"Daemon not running" exception when avahi-daemon is not running

Severity: minor

My /var/log/guix-daemon.log.* are full of backtraces like these

(and boring messages like SIGPOLL, spurious SIGPOLL, accepted connections

from pid [..], user [...]).

Backtrace:

In ice-9/boot-9.scm:

1752:10 10 (with-exception-handler _ _ #:unwind? _ # _)

In unknown file:

9 (apply-smob/0 #<thunk 7f77d4149f60>)

In ice-9/boot-9.scm:

724:2 8 (call-with-prompt _ _ #<procedure default-prompt-handle…>)

In ice-9/eval.scm:

619:8 7 (_ #(#(#<directory (guile-user) 7f77d4143c80>)))

In guix/ui.scm:

2166:12 6 (run-guix-command _ . _)

In ice-9/boot-9.scm:

1752:10 5 (with-exception-handler _ _ #:unwind? _ # _)

1747:15 4 (with-exception-handler #<procedure 7f77d0deeed0 at ic…> …)

In guix/scripts/discover.scm:

141:8 3 (_)

In guix/avahi.scm:

171:17 2 (avahi-browse-service-thread _ #:types _ #:ignore-local? …)

In unknown file:

1 (make-client #<poll 7f77d0de41c0> () #<procedure client…>)

In ice-9/boot-9.scm:

1685:16 0 (raise-exception _ #:continuable? _)

ice-9/boot-9.scm:1685:16: In procedure raise-exception:

Throw to key `avahi-error' with args `(#<avahi-error-enum Daemon not running> make-client)'.

Some kind of warning message when the daemon is not running makes sense,

but a full backtrace seems unneeded.

Maybe print a line like:

warning: avahi daemon is not running, cannot auto-discover substitute servers!

instead.

Greetings,

Maxime.

Hello Maxime,

This should be fixed with the attached patch.

Thanks,

Mathieu

Hi Mathieu,

Mathieu Othacehe schreef op vr 21-05-2021 om 15:23 [+0200]:

Shouldn't this code print an an error message when err is something

other than error/no-daemon? You can use error->string. Two examples

from (guile-avahi)Error handling:

2.4 Error Handling

==================

Avahi errors are implemented as Scheme exceptions (*note exceptions in

Guile: (guile)Exceptions.). Each time a Avahi function returns an

error, an exception with key 'avahi-error' is raised. The additional

arguments that are thrown include an error code and the name of the

Avahi procedure that raised the exception. The error code is pretty

much like an enumerate value: it is one of the 'error/' variables

exported by the '(avahi)' module (*note Enumerates and Constants::).

Exceptions can be turned into error messages using the 'error->string'

procedure.

The following examples illustrates how Avahi exceptions can be

handled:

(let ((poll (make-simple-poll)))

;;

;; ...

;;

(catch 'avahi-error

(lambda ()

(run-simple-poll (simple-poll poll)))

(lambda (key err function . currently-unused)

(format (current-error-port)

"an Avahi error was raised by `~a': ~a~%"

function (error->string err)))))

Again, error values can be compared using 'eq?':

;; `avahi-error' handler.

(lambda (key err function . currently-unused)

(if (eq? err error/no-daemon)

(format (current-error-port)

"~a: the Avahi daemon is not running~%"

function)))

Otherwise LGTM, but I haven't tested.

Greetings,

Maxime.

Hey,

Fixed with 7003b2db526fc367664f3a7c4bdbe38a7c717da6.

Thanks,

Mathieu