Hello!
Julien Lepiller <jul...@lepiller.eu> skribis:
>>From 5d86226f318a111cc1bdf5a6f044c6f540f51b45 Mon Sep 17 00:00:00 2001
> From: Julien Lepiller <jul...@lepiller.eu>
> Date: Fri, 25 Oct 2019 21:39:21 +0200
> Subject: [PATCH] guix: package: lock profiles when processing them.
>
> * guix/scripts/package.scm (process-actions): Get a per-profile lock to
> prevent concurrent actions on profiles.
> * guix/build/syscalls.scm (with-file-lock/no-wait): New procedure.
> (lock-file): Take a #:wait? key.
Nice! Could you make the syscalls.scm changes a separate patch?
> +(define (call-with-file-lock/no-wait file thunk handler)
> + (let ((port (catch 'system-error
> + (lambda ()
> + (catch 'flock-error
> + (lambda ()
> + (lock-file file #:wait? #f))
> + handler))
> + (lambda args
> + ;; When using the statically-linked Guile in the initrd,
> + ;; 'fcntl-flock' returns ENOSYS unconditionally. Ignore
> + ;; that error since we're typically the only process
> running
> + ;; at this point.
> + (if (or (= ENOSYS (system-error-errno args)) (=
> 'flock-error args))
Please remove tabs. :-)
This is wrong because (1) ‘args’ is always a list, and (2) ‘=’ is
defined for numbers, not for symbols and lists.
I think you actually want to catch two exceptions here: ‘system-error’
and ‘flock-error’. For that, you have to do:
(catch #t
(lambda ()
(lock-file …))
(lambda (key . args)
(match key
('flock-error …)
('system-error
(if (= ENOSYS (system-error-errno (cons key args)))
…))
(_
(apply throw key args)))))
Does that make sense?
> + ;; First, acquire a lock on the profile, to ensure only one guix process
> + ;; is modifying it at a time.
> + (with-file-lock/no-wait
> + (string-append profile ".lock")
Nitpick: I’d move the lock file name on the same line as
‘with-file-lock/no-wait’.
> + (lambda (key . args)
> + (leave (G_ "profile ~a is locked by another guix process.~%")
> + profile))
s/guix// and remove the trailing period.
Could you add a test for that in tests/guix-package.sh?
One way to do it may be to do something like:
echo '(sleep 60) > /…/manifest.scm
guix package -m /…/manifest.scm -p whatever &
pid=$!
if guix install emacs -p whatever; then false; else true; fi
kill $pid
Could you send updated patches?
Thanks!
Ludo’.
