How to configure smartd and send notifications?

[Tristan Kohl via <help-guix@gnu.org>]

Hello Guix gurus,

I have a hard time wrapping my head around how to configure smartd (1) and send notifications via ntfy.sh (2).

1. Configuration of smartd
I could not find anything in the admin module in the Guix repository on how to configure smartd (i.e. smartd-configuration) - there I found only smartmontools build procedure.

When checking /var/log/messages I could see that smartd defaults to some configuration file in the store rather than the default /etc/smartd.conf. So I tried to write my own:

(define smartd-send-ntfy
	(plain-file "/usr/local/sbin/send-ntfy" "#!/bin/sh\ncurl ntfy.sh/<my-topic> -d 'curl -Ls -H "Title: $SMARTD_SUBJECT" -d "$SMARTD_FAILTYPE Device: $SMARTD_DEVICE Time: $SMARTD_TFIRST Message: $SMARTD_FULLMESSAGE"'))

(define smartd-config-file
	(plain-file "smartd.conf" "DEVICESCAN -a -s (S/../.././03|L/../01/./04) -m <nomailer> -M exec /usr/local/sbin/send-ntfy -M test"))

(services
	(append
		(list
			...
			(simple-service
				'smartd-service
				shepherd-root-service-type
				(list
					(shepherd-service
						(documentation "Monitor disks for failure.")
						(provision '(smartd))
						(requirement '(udev user-processes))
						(start
							#~(make-forkexec-constructor
								(list "/run/current-system/profile/sbin/smartd" "--no-fork" "-c" smartd-config-file)))
						(stop #~(make-kill-destructor))))))
		%base-services))


This results in a warning "possibly unbound variable `smartd-config-file". Tried to understand G-expressions and put #$smartd-config-file in there but I am already overwhelmed with (un)quote so I guess I am missing the point here. Also how do I get the store path from smartd-notify-send into smartd-config-file because my naive approach putting the path into plain-file name argument does not work.

2. Notifications
Also I have a bunch of mcron jobs which I also would like to use ntfy.sh to send messages to me. How do I append a string to the srcub job passing a message to msg? Is this even the right way?

(define (notify msg)
	(string-append "curl ntfy.sh/sTu0vFzNZqfMSLJiRAxuTHEUHy8BYWW6 -d '" msg "'"))

(define monthly-srub-job
	#~(job
		"0 3 1 * *"
		"btrfs scrub start -dB /pool" ))

Sorry for these beginner questions, I just started diverting from copy-pasting config parts from others.

Thank you!