Disable kafka metrics by default in v3 (#18828)

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: laurit

instrumentation/kafka/kafka-clients/kafka-clients-0.11/javaagent/build.gradle.kts

@@ -77,6 +77,8 @@ tasks {
     jvmArgs("-Dotel.instrumentation.messaging.experimental.receive-telemetry.enabled=true")
     jvmArgs("-Dotel.semconv-stability.preview=messaging")
     jvmArgs("-Dotel.instrumentation.common.v3-preview=true")
+    // kafka metrics are disabled by default with v3-preview enabled
+    jvmArgs("-Dotel.instrumentation.kafka-clients-metrics.enabled=true")
     systemProperty("metadataConfig", "otel.semconv-stability.opt-in=messaging")
   }
 

instrumentation/kafka/kafka-clients/kafka-clients-0.11/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/kafkaclients/v0_11/metrics/KafkaMetricsInstrumentationModule.java

@@ -9,6 +9,7 @@
 import static java.util.Collections.singletonList;
 
 import com.google.auto.service.AutoService;
+import io.opentelemetry.javaagent.bootstrap.internal.AgentCommonConfig;
 import io.opentelemetry.javaagent.extension.instrumentation.InstrumentationModule;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
 import io.opentelemetry.javaagent.extension.instrumentation.internal.ExperimentalInstrumentationModule;
@@ -37,4 +38,9 @@ public List<TypeInstrumentation> typeInstrumentations() {
     return asList(
         new KafkaMetricsProducerInstrumentation(), new KafkaMetricsConsumerInstrumentation());
   }
+
+  @Override
+  public boolean defaultEnabled() {
+    return super.defaultEnabled() && !AgentCommonConfig.get().isV3Preview();
+  }
 }