Alpakka Google Pub Sub


I have the following issue.

I integrate with Google Pub Sub using Alpakka. It works flawlessly when I work with Google Cloud Pub Sub.

However, for the developers machines I want to integrate with Google Pub Sub Emulator. Obviously this is also perfectly supported by Alpakka.
The only issue I have is the really high CPU usage of the local Google Pub Sub Emulator (I run it in the Docker container).
I think this is the result of continuous HTTP pulling from the GooglePubSubSource.
I see in the GooglePubSubSource that it pulls the API constantly if no messages are fetched.
I mean fetch function here:

On my side I wrap the GooglePubSub source in RestartSource. I tried to throttle on my side on this source but it does not help.

To be able to use Alpakka Google Pub Sub at all I need to decrease the CPU usage on developers machines.

Do you have any suggestions?

I would really appreciate it.


For now I resolved it in a away that I implemented a simple PubSub emulator on my side to be used on developers machines so I do not use the Alpakka PubSub with Google PubSub Emulator locally.
However, I’d love to remove my code and use Google PubSub Emulator as intended.