send current span as parent-id for downstream services

[indolent-developer]

Is there way to send current span as parent-id for downstream services.

I see code below but current span id is passed only if span is of type remote. What is way to send current span id to next downsteam service. This is needed so that we can co-relate logs.

if (requireParent === true && currentSpan === undefined) {
span = trace.wrapSpanContext(INVALID_SPAN_CONTEXT);
} else if (requireParent === true && currentSpan?.spanContext().isRemote) {
span = currentSpan;
} else {
span = this.tracer.startSpan(name, options, ctx);
}
this._spanNotEnded.add(span);
return span;
}

https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/http.ts#L641-L650

[dyladan]

Is this for an outgoing request or an incoming request? Have you set either the requireParentforOutgoingSpans or requireParentforIncomingSpans setting?

[indolent-developer]

let me explain my requirement. and let me know how this can be achieved.

I have a code as follows.

1.log('sending out request', requestDetails)
2.makeHttpCall()
3.log('response of out call is',response)

since open telemetry is creating new span id during http call and that span is complete before line 3 is executed, my logs never have new spanId created.

Can some one tell me how to achieve this. I am using pino logger.

[Flarna]

For line 1 it's quite clear that there is no way to get the spanId as the HTTP request has not yet started at all.

You could wrap the three lines into a span created in your code. I don't think that there is any way to get the span created by HTTP client instrumentation (same is true for other client instrumentations like redis,...) so the logged spanId is not that one from the HTTP call it's that one from your span.

[indolent-developer]

hmm that is issue. as my logs no longer have span-id being sent downstream. Could there be some way to override the span creation process. so that I can inject an already created id as span Id that can be used by http-instrumentation ?

e.g passing new spanId as part of requestHeader

[Flarna]

That is not possible. The main idea of a trace is that a span has a unique, random id. if there are more spans with the same id correlation will not work on receiver side.

[Flarna]

The Http instrumentation will set the traceId/SpanId of the span created on the request header. E.g. if you use the W3C tracepropagator the traceparent header is used.