feat(event-bus): restore event-bus plugin with W3C OTel traceparent propagation

[sumitjha-arch]

Summary

• Restores the event-bus plugin (removed in 2.14.0) as WMS production services depend on fp-plugins@2.12.0 which includes it
• Fixes broken distributed traces across the GCP Pub/Sub async boundary — traceparent was never injected on publish or extracted on consume, causing every incoming Pub/Sub message to start a disconnected root span in Jaeger
• Fixes TypeScript 6.0 compilation errors in azure-servicebus.ts, rabbitmq.ts, and commons.ts introduced by the TS 6.0 upgrade that removed this code

Root cause

publishToPubSub() set attrs = { event } and called topic.publishMessage() with no traceparent attribute. The push handler at /gcp-pubsub/process-message read the message but never called propagation.extract(). Result: every Pub/Sub-triggered handler was a new root span — invisible in Jaeger alongside the originating HTTP request.

What changed

src/event-bus/gcp-pubsub.ts

On publish:

// NEW — inject active span context into Pub/Sub message attributes
if (otel) {
  otel.propagation.inject(otel.context.active(), attrs);
}
topic.publishMessage({ json: { event, payload }, attributes: attrs });

On consume (push handler):

// NEW — extract parent context, start CONSUMER span, run handlers in context.with()
const parentCtx = otel.propagation.extract(otel.context.active(), attrs);
const span = tracer.startSpan(`pubsub.consume.${eventMsg.event}`, { kind: otel.SpanKind.CONSUMER }, parentCtx);
const handlerCtx = otel.trace.setSpan(parentCtx, span);
await otel.context.with(handlerCtx, runHandlers);

src/event-bus/event-consumer/gcp-pubsub.ts

Pull consumer now extracts traceparent from message attributes, starts a pubsub.pull.process CONSUMER span, and re-injects the context as HTTP headers into the internal instance.inject() call so the push handler receives the correct trace context.

OTel API loading

Both files use a lazy getOtelApi() helper — tries @opentelemetry/api via NODE_PATH first (Kubernetes OTel operator), falls back to the pnpm content-addressed path, returns null (no error) if unavailable. Safe to deploy without OTel.

Test evidence

Verified in a kind cluster with a GCP Pub/Sub emulator, comparing side-by-side deployments:

Scenario	message.attributes.traceparent	Jaeger result
No fix	ABSENT	3 disconnected trace trees
With fix	00-89adb2d60dd4fd1e8c2d1bafd228e468-9f94e3df4a135bc3-01	Single trace tree, HTTP → outbox → consumer

The traceID is preserved end-to-end from the original HTTP request through the pg-boss outbox worker through the Pub/Sub consumer handler.

Test plan

• pnpm run build passes (TypeScript compilation clean)
• pnpm test passes (unit tests)
• Deploy to a staging WMS environment, trigger an event, confirm single trace in SigNoz/Jaeger with pubsub.consume.<event> span as child of the originating HTTP span

🤖 Generated with Claude Code

[sumitjha-arch]

Closing — will be handled differently