Re: One-shot Shepherd services

["Thompson, David" <dthompson2@worcester.edu>]

On Thu, Apr 18, 2019 at 5:38 PM Ludovic Courtès <ludo@gnu.org> wrote:
>
> Hello Guix!
>
> Today I added support for “one-shot” services in the Shepherd:
>
>   https://git.savannah.gnu.org/cgit/shepherd.git/commit/?id=c121eedfff7a50feddcf08e173d2b0dd807e8804
>
> One-shot services start, perform a short action, and are immediately
> marked as “stopped.”  (systemd has something similar:
> <https://www.freedesktop.org/software/systemd/man/systemd.service.html>.)
>
> The use case is initialization or cleanup actions like the ‘user-homes’
> service.  So far ‘user-homes’ is a regular service whose ‘start’ method
> always fails; as a result, we always see this message:
>
>   Service user-homes could not be started.
>
> From there on, we’ll be able to mark this service as one-shot (patch
> below), and thus shepherd will notice that it successfully started (or
> not) and yet mark it as stopped, which was always the intent.
>
> There are other cases where this could be useful.  For instance, we
> could turn service activation snippets into one-shot services.
>
> Since this augments the Shepherd API, I plan to release it as 0.6.0
> in time for Guix 1.0.  It contains other rather minor changes compared
> to 0.5.0.
>
> Feedback welcome!

A big +1 from me. I use one-shot systemd services all the time.

- Dave