startSpan method

@override Span startSpan({ required String parentId, required String spanName, Map<String, String> initialAttributes = const {}, })

Creates a child span within a trace.

The parentId should be a trace ID from startTrace. The spanName should describe the sub-operation (e.g., "query.execution"). Returns a Span object containing span ID.

Thread Safety: The returned Span object is not thread-safe. Do NOT share across isolates.

Implementation

@override
Span startSpan({
  required String parentId,
  required String spanName,
  Map<String, String> initialAttributes = const {},
}) {
  if (spanName.isEmpty) {
    throw ArgumentError('Span name cannot be empty');
  }
  if (parentId.isEmpty) {
    throw ArgumentError('Parent ID cannot be empty');
  }

  final spanId = _generateSpanId();
  final now = DateTime.now().toUtc();

  final span = Span(
    spanId: spanId,
    parentSpanId: parentId,
    traceId: parentId,
    name: spanName,
    startTime: now,
    attributes: initialAttributes,
  );

  _activeSpans[spanId] = span;
  unawaited(_repository.exportSpan(span));
  return span;
}