bug#59515: nginx: Fails to start on boot while upstream service is not yet running

["Ludovic Courtès" <ludo@gnu.org>]

Jonathan Brielmaier <jonathan.brielmaier@web.de> skribis:

> I added `(shepherd-requirement '(radicale))` to my nginx-configuration.
> Sadly the issue is not fixed, the situation is the same as before.
>
> I assume that radicale takes a fracture of a second to start. And nginx
> starts faster up. See this small experiment:

That looks like a bug in the radicale service: there’s no
synchronization upon startup:

--8<---------------cut here---------------start------------->8---
     (list (shepherd-service
            (provision '(radicale))
            (documentation "Run the radicale daemon.")
            (requirement '(networking))
            (start #~(make-forkexec-constructor
                      (list #$(file-append package "/bin/radicale")
                        "-C" #$config-file)
                      #:user "radicale"
                      #:group "radicale"))
            (stop #~(make-kill-destructor))))
--8<---------------cut here---------------end--------------->8---

It should wait for a PID file or be started as a systemd or inetd
service.  That way, we’d be sure that shepherd considers it started once
it’s really listening for input.  A quick grep in the source suggests it
creates a PID file somewhere.

HTH!

Ludo’.