filterfish/logging-effect-test

Repo to set the logging effect library

Test repo to work out why the logging-effect is not doing what I think it is. See Ticket #14.

#Findings

There isn't a promlem with the logging-effect library!

It looks like there is an interaction between BatchingOptions and the fact that stdout is, by default, buffered.

With Buffering

NOTE: I'm using the following batch options:

BatchingOptions {flushMaxDelay = 0, flushMaxQueueSize = 1, blockWhenFull = True}

The code will log a message every second but will only output those messages when stdout's buffer is full. If I set the buffering to NoBuffering or LineBuffering a log message is output every message. This is also true if I set stdout's buffer size to exactly the length of the log message. If I set the log message to twice the size of the log message then messages are output in pairs. If I set stout's buffer to three times the size of the log message then messages are output in groups of three and so on.

I think this is a pretty clear demonstration of what's going on.

I think the following quote sums it up quite well:

... For most implementations, physical files will normally be block-buffered and terminals will normally be line-buffered.