How do I set up distributed tracing (OpenTelemetry) across microservices?

Short answer: don’t invent a custom scheme; standardize on W3C Trace Context (traceparent/tracestate) so PHP and Go interoperate without friction.

Your real problem is “where’s the 800ms” — and to see it the trace has to travel across services and queues without breaking. Here’s the mechanism:

1. Make W3C Trace Context the standard. Start the root span at the gateway; every service extracts context from the incoming HTTP header and injects it into outgoing calls. Because it’s a standard header, Laravel and Go read the same traceparent in common — don’t invent your own trace_id header.
2. Carry the same traceparent through queues. When you publish a message, add traceparent as a message header/attribute and re-extract it in the worker. This is exactly the piece teams forget; skip it and async hops show up as orphan traces in the APM and the chain breaks.
3. Put the OTel SDK in each service, ship via OTLP. Service → OTLP → a Collector → Jaeger/Tempo. A Collector in between decouples export from the app and makes swapping backends easy.
4. Choose sampling smartly. Use parent-based so all spans of a trace share the same fate; add tail sampling on top so you definitely keep the 800ms outliers. With head-only sampling you drop the very slow trace you wanted to see.
5. Don’t hand-roll trace_id. Don’t write your own header read/write code; the SDK’s context propagation already carries it. Do it by hand and you’ll forget it somewhere and the trace snaps there.

Bottom line: I’d set up W3C Trace Context + the OTel SDK + a Collector + Tempo/Jaeger, leave propagation to the SDK, and never skip putting traceparent into the message header on the queue hop. I explain the architectural reasoning for why I build it this way on sade.dev; you’ll find the detail of the Go-side HTTP mechanics in the hub post. Only an unbroken trace shows you the 800ms.