Does withSimpleStdOutLogger ever flush?

[linearray]

I'm using a custom logger that is based on (withSimple)stdoutLogger:

log/log-base/src/Log/Backend/StandardOutput.hs

Line 36 in f93584d

stdoutLogger :: IO Logger

I debugged an issue today concerning log messages appearing 15 minutes in the log after the message was actually emitted. I traced it back to GHC using block-buffering for stdout, if the FD is not associated with a TTY, which is the case for my service since it is managed by systemd. Now I wonder: Does the provided StandardOutput logger ever flush, because after looking at the code I don't think so.

Is this considered out of scope and applications are expected to set the correct buffering on stdout themselves (or call hFlush in the logging action)?

[jonathanjouty]

IIRC it is out of scope and must be set on stdout
I'll let @23Skidoo give a definitive answer when he's back from ICFP :)

[23Skidoo]

Given that we provide our own BulkStdoutLogger, I think we should make stdout loggers flush on each write (bulk write in the case of the bulk logger), plus make them flush on exit. I'll write a patch.

[23Skidoo]

Released log-base-0.7.3.0 on Hackage.