4.x: Metrics: WARNING Unexpected discovery of unknown previously-created meter

[barchetta]

Environment Details

• Helidon Version: 4.0.5
• Helidon SE
• JDK version: java 21.0.2 2024-01-16 LTS

---

Problem Description

Metric example reports the following when run:

2024.02.14 16:52:09 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@8c71f846
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@763f8121
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@8cb1f1f9
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@c923efe7
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@9ef2fc51
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@c47c45b3
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@5007121b
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@d3477c9d
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeFunctionCounter@f0493908
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeFunctionCounter@6b6e6c61
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@59417b18
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeGauge@fe8717a
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeFunctionCounter@57613ee1
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeFunctionCounter@cbd5f394
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeFunctionCounter@6df5c008
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeFunctionCounter@e26a74bb
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeFunctionCounter@91b6f2f0
2024.02.14 16:52:10 WARNING io.helidon.metrics.providers.micrometer.MMeterRegistry Thread[#1,main,5,main]: Unexpected discovery of unknown previously-created meter; creating wrapper for io.micrometer.core.instrument.composite.CompositeFunctionCounter@62ba7a3

Steps to reproduce

git checkout tags/4.0.5
cd examples/metrics/http-status-count-se
mvn clean install
java -jar target/http-status-count-se.jar

I have also seen this outside of the example if I create a Meter in the global registry:

 private final Counter mycounter = Metrics.globalRegistry().getOrCreate(Counter.builder("mycounter"));

[barchetta]

custom-se.zip

Small reproducer. It appears as though this dependency is required to reproduce the issue:

        <dependency>
            <groupId>io.helidon.metrics</groupId>
            <artifactId>helidon-metrics-system-meters</artifactId>
            <scope>runtime</scope>
        </dependency

[tjquinno]

Thanks. My local changes resolve this in both the http-status-count-se example and the reproducer.