kontainers / micrometer-akka

A library for monitoring Akka that uses Micrometer metrics

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micrometer-akka

This project is a fork of Kamon-Akka. The Kamon team have done a great job and if you are just experimenting with metrics collection, then their tools and documentation are a great starting point. This fork produces metrics in Micrometer format. See also Prometheus-Akka.

Differences from Kamon-Akka:

  • we do not support Kamon TraceContexts, as we currently have no use case for them
  • we support Scala 2.11, Scala 2.12 and Scala 2.13.0-M5
  • we only build with Akka 2.4 but we test the build with Akka 2.5 too (Akka 2.5.19 is the min version needed for Scala 2.13.0-M5)
  • records time in seconds as opposed to nanoseconds (the data is still a double)
"io.kontainers" %% "micrometer-akka" % "0.10.1"

There is a sample project at https://github.com/pjfanning/micrometer-akka-sample

Release Notes

Usage

To enable monitoring, include the appropriate jar as a dependency and include the following Java runtime flag in your Java startup command (aspectjweaver is a transitive dependency of micrometer-akka):

-javaagent:/path/to/aspectjweaver-1.9.2.jar

You will also need to set up the Micrometer Meter Registry.

io.kontainers.micrometer.akka.AkkaMetricRegistry#setRegistry (example)

Configuration

The metrics are configured using application.conf files. There is a default reference.conf that enables only some metrics.

Metrics

Dispatcher

  • differs a little between ForkJoin dispatchers and ThreadPool dispatchers
  • ForkJoin: parallelism, activeThreadCount, runningThreadCount, queuedSubmissionCount, queuedTaskCountGauge stealCount
  • ThreadPool: activeThreadCount, corePoolSize, currentPoolSize, largestPoolSize, maxPoolSize, completedTaskCount, totalTaskCount

Actor System

  • Actor Count
  • Unhandled Message Count
  • Dead Letter Count

Actor

  • One metric per actor instance
  • mailboxSize (current size), processingTime, timeInMailbox, message count, error count

Actor Router

  • One metric per router instance, summed across all routee actors
  • routingTime, timeInMailbox, message count, error count

Actor Group

  • Each actor group has its own include/exclude rules and you can define many groups with individual actors being allowed to be included in many groups - the metrics are summed across all actors in the group
  • actorCount (current active actors), mailboxSize (current size), processingTime, timeInMailbox, message count, error count