Re: [PATCH] gnu: Add rpc-daemon service

[ludo@gnu.org (Ludovic Courtès)]

John Darrington <jmd@gnu.org> skribis:

> * gnu/services/nfs: New file.
                   ^^
> * gnu/local.mk (GNU_SYSTEM_MODULES): Add it.

For the final patch, please make sure to mention it in guix.texi.

> --- /dev/null
> +++ b/gnu/services/nfs.scm

Missing license.

> @@ -0,0 +1,25 @@
> +(define-module (gnu services nfs)
> +  #:use-module (gnu)
> +  #:use-module (gnu services shepherd)
> +  #:use-module (gnu packages onc-rpc)
> +  #:use-module (guix)
> +  #:export (rpc-service))
> +
> +(define (rpc-shepherd-service config) ; Config is ignored
> +  (list (shepherd-service
> +         (provision '(rpc-daemon))
> +         (requirement '(networking))
> +         (start #~(make-forkexec-constructor
> +                   (list (string-append #$rpcbind "/bin/rpcbind") "-d" "-f")))
> +         (stop #~(make-kill-destructor)))))
> +
> +(define rpc-service-type
> +  (service-type
> +   (name 'rpc)
> +   (extensions (list (service-extension shepherd-root-service-type
> +                                        rpc-shepherd-service)))))

In this case, you can simply write:

  (define rpcbind-service-type
    (shepherd-service-type
     'rpcbind
     (lambda (config)
       (shepherd-service …))))

I think the service should be called “rpcbind”, and not “rpc” (there are
other ONC RPC and NFS daemons, such as mountd and statd, so we need to
use clear names.)

> +(define* (rpc-service config)
> +  "Run the rpc daemon. Config is ignored."
> +  (service rpc-service-type config))

There’s at least one bit of config needed: the ‘rpcbind’ package to
use.  So I would write it as:

  (service rpcbind-service-type rpcbind)

and then honor this argument.

Also, the preferred way now is to expose service-type objects and not
provide procedures like the one above.  So you can omit this procedure
and instead make sure to #:export (rpcbind-service-type).

Could you send an updated patch?

If you’re willing to play a bit, it would be nice to have a system test
that spawns a GuixSD with this service, and then makes sure that, say,
the ‘rpcinfo’ program is able to connect to the daemon.  But that’s
bonus.  :-)

Thanks!

Ludo’.