4.x Global tracer not set as part of Helidon MP start-up with OpenTelemetry

[tjquinno]

Environment Details

• Helidon Version: 4.x
• Helidon SE or Helidon MP MP
• JDK version:
• OS:
• Docker version (if applicable):

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Problem Description

Helidon's OpenTelemetry CDI producer for tracing items (such as tracer, etc.) does not assign the Helidon global tracer soon enough.

Although injection points for the Tracer contain the correct, fully-configured tracer, an access to Tracer.global() before CDI has to produce a tracing element incorrectly returns the default (no-op) tracer.

Steps to reproduce

Add the following test to the helidon-microprofile-telemetry component:

@HelidonTest
@AddConfig(key = "otel.sdk.disabled", value = "false")
class TestTracerAtStartup {

    @Test
    void checkForFullFeaturedTracerAtStartup() {
        assertThat("Global tracer from start-up extension",
                   TestExtension.globalTracerAtStartup.unwrap(io.opentelemetry.api.trace.Tracer.class).getClass().getName(),
                   not(containsString("Default")));
    }
}

The test fails because, although the server has completed its start-up work, CDI has not created the Helidon producer app-scoped bean and that code assigns global tracer.