Trying to load Akka instrumentation when using Pekko in Scala 3

[drenizg]

Hi,

I'm moving my Pekko project to Scala 3.3.3, and when I run it, it throws this warning (Only for Scala 3; same code runs fine when compiled with Scala 2.13):

[Attach Listener] WARNING 2024-04-01 08:16:53  Logger : Error trying to load Instrumentation: kamon.instrumentation.akka.instrumentations.akka_25.DispatcherInstrumentation with error: java.lang.ClassNotFoundException: kamon.instrumentation.akka.instrumentations.akka_25.DispatcherInstrumentation 
[Attach Listener] WARNING 2024-04-01 08:16:53  Logger : Error trying to load Instrumentation: kamon.instrumentation.akka.instrumentations.akka_25.remote.RemotingInstrumentation with error: java.lang.ClassNotFoundException: kamon.instrumentation.akka.instrumentations.akka_25.remote.RemotingInstrumentation 
[2024-04-01 08:16:54,498] [INFO] [kamon.status.page.StatusPage] [] [main] - Status Page started on http://0.0.0.0:5266/ MDC: {}
[2024-04-01 08:16:54,753] [INFO] [kamon.prometheus.PrometheusReporter] [] [main] - Started the embedded HTTP server on http://0.0.0.0:9095/metrics MDC: {}
[2024-04-01 08:16:54,801] [INFO] [kamon.Init] [] [main] - 
 _
| |
| | ____ _ _ __ ___   ___  _ __
| |/ / _  |  _ ` _ \ / _ \|  _ \
|   < (_| | | | | | | (_) | | | |
|_|\_\__,_|_| |_| |_|\___/|_| |_|
=====================================
Initializing Kamon Telemetry v2.7.1 / Kanela v1.0.18
 MDC: {}

As a workaround, I successfully disabled those modules in application.conf file:

kanela.modules {
  akka.enabled = false
  akka-remote.enabled = false
}

Any ideas on why is it trying to load Akka instrumentation in a Pekko project with no Akka dependencies?

[Dichotomia]

I confirm this issue.

[Philippus]

I'm guessing you're using the kamon-bundle dependency?
I think this is because the kamon-akka reference.conf has these lines:

      "kamon.instrumentation.akka.instrumentations.akka_25.DispatcherInstrumentation",
      "kamon.instrumentation.akka.instrumentations.akka_26.DispatcherInstrumentation",

and

      "kamon.instrumentation.akka.instrumentations.akka_25.remote.RemotingInstrumentation",
      "kamon.instrumentation.akka.instrumentations.akka_26.remote.RemotingInstrumentation"

but the akka 2.5 instrumentation is not in the kamon-bundle for scala 3 (because there is no akka 2.5 for scala 3).
The reverse is true for scala 2.11, there is no akka 2.6 instrumentation for scala 2.11 (because there is no akka 2.6 for scala 2.11)

Maybe scala 2.11 and akka 2.5 could be dropped.

[mgralle]

In addition to enabling kamon pekko, you need to explicitly remove the kamon-akka modules, e.g.:

kanela.modules {

  akka {
    name = "Akka Instrumentation"
    enabled = no
  }
  akka-remote {
    name = "Akka Remote Instrumentation"
    enabled = no
  }
  akka-remote-sharding {
    name = "Akka Remote Cluster Sharding Monitoring"
    enabled = no
  }
  akka-grpc {
    name = "Akka gRPC Instrumentation"
    enabled = no
  }
  akka-http {
    name = "Akka HTTP Instrumentation"
    enabled = no
  }

It took me a long time to figure this out!

[drenizg]

Right, that's the workaround I mentioned in the issue. However, I'm not sure that should be the way to handle this scenario. If the community think it is, at least that should be clearly stated somewhere in the docs.