OtelHttpTracing is not using the same trace as Jetty or Undertow

[froque]

package com.example;

import static io.jooby.Jooby.runApp;

import io.jooby.opentelemetry.OtelHttpTracing;
import io.jooby.opentelemetry.OtelModule;
import io.opentelemetry.api.GlobalOpenTelemetry;

public class App {

	public static void main(final String[] args) {
		runApp(args, app -> {

			app.install(new OtelModule(GlobalOpenTelemetry.get()));
			app.use(new OtelHttpTracing());

			app.get("/foo", ctx -> "Welcome to Jooby!");
		});
	}
}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.example</groupId>
	<artifactId>jooby-otel</artifactId>
	<version>1.0-SNAPSHOT</version>

	<properties>
		<maven.compiler.source>25</maven.compiler.source>
		<maven.compiler.target>25</maven.compiler.target>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-simple</artifactId>
			<version>2.0.18</version>
		</dependency>
		<dependency>
			<groupId>io.jooby</groupId>
			<artifactId>jooby</artifactId>
			<version>4.5.4</version>
		</dependency>
		<dependency>
			<groupId>io.jooby</groupId>
			<artifactId>jooby-jetty</artifactId>
			<version>4.5.4</version>
		</dependency>
		<dependency>
			<groupId>io.jooby</groupId>
			<artifactId>jooby-opentelemetry</artifactId>
			<version>4.5.4</version>
		</dependency>
	</dependencies>
</project>

JVM arguments: -javaagent:opentelemetry-javaagent-2.30.0.jar -Dotel.traces.exporter=console

❯ curl http://localhost:8080/foo
Welcome to Jooby!

Logs:

[otel.javaagent 2026-09-09 18:37:51:648 +0100] [worker-78] INFO io.opentelemetry.exporter.logging.LoggingSpanExporter - 'GET /foo' : 798a732cd9ad93cdb6aeb75bac8edec9 1b83eade46b9a771 SERVER [tracer: io.jooby.opentelemetry:] AttributesMap{data={thread.name=worker-78, http.route=/foo, http.response.status_code=200, thread.id=78, http.request.method=GET, url.path=/foo}, capacity=128, totalAddedValues=6}
[otel.javaagent 2026-09-09 18:37:51:653 +0100] [worker-78] INFO io.opentelemetry.exporter.logging.LoggingSpanExporter - 'GET' : 35205a3f2c1dd9ae541361f119b3c100 174229cc585746ba SERVER [tracer: io.opentelemetry.jetty-12.0:2.30.0-alpha] AttributesMap{data={url.scheme=http, thread.name=worker-78, network.protocol.version=1.1, network.peer.port=46822, user_agent.original=curl/7.81.0, http.response.status_code=200, thread.id=78, http.request.method=GET, url.path=/foo, server.port=8080, network.peer.address=127.0.0.1, server.address=localhost, client.address=127.0.0.1}, capacity=128, totalAddedValues=13}

I was expecting the Jooby span to be an inner span of the Jetty trace 35205a3f2c1dd9ae541361f119b3c100 and not a new trace 798a732cd9ad93cdb6aeb75bac8edec9.

This also happens with jooby-undertow. jooby-netty does not log an extra trace.

Jetty instrumentation can be disabled with OTEL_INSTRUMENTATION_JETTY_ENABLED=false, but I still think it would make sense for Jooby to not create a new trace.