system.activationScripts with dependencies from pkgs

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1

I’m looking for a way to run a maintained and initialization script whenever the user rebuilds their system (or reboots, or activates their env, etc).

However, my script requires access to rsync in order to work.

What can I use to accomplish this in activationScripts?

Can I:

  1. require a package dependency via my config?
  2. Turn my shell script into a shellScriptApplication, and call that script from activationScripts?
  3. Some secret third thing
2

Umm… just use string antiquotes to include the full store path of the binary in the script?

3

More specifically, use string interpolation, as the nix manual explains:

''
  echo blah
  ${lib.getExe pkgs.whatever} --flag1 --flag2
  ${lib.getExe' pkgs.whateverWithMultipleBinaries "binary"} --flag3 arg4
''

rsync only has one binary which matches the pname, so getExe will suffice here.

4

Please do not use activation scripts for this. Just make a systemd service. Happening again on rebuild is what sysinit-reactivation.target is for. Activation scripts should have been deprecated long ago.

5 Likes
5

That also lets you use path for convenient binary access. A more fully worked example:

{ pkgs, ... }: {
  systemd.services.my-init-script = {
    wantedBy = [
      "sysinit-reactivation.target"
    ];

    path = [
      pkgs.whatever
    ];

    script = ''
      whatever do something --now
    '';

    serviceConfig.Type = "oneshot";
  };
}
1 Like
6

I’m going to try this– thanks for the tip about that target.