Mesmer (version 0.8.0) - How to collect Default-JVM-Metrics from ZIO 2.0.0 Apps

[ghost]

This Mesmer Discussion is related to this "Mesmer Research Task (#424)".

I will be answering the following questions from #424:

1. "Figure out how to turn on Jvm metrics collection."
2. "If it works with few configuration needed, explain how to do it in mesmer documentation so that users can see those thanks to Mesmer as well"

1) Figure out how to turn on Jvm metrics collection

• In the User's ZIO 2.0 App, make sure that this ZIO App has the following two lines added in the code: https://github.com/zio/zio-metrics-connectors/blob/zio/series2.x/core/jvm/src/test/scala/zio/metrics/connectors/SampleApp.scala#L69-L70

• Both Runtime.enableRuntimeMetrics are DefaultJvmMetrics.live.unit needed, in order to enable the ZIO internal metrics and the default JVM metricsConfig.

2. "If it works with few configuration needed, explain how to do it in mesmer documentation so that users can see those thanks to Mesmer as well"

• As of now, Mesmer is not able to collect ZIO DefaultJvmMetrics.
• However, ZIO 2.0 Devs are currently working on a feature regarding "collecting JVM Metrics inside a ZIO Application": https://zio.dev/reference/metrics/jvm/#collecting-metrics
• I will keep an eye for updates to this ZIO JVM Metrics documentation (https://zio.dev/reference/metrics/jvm/), and will update this discussion as needed.

[ghost]

CC @lgajowy and @worekleszczy

[lgajowy]

As of now, Mesmer is not able to collect ZIO DefaultJvmMetrics.

@ronaldSC-2022 we recently merged zio counters and gauges collection. If you run mesmer from main branch with the forkenstein app (that has the default jvm metrics enabled) doesn't it collect the counters and gauges?

[ghost]

@lgajowy, you are correct:

If we run Mesmer from the main branch with the forkenstein app (that has this DefaultJvmMetrics.live.unit commit: lgajowy/forkenstein@ce55749)... then Mesmer will collect the counters and gauges.

I think I mis-spoke / I wrote my discussion incorrectly:

• "As of now, Mesmer is not able to collect ZIO DefaultJvmMetrics" should be re-written as "Mesmer is not able to collect ZIO DefaultJvmMetrics if the User's ZIO App does not have the default jvm metrics enabled"

Everything else, I agree with you. 😄

PS, if needed, let's discuss more in our Mesmer meeting today, Lukasz.

[lgajowy]

I confirm that we get them forwarded to otel:

Great stuff :)