Distributed tracing broken between PHP with OTLP and Node.js Sentry SDK

[mnow-cd]

Problem Statement

I'm trying to connect distributed traces across a PHP service and a Node.js service, both reporting to Sentry. The PHP service calls the Node.js service over HTTP.

PHP side uses OpenTelemetry PHP SDK for auto-instrumentation, configured to export via OTLP to Sentry's collector. The OTel PHP SDK propagates trace context using the traceparent header.
Node.js side uses @sentry/node, which sets up OTel internally. The SentryPropagator appears to only read sentry-trace and baggage headers. It does not pick up the incoming traceparent header sent by PHP.
As a result, traces from PHP and Node.js are not connected in Sentry UI.

Solution Brainstorm

I'm not sure whether this should be reported here or in the JavaScript SDK repository. There seem to be two possible fixes:

1. PHP SDK: add a Sentry OTEL propagator that injects sentry-trace and baggage, so downstream Sentry SDKs can pick up the trace context
2. JavaScript SDK: make SentryPropagator also extract trace context from the traceparent header

[linear-code]

PHP-80

[stayallive]

I feel like a good start here would be showing the traceparent headers and how you've configured the JS SDK and see if something is wrong there. It sounds like the PHP side is doing everything it should but it isn't picked up at the other side?

I also don't think any of the code in this repository is used in this code path? Or is the OTEL SDK using this SDK internally? This might be a quick check with JS if they support the baggage header or otherwise with the OTEL folks to emit the sentry-trace header.

[mnow-cd]

I'm using the Sentry PHP SDK with OTLPIntegration. Since the PHP SDK has really no auto-instrumentation, so I'm using the OpenTelemetry PHP SDK for that purpose.
Both PHP and JS Sentry SDKs integrate with OpenTelemetry, but in different and incompatible way:

• PHP: the integration works by configuring the OTel PHP SDK and pointing its OTLP exporter to Sentry's collector. The OTEL SDK then handles all HTTP propagation with traceparent header.
• JS: the SDK integrates more deeply with OTEL by setting up its own span processor and context propagator, which only reads sentry-trace and baggage headers for trace continuation.

Disconnected traces:

PHP Trace:

JS Trace:

Reproduction repo: https://github.com/mnow-cd/sentry-php-js-tracing/tree/main

I've opened this issue here in this repository as an improvement proposal, suggesting an OTEL propagator that emits sentry-trace and baggage headers.

[stayallive]

Ah apologies! I though somehow you were using some other OTEL integration instead of ours 😬

I'll take a look at your repo!