Aaron.Akka.Streams.BackpressureMonitor 0.2.0

Aaron.Akka.Streams.BackpressureMonitor

This package provides access to some experimental Akka.NET Streams stages that can be used for monitoring occurrences of backpressure inside your Akka.NET applications.

Installation and Use

To access these stages, install the Aaron.Akka.Streams.BackpressureMonitor NuGet package:

install-package Aaron.Akka.Streams.BackpressureMonitor

Next, use the Aaron.Akka.Streams.Dsl namespace and call the BackpressureAlert extension method on either a Source<T> or a Flow<T> stage:

var source = Source.From(Enumerable.Repeat(0, 10))
    .BackpressureAlert(LogLevel.InfoLevel)
    .RunWith(Sink.Ignore<int>(), Sys.Materializer());

You will see the following logs appear in your stream when backpressure is detected between the downstream consumer and the upstream producer above the BackpressureAlert stage:

[INFO][11/2/2021 7:10:45 PM][Thread 0055][Logic (akka://test)] [BackpressureAlert] Backpressure detected. Measuring duration starting now...
[INFO][11/2/2021 7:10:45 PM][Thread 0055][Logic (akka://test)] [BackpressureAlert] Backpressure relieved. Total backpressure wait time: 00:00:00.0777019

Customizing the BackpressureAlert Logs

If you need to raise backpessure alerts in multiple locations, you can change the name of each BackpressureAlert stage instance via the WithAttributes extension method in Akka.Streams:

var source = Source.From(Enumerable.Repeat(0, 3))
    .BackpressureAlert(LogLevel.InfoLevel).WithAttributes(Attributes.CreateName("MyName"))
    .SelectAsync(1, async i =>
    {
        await Task.Delay(100);
        return i;
    })
    .RunWith(Sink.Ignore<int>(), Sys.Materializer());

The Attributes.CreateName("MyName") call will cause the logs to carry additional context about which alert is firing:

[INFO][11/2/2021 7:10:45 PM][Thread 0045][Logic (akka://test)] [MyName-BackpressureAlert] Backpressure detected. Measuring duration starting now...
[INFO][11/2/2021 7:10:45 PM][Thread 0046][Logic (akka://test)] [MyName-BackpressureAlert] Backpressure relieved. Total backpressure wait time: 00:00:00.0470042

Contributing

See CONTRIBUTING.md for information about building the project from source and contributing changes.