External API Requests all end up as "Unknown Domain"

[alkanna]

Is there a trick to this ?
I created an instrumented http client that just implements a custom RoundTripper, in which I create a span if needed and enrich its data and set it as an http.client operation.
Is this supposed to be working with the current version of sentry-go ?

This is the RoundTripper :

// RoundTrip implements the http.RoundTripper interface
func (t *SentryTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	if t.BaseTransport == nil {
		t.BaseTransport = httpx.NewClient().Transport
	}

	if len(t.TracePropagationTargets) > 0 {
		requestURL := req.URL.String()
		foundMatch := false
		for _, target := range t.TracePropagationTargets {
			if strings.Contains(requestURL, target) {
				foundMatch = true
				break
			}
		}

		if !foundMatch {
			return t.BaseTransport.RoundTrip(req)
		}
	}

	ctx := req.Context()

	hub := sentry.GetHubFromContext(ctx)
	if hub == nil {
		if currentHub := sentry.CurrentHub(); currentHub != nil {
			hub = currentHub.Clone()
			ctx = sentry.SetHubOnContext(ctx, hub)
			req = req.WithContext(ctx)

			req.Header.Set("baggage", hub.GetBaggage())
			req.Header.Set("sentry-trace", hub.GetTraceparent())
		}

		return t.BaseTransport.RoundTrip(req)
	}

	parentSpan := sentry.SpanFromContext(ctx)
	if parentSpan == nil {
		req.Header.Set("baggage", hub.GetBaggage())
		req.Header.Set("sentry-trace", hub.GetTraceparent())

		return t.BaseTransport.RoundTrip(req)
	}

	cleanRequestURL := req.URL.Redacted()

	spanName := fmt.Sprintf("%s %s", req.Method, cleanRequestURL)

	span := parentSpan.StartChild("http.client", sentry.WithTransactionName(spanName))

	span.Name = spanName

	defer span.Finish()

	span.SetData("http.query", req.URL.Query().Encode())
	span.SetData("http.fragment", req.URL.Fragment)
	span.SetData("http.request.method", req.Method)
	span.SetData("server.address", req.URL.Hostname())
	span.SetData("server.port", req.URL.Port())

	span.SetData("description", fmt.Sprintf("%s %s", req.Method, req.URL.Host))
	span.SetData("url", req.URL.String())
	span.SetData("url.full", req.URL.String())
	span.SetData("url.scheme", req.URL.Scheme)
	span.SetData("http.protocol.name", req.URL.Scheme)
	span.SetData("http.request.body.size", req.ContentLength)
	span.SetData("network.protocol.version", req.Proto)

	AddDetailsToSpan(ctx, span)

	req.Header.Set("baggage", span.ToBaggage())
	req.Header.Set("sentry-trace", span.ToSentryTrace())

	newReq := req.WithContext(span.Context())
	resp, err := t.BaseTransport.RoundTrip(newReq)
	if err != nil {
		span.Status = sentry.SpanStatusInternalError
		span.SetData("error", err.Error())
	}

	if resp != nil {
		span.Status = HTTPtoSpanStatus(resp.StatusCode)
		span.SetData("http.response.status_code", resp.StatusCode)
		span.SetData("http.response_content_length", resp.ContentLength)
	}

	return resp, err
}

[cleptric]

Looks alright to me, I suppose you refer to the Outbound API Requests showing you Unknown Domain? The required span attributes are documented on https://develop.sentry.dev/sdk/telemetry/traces/modules/requests/, but as I said, look good to me.
Could you share a link to your org in case you use sentry.io so we could take a look?