Capture http request headers on spans

[diecgia]

Hi,
Currently, not all http headers are added to spans generated by otel-go. To determine the origin of the request, I want to add the "x-forwarded-for" http header to the spans.

I've seen that in java it is possible to add a property to capture the desired headers, for example, with the OTEL_INSTRUMENTATION_HTTP_CLIENT_CAPTURE_REQUEST_HEADERS env var: https://opentelemetry.io/docs/zero-code/java/agent/instrumentation/http/#capturing-http-request-and-response-headers

Would it be possible to enable these properties for go instrumentation or capture the "x-forwarded-for" header by default on the spans?

Thanks in advance!

[chenguowei]

Yes, I have the same need.

[txabman42]

This is a nice feature and aligned with other auto instrumentation tools like https://github.com/open-telemetry/opentelemetry-java-instrumentation.

Could I get this issue assigned? I can try pushing this.

cc @MrAlias

[txabman42]

After looking through the code, it seems this would be blocked due to the lack of support for swiss maps. >=go1.24 would be affected