The project is supposed to be an example of how to do throttling in an application that uses Akka.

There is a simple processing chain implemented with Akka: There are:

• Sender, who produces messages and sends them to Processor;
• Processor, who does some processing (basically sleeps for 10 ms) and then gives those messages to Receiver
• Receiver who receives messages and prints statistics from time to time.

The problem is that Sender is able to send messages much faster than Processor can process them and sooner or later the whole thing would crash because of out of memory. To solve it there is a Throttler, who receives messages from Receiver and tries to analyse if Sender is sending them faster than Receiver is receiving. In that case Throttler would ask Sender to slow down (and speed up in the opposite case). The whole system should balance itself after a while and process those messages with maxinum speed of the slowest component.

There are metrics that Prometheus could scrape. They are available at port 8001 by default.