bug#36838: mcron leaves zombies around

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi Leo,

Leo Prikler <leo.prikler@student.tugraz.at> writes:

> Hi Maxim,
>
> I still have a defunct mcron flying around with a fairly standard Guix
> configuration.  The only service running through mcron seems to be
> rottlog-service-type.

If you have the energy/bandwidth, would you mind trying this patch here:
https://lists.gnu.org/archive/html/bug-mcron/2021-08/msg00008.html; it
may have positive side-effects in that regard, I believe.

I've modified the mcron package to use a local checkout in my system
config like so:

--8<---------------cut here---------------start------------->8---
@@ -2,7 +2,14 @@
 ;;; RAID-1c3 storage bay.
 (use-modules (gnu)
              (guix modules)
-             (srfi srfi-1))
+             (srfi srfi-1)
+             ;; for mcron experiment
+             (gnu packages autotools)
+             (gnu packages guile-xyz)
+             (gnu packages man)
+             (gnu packages texinfo)
+             (guix git)
+             (guix packages))
 
 (use-service-modules admin desktop docker linux mail mcron networking nfs nix
                      spice ssh sysctl telephony virtualization vpn xorg)
@@ -196,6 +203,15 @@
         (pam-limits-entry "@realtime" 'both 'memlock 'unlimited)))
       (service mcron-service-type
                (mcron-configuration
+                (mcron (package/inherit mcron
+                         (source (git-checkout
+                                  (url "file:///home/maxim/src/mcron")))
+                         (native-inputs (append
+                                         `(("autoconf" ,autoconf)
+                                           ("automake" ,automake)
+                                           ("help2man" ,help2man)
+                                           ("texinfo" ,texinfo))
+                                         (package-native-inputs mcron)))))
                 (jobs (list duckdns-job
                             backup-home-job
--8<---------------cut here---------------end--------------->8---

The output is now annotated as:

--8<---------------cut here---------------start------------->8---
2021-08-25T00:01:34 /gnu/store/xcngj8vg5j8g54r3aqm71vbgsgrsjl31-rottlog-0.72.2/sbin/rottlog: mail: Cannot open mailer: No such file or directory
2021-08-25T00:01:34 /gnu/store/xcngj8vg5j8g54r3aqm71vbgsgrsjl31-rottlog-0.72.2/sbin/rottlog: mail: cannot send message: No such file or directory
2021-08-25T00:01:34 /gnu/store/xcngj8vg5j8g54r3aqm71vbgsgrsjl31-rottlog-0.72.2/sbin/rottlog: mail: Cannot open mailer: No such file or directory
2021-08-25T00:01:34 /gnu/store/xcngj8vg5j8g54r3aqm71vbgsgrsjl31-rottlog-0.72.2/sbin/rottlog: mail: cannot send message: No such file or directory
2021-08-25T00:01:34 /gnu/store/xcngj8vg5j8g54r3aqm71vbgsgrsjl31-rottlog-0.72.2/sbin/rottlog: mail: Cannot open mailer: No such file or directory
2021-08-25T00:01:34 /gnu/store/xcngj8vg5j8g54r3aqm71vbgsgrsjl31-rottlog-0.72.2/sbin/rottlog: mail: cannot send message: No such file or directory
2021-08-25T00:01:34 /gnu/store/xcngj8vg5j8g54r3aqm71vbgsgrsjl31-rottlog-0.72.2/sbin/rottlog: completed in 93.625s
2021-08-25T00:05:00 duckdns-update: running...
2021-08-25T00:05:01 duckdns-update: completed in 0.519s
--8<---------------cut here---------------end--------------->8---

And I don't have any mcron zombie process lying around, unless I'm
reading the ps output wrong.

Thanks,

Maxim