1 files changed, 81 insertions, 0 deletions

diff --git a/modules/tzupdate.nix b/modules/tzupdate.nix
new file mode 100644
index 00000000..6465d33f
--- /dev/null
+++ b/modules/tzupdate.nix
@@ -0,0 +1,81 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.services.tzupdate;
+in
+{
+  disabledModules = [ "services/misc/tzupdate.nix" ];
+
+  options.services.tzupdate = {
+    enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = ''
+        Enable the tzupdate timezone updating service. This provides
+        a one-shot service which can be activated with systemctl to
+        update the timezone.
+      '';
+    };
+
+    package = lib.mkPackageOption pkgs "tzupdate" { };
+
+    timer.enable = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = ''
+        Enable the tzupdate timer to update the timezone automatically.
+      '';
+    };
+
+    timer.interval = lib.mkOption {
+      type = lib.types.str;
+      default = "hourly";
+      description = ''
+        The interval at which the tzupdate timer should run. See
+        {manpage}`systemd.time(7)` to understand the format.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    # We need to have imperative time zone management for this to work.
+    # This will give users an error if they have set an explicit time
+    # zone, which is better than silently overriding it.
+    time.timeZone = null;
+
+    # We provide a one-shot service that runs at startup once network
+    # interfaces are up, but we can’t ensure we actually have Internet access
+    # at that point. It can also be run manually with `systemctl start tzupdate`.
+    systemd.services.tzupdate = {
+      description = "tzupdate timezone update service";
+      wantedBy = [ "multi-user.target" ];
+      wants = [ "network-online.target" ];
+      after = [ "network-online.target" ];
+      script = ''
+        timezone="$(${lib.getExe cfg.package} --print-only)"
+        if [[ -n "$timezone" ]]; then
+          echo "Setting timezone to '$timezone'"
+          ${lib.getExe' config.systemd.package "timedatectl"} set-timezone "$timezone"
+        fi
+      '';
+
+      serviceConfig = {
+        Type = "oneshot";
+      };
+    };
+
+    systemd.timers.tzupdate = {
+      enable = cfg.timer.enable;
+      timerConfig = {
+        OnStartupSec = "30s";
+        OnCalendar = cfg.timer.interval;
+        Persistent = true;
+      };
+      wantedBy = [ "timers.target" ];
+    };
+  };
+}