What happens if the catch-all logger restarts?

From: Guillermo <gdiazhartusch_at_gmail.com>
Date: Sat, 26 Dec 2015 13:11:47 -0300

Hello,

Consider a machine with an s6-linux-init-maker-style setup (s6-svscan
running as process 1, a catch-all logger reading from a FIFO, etc.). I
was wondering if it was possible to make the catch-all logger change
its logging script when it is already running, and thought that this
would require restarting it, e.g. by sending it SIGHUP or SIGTERM (if
s6-log isn't blocking it because of the -p option), and letting the
corresponding s6-supervise process get it up again. But then I asked
myself what would be the consequences if the catch-all logger
restarts, whatever the reason might be.

I guess that for a short window of time, processes that send their
logs to the catch-all logger could potentially receive a SIGPIPE,
right? With a logging chain arrangement, these would mostly be s6-log
(or similar) processes, s6-supervise processes, and s6-svscan. And the
last two block SIGPIPE, according to the documentation. But would the
failing write operations to the logger's FIFO make this a (transient)
situation where logs could be lost?

Thanks,
G.
Received on Sat Dec 26 2015 - 16:11:47 UTC