[bug#31911] services: Add prometheus-node-exporter-service-type.

["Clément Lassieur" <clement@lassieur.org>]

Hi Gábor,

Gábor Boskovits <boskovits@gmail.com> writes:

> Pushed to master as a33652ee336ae9a5d2ab5fd54bf2397caec42a0e.

> +          (test-assert "prometheus-node-exporter running"
> +            (marionette-eval
> +             '(begin
> +                (use-modules (gnu services herd))
> +                (match (start-service 'prometheus-node-exporter)
> +                  (#f #f)
> +                  (('service response-parts ...)
> +                   (match (assq-ref response-parts 'running)
> +                     ((pid) (number? pid))))))
> +             marionette))

The PID check is useless because START-SERVICE will return #f if the
service fails to start.  Instead, I'd use:

          (test-assert "prometheus-node-exporter running"
            (marionette-eval
             '(begin
                (use-modules (gnu services herd))
                (start-service 'prometheus-node-exporter))
             marionette))

This would also make the test more robust to service changes (e.g. it
would still work if MAKE-FORKEXEC-CONSTRUCTOR is removed).

Clément