Akka stream throttle the transmission bandwidth

[Nicolas Jozwiak]

Hello,

      I’m currently using akka stream 0.11 to process some big files and I want to throttle the transmission bandwidth.

     For example I would like to limit the throughput  to XXX Kb/s. I saw the groupedWithin function but it does not fill my needs.

     Is there a way to do that ? Or is it planned ?

Thanks for your help.

[Endre Varga]

Hi,

There are various ways to implement this. The quick'n'dirty setup is something like (pseudocode):

TickSource -> buffer -> zip.right

toBeThrottled -> zip.left

zip.map(_._2) -> // the throttled output

The above will generate tokens (ticks) periodically, then accumulating them in a buffer. The throttled stream can only progress if there are ticks available in the buffer, otherwise it has to wait for the next token.

This is just a simple example, there are various other (and more efficient) ways to solve it, the most flexible solution would probably be a FlexiMerge, but that is a little bit harder to implement.

-Endre

Thanks for your help.

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[Nicolas Jozwiak]

Hi,

   Do you know if some documentations or examples exists with FlexiMerge ?

Thanks for your response ! 

[Endre Varga]

Hi,

On Wed, Nov 26, 2014 at 2:25 PM, Nicolas Jozwiak <n.jo...@gmail.com> wrote:

Hi,

   Do you know if some documentations or examples exists with FlexiMerge ?

Currently there are only API docs: http://doc.akka.io/api/akka-stream-and-http-experimental/0.11/#akka.stream.javadsl.FlexiMerge

You can look at the test cases to have a feel of how they are used: https://github.com/akka/akka/blob/release-2.3-dev/akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphFlexiMergeSpec.scala

-Endre

[Nicolas Jozwiak]

Hi,

    I will look at the test code.

Thank you.

[Patrik Nordwall]

Future questions about how to use Akka are welcome at akka-user.

akka-dev is intended for discussion of how to develop Akka itself.

Thanks,

Patrik

Patrik Nordwall
Typesafe -  Reactive apps on the JVM
Twitter: @patriknw