Missing http.target in HTTP Outgoing spans to sampling using ParentBasedSampler

[habmic]

Hi,
We are trying to have a sample rate on a specific use case in a customer app. Service is having an interval that every X seconds send an API call to another service. This means the root span is an HTTP Outgoing, we would like to apply the sampling rule on a specific http.url (/api/v1/test for example).

ParentBasedSampler is the sampler we use, and it decides to sample are not when a span is starting i.e in startSpan function. This means we must have access to http.url orhttp.target (otherwise we won't know if it should be sampled), however, those are being added to the span only once it ends even though the is purely request data and not related to the response.

opentelemetry-js/packages/opentelemetry-instrumentation-http/src/utils.ts

Line 354 in 8e5c8a0

[SemanticAttributes.HTTP_TARGET]: requestOptions.path || '/',

here you can see the outgoing data being set once the span closes and the data it uses is request data.

Do you know if this is the expected behavior?

• This only affects the JavaScript OpenTelemetry library