While on the subject of conduits and timing, I'm using the following
conduit to add elapsed timing information:
timedConduit :: MonadResource m => forall l o u . Pipe l o o u m (u,
NominalDiffTime)
timedConduit = bracketP getCurrentTime (\_ -> return ()) inner
where inner st = do r <- awaitE
case r of
Right x -> yield x >> inner st
Left r -> deltaTime st >>= \t -> return (r,t)
deltaTime st = liftIO $ flip diffUTCTime st <$> getCurrentTime
I'm aware that this is primarily timing the downstream (and ultimately the
Sink) more than the upstream, and I'm using the bracketP to attempt to
delay the acquisition of the initial time (st) until the first downstream
request for data.
I would appreciate any other insights regarding concerns, issues, or
oddities that I might encounter with the above.
Thanks,
Kevin
On Mon, 04 Feb 2013 02:25:11 -0700, Michael Snoyman <mich...@snoyman.com>
wrote:
I think this is probably the right approach. However, there's something
important to point out: flushing based on timing issues must be handled
*outside* of the conduit functionality, since by design conduit will not
allow you to (for example) run `await` for up to a certain amount of
time.
You'll probably need to do this outside of your conduit chain, in the
initial Source. It might look something like this:
yourSource = do
mx <- timeout somePeriod myAction
yield $ maybe Flush Chunk mx
yourSource
On Sun, Feb 3, 2013 at 5:06 PM, Felipe Almeida Lessa
<felipe.le...@gmail.com
wrote:
I guess you could use the Flush datatype [1] depending on how your
data is generated.
Cheers,
[1]
http://hackage.haskell.org/packages/archive/conduit/0.5.4.1/doc/html/Data-Conduit.html#t:Flush
On Fri, Feb 1, 2013 at 6:28 AM, Simon Marechal <si...@banquise.net>
wrote:
> On 01/02/2013 08:21, Michael Snoyman wrote:
>> So you're saying you want to keep the same grouping that you had
>> originally? Or do you want to batch up a certain number of results?
>> There are lots of ways of approaching this problem, and the types
don't
>> imply nearly enough to determine what you're hoping to achieve here.
>
> Sorry for not being clear. I would like to group them "as much as
> possible", that is up to a certain limit, and also within a "time
> threshold". I believe that the conduit code will be called only when
> something happens in the conduit, so an actual timer would be useless
> (unless I handle this at the source perhaps, and propagate "ticks").
>
> That is why in my first message I talked about stacking things into
the
> list until the conduit has no more input available, or a maximum size
is
> reached, but was not sure this even made sense.
>
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--
Felipe.
--
-KQ
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