mail2-nixos-config/auto-upgrade.nix
2019-07-03 22:31:48 +02:00

120 lines
3.5 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let cfg = config.system.autoUpgrade; in
{
options = {
system.autoUpgrade = {
enable = mkOption {
type = types.bool;
default = false;
description = ''
Whether to periodically upgrade NixOS to the latest
version. If enabled, a systemd timer will run
<literal>nixos-rebuild switch --upgrade</literal> once a
day.
'';
};
channel = mkOption {
type = types.nullOr types.str;
default = null;
example = https://nixos.org/channels/nixos-14.12-small;
description = ''
The URI of the NixOS channel to use for automatic
upgrades. By default, this is the channel set using
<command>nix-channel</command> (run <literal>nix-channel
--list</literal> to see the current value).
'';
};
flags = mkOption {
type = types.listOf types.str;
default = [];
example = [ "-I" "stuff=/home/alice/nixos-stuff" "--option" "extra-binary-caches" "http://my-cache.example.org/" ];
description = ''
Any additional flags passed to <command>nixos-rebuild</command>.
'';
};
dates = mkOption {
default = "04:40";
type = types.str;
description = ''
Specification (in the format described by
<citerefentry><refentrytitle>systemd.time</refentrytitle>
<manvolnum>7</manvolnum></citerefentry>) of the time at
which the update will occur.
'';
};
allowReboot = mkOption {
default = false;
type = types.bool;
description = ''
Shall the system be rebooted if the new configuration
uses a different kernel, kernel modules or initrd
than the booted system?
'';
};
};
};
config = {
system.autoUpgrade.flags =
[ "--no-build-output" ]
++ (if cfg.channel == null
then [ "--upgrade" ]
else [ "-I" "nixpkgs=${cfg.channel}/nixexprs.tar.xz" ]);
systemd.services.nixos-upgrade = {
description = "NixOS Upgrade";
restartIfChanged = false;
unitConfig.X-StopOnRemoval = false;
serviceConfig.Type = "oneshot";
environment = config.nix.envVars //
{ inherit (config.environment.sessionVariables) NIX_PATH;
HOME = "/root";
} // config.networking.proxy.envVars;
path = [ pkgs.gnutar pkgs.xz.bin pkgs.gitMinimal config.nix.package.out ];
script = ''
${lib.optionalString cfg.allowReboot ''
set -euo pipefail
set -x
T=$(mktemp -d)
cd "$T"
${config.system.build.nixos-rebuild}/bin/nixos-rebuild build ${toString cfg.flags}
booted="$(${pkgs.coreutils}/bin/readlink /run/booted-system/{initrd,kernel,kernel-modules})"
built="$(${pkgs.coreutils}/bin/readlink result/{initrd,kernel,kernel-modules})"
cd /tmp
rm -rf "$T"
if [ "$booted" = "$built" ]; then
${config.system.build.nixos-rebuild}/bin/nixos-rebuild switch ${toString cfg.flags}
else
${config.system.build.nixos-rebuild}/bin/nixos-rebuild boot ${toString cfg.flags}
/run/current-system/sw/bin/shutdown -r +1
fi
''}
${lib.optionalString (!cfg.allowReboot) "${config.system.build.nixos-rebuild}/bin/nixos-rebuild switch ${toString cfg.flags}"}
'';
startAt = optional cfg.enable cfg.dates;
};
};
}