Re: s6-log: Log rotation during shutdown

Aleksy Grabowski <[email protected]> Sat, 28 Feb 2026 08:23:27 +0100
Newsgroups gmane.comp.sysutils.supervision.general
Message-ID <CAETKQWKW9J+f3yi3UMDgRkRDhs=JztHx8nnZ-ci6Y-WR3b-LWA@mail.gmail.com>
> If I understand you correctly, this could be done by inserting `/pat/ { p=
rint | "post-process" }` awk script/`forstdin`/etc. ) in a pipeline after `=
s6-log ... 1`. Either s6-rc's pipeline mechanism, or redirecting s6-log's s=
tdout to a plain ol' named pipe if you don't use the former.

Thanks, that's also a solution, so the pipeline will look like
`producer | s6-log | post-processor`,
so it can be done already with what it there.

>
> Sometimes what I miss in s6-log is having something like `1` but for an a=
rbitrary preopened file descriptor, so lines can be selectively dispatched/=
copied to multiple pipelines, but I haven't needed such functionality yet.
>

It might be useful for example when you use s6 to supervise a
multi-process application
(so s6 is used in this case not as an init system, but rather as a
generic supervisors for a
collection of programs). For example for computational biology when you nee=
d to
process a lot of data it would be cool to be able to create supervised
pipelines with a
more complex topology with splits and merges.

--=20
Alex