Services and log management/monitoring

[rendaw <7e9wc56emjakcm@s.rendaw.me>]

The manual talks about standard services vs shepherd services, but
doesn't really discuss which either are.  My impression is a standard
service is simply a process guix runs on the system (at startup, based
on the graph?), where a shepherd service is a process that is managed
(may be manually started/stopped, automatically restarted, is watched)
by shepherd.

Is that interpretation correct?  My expectation would then be that you
should generally use shepherd services, except when you want very fine
control over how the service is managed.

Do shepherd services automatically get enabled and start when configured
in a guix config?

Okay, just reread everything and I'm quite confused.  It says shepherd
is pid 1, so "shepherd" services are the more fundamental service type?
But the manual says that shepherd services are a particular type of
service, which implies the opposite.  Why would one use "service"
instead of "shepherd-service" (or vice-versa)?

Is it possible to define a service which depends on a shepherd-service?
What about the reverse?

--

On logging - one of the things I like about systemd is that all services
log their stdout/err and there's a standard way to retrieve logs, and
especially query logs from a particular time range/boot.  It also
exposes dbus events when service statuses change - so it's pretty easy
to send a notification if a service dies for instance, maybe with the
logs from the 10m leading up to the issue.

I couldn't find anything about logging and monitoring in the guix manual
(other than statistic collecting agents/dashboards).  In the shepherd
manual all I could find was a note that services send stdout/stderr to
syslog.  Are any of the above possible with this setup?  I've used
syslog systems for years up until systemd, but my impression was that it
was basically a pile of random files you can read manually if you really
must.

Do non-shepherd services also log somewhere?