generateTracingContext function

TracingContext generateTracingContext(AtatusSdk sdk, AtatusRum rum, { TracingId? parentSpanId, })

Generate a tracing context.

While a manual trace is active (AtatusRum.startTrace) the context joins that trace. The first request made in the trace becomes its root span, and every later request is a direct child of that first request, so they are siblings rather than each nesting inside the request before it. Outside a manual trace each call starts its own trace.

Pass parentSpanId when the request is a child of a span created elsewhere (e.g. a manually started Flutter span); it takes precedence over the active trace's root. The parent span id is surfaced both in distributed-tracing headers (B3 multi X-B3-ParentSpanId, W3C tracestate) and as the _atatus.parent_span_id resource attribute.

Implementation

// ATCHG - Change class name from DDSdk to AtatusSdk
TracingContext generateTracingContext(
  AtatusSdk sdk,
  AtatusRum rum, {
  TracingId? parentSpanId,
}) {
  final activeTrace = rum.activeTraceContext;

  final traceId =
      activeTrace != null ? activeTrace.traceId : TracingId.traceId();
  final spanId = TracingId.spanId();

  // Inside a manual trace (`startTrace`) the first request is the root span
  // and every later one is its child. Both are reported RUM resources, so no
  // request points at a parent that never arrives (a "missing span"). The
  // trace's own context is only a carrier for the trace id and sampling
  // decision - its span id is never reported, so it is never a parent. The
  // active context is deliberately left untouched here: replacing it with
  // each request's context is what used to nest requests one inside the next.
  var effectiveParentSpanId = parentSpanId;
  if (activeTrace != null) {
    final rootSpanId = rum.traceRootSpanId;
    if (rootSpanId == null) {
      rum.traceRootSpanId = spanId;
    } else {
      effectiveParentSpanId ??= rootSpanId;
    }
  }

  final context = sdk.platform.getContext();
  bool sampled = activeTrace != null
      ? activeTrace.sampled
      : rum.shouldSampleTrace(context?.sessionId, traceId);

  return TracingContext(
    traceId,
    spanId,
    effectiveParentSpanId,
    context?.sessionId,
    context?.userId,
    context?.accountId,
    sampled,
  );
}