[Shepherd] Should 'herd status' block for a long-running timer?

[Shepherd] Should 'herd status' block for a long-running timer?

[Felix Lechner via Development of GNU Guix and the GNU System distribution.]

Hi,

Are 'herd status' and 'herd status NAME' supposed to block on
long-running timers like this one?  [1]  Thanks!

Kind regards
Felix

[1] https://codeberg.org/lechner/system-config/src/commit/313b333d1e87477a3c1455e6a73485d9e348b7e2/host/wallace-server/operating-system.scm#L565-L665

Re: [Shepherd] Should 'herd status' block for a long-running timer?

[Ludovic Courtès]

Hi,

Felix Lechner via "Development of GNU Guix and the GNU System
distribution." <guix-devel@gnu.org> skribis:

> Are 'herd status' and 'herd status NAME' supposed to block on
> long-running timers like this one?  [1]  Thanks!

In this case the timer is using a Scheme procedure, not a <command>
record.  Procedures must be written in a non-blocking/suspendable
fashion, as noted in the manual.

That said, I don’t immediately see what could block in your timer: it
uses ‘system*’ to spawn processes, which is suspendable inside shepherd.
Would be nice if you explain when it’s blocking and/or use ‘strace’ to
see what’s going on while it’s blocking.

That said, this timer is a bit long; I’d suggest going for something
simpler and/or deferring to a <command> that does the heavy lifting.

HTH,
Ludo’.