalSystem}/bin/switch-to-configuration test"
    )
    machine.succeed(
        "${stderrRunner} ${otherSystem}/bin/switch-to-configuration test"
    )

    with subtest("services"):
        switch_to_specialisation("${machine}", "")
        # Nothing happens when nothing is changed
        out = switch_to_specialisation("${machine}", "")
        assert_lacks(out, "stopping the following units:")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_lacks(out, "reloading the following units:")
        assert_lacks(out, "\nrestarting the following units:")
        assert_lacks(out, "\nstarting the following units:")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")

        # Start a simple service
        out = switch_to_specialisation("${machine}", "simpleService")
        assert_lacks(out, "stopping the following units:")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_contains(out, "reloading the following units: dbus.service\n")  # huh
        assert_lacks(out, "\nrestarting the following units:")
        assert_lacks(out, "\nstarting the following units:")
        assert_contains(out, "the following new units were started: test.service\n")
        assert_lacks(out, "as well:")

        # Not changing anything doesn't do anything
        out = switch_to_specialisation("${machine}", "simpleService")
        assert_lacks(out, "stopping the following units:")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_lacks(out, "reloading the following units:")
        assert_lacks(out, "\nrestarting the following units:")
        assert_lacks(out, "\nstarting the following units:")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")

        # Restart the simple service
        out = switch_to_specialisation("${machine}", "simpleServiceModified")
        assert_contains(out, "stopping the following units: test.service\n")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_lacks(out, "reloading the following units:")
        assert_lacks(out, "\nrestarting the following units:")
        assert_contains(out, "\nstarting the following units: test.service\n")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")

        # Restart the service with stopIfChanged=false
        out = switch_to_specialisation("${machine}", "simpleServiceNostop")
        assert_lacks(out, "stopping the following units:")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_lacks(out, "reloading the following units:")
        assert_contains(out, "\nrestarting the following units: test.service\n")
        assert_lacks(out, "\nstarting the following units:")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")

        # Reload the service with reloadIfChanged=true
        out = switch_to_specialisation("${machine}", "simpleServiceReload")
        assert_lacks(out, "stopping the following units:")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_contains(out, "reloading the following units: test.service\n")
        assert_lacks(out, "\nrestarting the following units:")
        assert_lacks(out, "\nstarting the following units:")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")

        # Nothing happens when restartIfChanged=false
        out = switch_to_specialisation("${machine}", "simpleServiceNorestart")
        assert_lacks(out, "stopping the following units:")
        assert_contains(out, "NOT restarting the following changed units: test.service\n")
        assert_lacks(out, "reloading the following units:")
        assert_lacks(out, "\nrestarting the following units:")
        assert_lacks(out, "\nstarting the following units:")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")

        # Dry mode shows different messages
        out = switch_to_specialisation("${machine}", "simpleService", action="dry-activate")
        assert_lacks(out, "stopping the following units:")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_lacks(out, "reloading the following units:")
        assert_lacks(out, "\nrestarting the following units:")
        assert_lacks(out, "\nstarting the following units:")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")
        assert_contains(out, "would start the following units: test.service\n")

    with subtest("mounts"):
        switch_to_specialisation("${machine}", "mount")
        out = machine.succeed("mount | grep 'on /testmount'")
        assert_contains(out, "size=1024k")
        out = switch_to_specialisation("${machine}", "mountModified")
        assert_lacks(out, "stopping the following units:")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_contains(out, "reloading the following units: testmount.mount\n")
        assert_lacks(out, "\nrestarting the following units:")
        assert_lacks(out, "\nstarting the following units:")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")
        # It changed
        out = machine.succeed("mount | grep 'on /testmount'")
        assert_contains(out, "size=10240k")

    with subtest("timers"):
        switch_to_specialisation("${machine}", "timer")
        out = machine.succeed("systemctl show test-timer.timer")
        assert_contains(out, "OnCalendar=2014-03-25 02:59:56 UTC")
        out = switch_to_specialisation("${machine}", "timerModified")
        assert_lacks(out, "stopping the following units:")
        assert_lacks(out, "reloading the following units:")
        assert_contains(out, "restarting the following units: test-timer.timer\n")
        assert_lacks(out, "\nstarting the following units:")
        assert_lacks(out, "the following new units were started:")
        assert_lacks(out, "as well:")
        # It changed
        out = machine.succeed("systemctl show test-timer.timer")
        assert_contains(out, "OnCalendar=Fri 2012-11-23 16:00:00")

    with subtest("paths"):
        out = switch_to_specialisation("${machine}", "path")
        assert_contains(out, "stopping the following units: test-timer.timer\n")
        assert_lacks(out, "NOT restarting the following changed units:")
        assert_lacks(out, "reloading the following units:")
        assert_lacks(out, "\nrestarting the following units:")
        assert_lacks(out, "\nstarting the following units:")
        assert_contains(out, "the following new units were started: test-watch.path")
        assert_lacks(out, "as well:")
        machine.fail("test -f /testpath-modified")

        # touch the file, unit should be triggered
        machine.succeed("touch /testpath")
        machine.wait_until_succeeds("test -f /testpath-modified")
        machine.succeed("rm /testpath /testpath-modified")
        switch_to_specialisation("${machine}", "pathModified")
        machine.succeed("touch /testpath")
        machine.fail("test -f /testpath-modified")
        machine.succeed("touch /testpath2")
        machine.wait_until_succeeds("test -f /testpath-modified")

    # This test ensures that changes to slice configuration get applied.
    # We test this by having a slice that allows no memory allocation at
    # all and starting a service within it. If the service crashes, the slice
    # is applied and if we modify the slice to allow memory allocation, the
    # service should successfully start.
    with subtest("slices"):
        machine.succeed("echo 0 > /proc/sys/vm/panic_on_oom")  # allow OOMing
        out = switch_to_specialisation("${machine}", "slice")
        machine.fail("systemctl start testservice.service")
        out = switch_to_specialisation("${machine}", "sliceModified")
        machine.succeed("systemctl start testservice.service")
        machine.succeed("echo 1 > /proc/sys/vm/panic_on_oom")  # disallow OOMing
  '';
})