Expose opentelemetry jvm metrics alongside dropwizard metrics [PLEN-67] (#16133)

ledger-service/metrics/src/main/scala/com/digitalasset/metrics/api/reporters/MetricsReporting.scala

@@ -45,6 +45,11 @@ final class MetricsReporting[M](
     for {
       openTelemetry <- OpenTelemetryOwner(registerGlobalOpenTelemetry, extraMetricsReporter)
         .acquire()
+      _ = if (
+        registerGlobalOpenTelemetry
+      ) // if no global lib is registered there is no point in registering them
+        JvmMetricSet
+          .registerObservers() // has to be registered after opentelemetry is created as it uses the global lib
       slf4JReporter <- acquire(newSlf4jReporter(registry))
       _ <- acquire(newJmxReporter(registry))
         .map(_.start())

ledger/sandbox-on-x/src/main/scala/com/daml/ledger/sandbox/MetricsOwner.scala

@@ -33,6 +33,7 @@ case class MetricsOwner(meter: Meter, config: MetricsConfig, name: String)
     }
 
     metricRegistry.registerAll(new JvmMetricSet)
+    JvmMetricSet.registerObservers()
 
     Resource(
       Future(

observability/metrics/BUILD.bazel

@@ -32,6 +32,7 @@ da_scala_library(
         "@maven//:io_dropwizard_metrics_metrics_graphite",
         "@maven//:io_dropwizard_metrics_metrics_jvm",
         "@maven//:io_grpc_grpc_api",
+        "@maven//:io_opentelemetry_instrumentation_opentelemetry_runtime_metrics",
         "@maven//:io_opentelemetry_opentelemetry_api",
         "@maven//:io_opentelemetry_opentelemetry_context",
         "@maven//:io_prometheus_simpleclient",

observability/metrics/src/main/scala/com/daml/metrics/JvmMetricSet.scala

@@ -5,6 +5,7 @@ package com.daml.metrics
 
 import java.util
 
+import io.opentelemetry.instrumentation.runtimemetrics.{GarbageCollector, MemoryPools}
 import com.codahale.metrics.jvm.{
   ClassLoadingGaugeSet,
   GarbageCollectorMetricSet,
@@ -38,4 +39,13 @@ class JvmMetricSet extends MetricSet {
 
 object JvmMetricSet {
   private val Prefix = MetricName("jvm")
+
+  def registerObservers(): Unit = {
+//    BufferPools.registerObservers(openTelemetry)
+//    Classes.registerObservers(openTelemetry)
+//    Cpu.registerObservers(openTelemetry)
+//    Threads.registerObservers(openTelemetry)
+    MemoryPools.registerObservers()
+    GarbageCollector.registerObservers()
+  }
 }