Maven extensions keeps logging `WARNING: Failed to export metrics` when disabled about opentelemetry-java-contrib

[XN137]

always seen afaict

[cyrille-leclerc]

Can you please indicate which version of Maven you are your using?

[XN137]

we are using 3.9.6 via maven wrapper

[cyrille-leclerc]

Thanks, is it a regression or a problem you have always seen?

[cyrille-leclerc]

Problem was introduced when the OTel Java SDK AutoConfigure changed the default of otel.metrics.exporter from none to otlp.

Problem is here:

opentelemetry-java-contrib/maven-extension/src/main/java/io/opentelemetry/maven/OpenTelemetrySdkService.java

Lines 85 to 91 in 4280422

	// Change default of "otel.traces.exporter" from "otlp" to "none"
	// The impacts are
	// * If no otel exporter settings are passed, then the Maven extension will not export
	// rather than exporting on OTLP GRPC to http://localhost:4317
	// * If OTEL_EXPORTER_OTLP_ENDPOINT is defined but OTEL_TRACES_EXPORTER is not, then don't
	// export
	Map<String, String> properties = Collections.singletonMap("otel.traces.exporter", "none");

I'll propose a fix asap

[cyrille-leclerc]

@XN137 the OTel Maven extension doesn't produce OpnTelemetry metrics or logs. Could you have used the OTel Maven extension in conjunction with adding the Otel Java Agent through the Maven JVM startup parameters?

Note that a fix is in progress on:

• #1276

[XN137]

@cyrille-leclerc i dont think our build uses any other plugin or extension directly related to otel, so the answer is most likely no.

our product code generally uses otel and one of the product jars gets loaded through through exec-maven-plugin as part of the build, but not intentionally doing anything with otel.

wondering: were you not able to reproduce these warnings or why does it matter what our build does in terms of merging your changes?

thanks!

[cyrille-leclerc]

Sorry for the delay.

I cannot reproduce on my SpringBoot test app but #1276 is definitely a change we have to roll out and it's likely to fix your problem.

Can you please enable an otel collector and list the metrics that are generated to help us understand the cause of the problem?

[XN137]

can you provide details on how to get that list?

[cyrille-leclerc]

A solution to list the produced OTel metrics is to connect the Maven build to a local OTel Collector that uses a metrics pipeline with a "Prometheus Exporter".

After your Maven build has run, you can list all the produced metrics looking at the Prometheus page http://localhost:8889/metrics

  prometheus:
    endpoint: 127.0.0.1:8889
    resource_to_telemetry_conversion:
      enabled: true

[XN137]

after upgrading opentelemetry-maven-extension to 1.36.0-alpha in our .mvn/extensions.xml local builds seem to no longer log the mentioned warnings

@cyrille-leclerc thanks for the update, we can most likely close this ticket now?

[cyrille-leclerc]

Thanks I'm closing