The standard OpenTelemetry Java Agent breaks on Vert.x because it relies on ThreadLocal context propagation, which is incompatible with Vert.x's event-loop model and RxJava's thread-hopping operators. last9/vertx-opentelemetry v2.3.4 is a zero-code javaagent built specifically for Vert.x that solves these problems. For Vert.x 4, it uses the native VertxTracer SPI plus targeted ByteBuddy rewriting; for Vert.x 3, it uses pure ByteBuddy. Key features include: RxJava context propagation via assembly-time hooks, W3C traceparent injection on all outbound calls, Vert.x internal metrics via a Micrometer-to-OTel bridge, automatic log-trace correlation without logback.xml changes, Java 8–21 support, and no Maven dependency required. The agent instruments HTTP server/client, EventBus, SQL, Redis, Kafka, Aerospike, RESTEasy, and AWS SQS. Setup requires only attaching the JAR via -javaagent and setting standard OTel environment variables.
Table of contents
Why the upstream OTel Java Agent breaks on Vert.xVert.x 4: native VertxTracer SPI plus targeted ByteBuddyVert.x 3: pure ByteBuddy bytecode rewritingRxJava context propagation across operatorsW3C traceparent injection on every outbound callJava 8 support — and why it matters for Vert.x 3Vert.x internal metrics via the Micrometer → OTel bridgeLog-trace correlation without touching logback.xmlWhy no Maven dependencyQuick startTroubleshooting common failure modesSend your Vert.x telemetry to Last9ReferencesSort: