func()

in span.go [88:164]
62 lines of code
15 McCabe index (conditional complexity)

func (tx *Transaction) StartSpanOptions(name, spanType string, opts SpanOptions) *Span {
	if tx == nil {
		return newDroppedSpan()
	}

	if opts.Parent == (TraceContext{}) {
		if opts.parent != nil {
			opts.Parent = opts.parent.TraceContext()
		} else {
			opts.Parent = tx.traceContext
		}
	}
	transactionID := tx.traceContext.Span

	// Lock the parent first to avoid deadlocks in breakdown metrics calculation.
	if opts.parent != nil {
		opts.parent.mu.Lock()
		defer opts.parent.mu.Unlock()
	}

	// Prevent tx from being ended while we're starting a span.
	tx.mu.RLock()
	defer tx.mu.RUnlock()
	if tx.ended() {
		return tx.tracer.StartSpan(name, spanType, transactionID, opts)
	}

	// Calculate the span time relative to the transaction timestamp so
	// that wall-clock adjustments occurring after the transaction start
	// don't affect the span timestamp.
	if opts.Start.IsZero() {
		opts.Start = tx.timestamp.Add(time.Since(tx.timestamp))
	} else {
		opts.Start = tx.timestamp.Add(opts.Start.Sub(tx.timestamp))
	}
	span := tx.tracer.startSpan(name, spanType, transactionID, opts)
	span.tx = tx
	span.parent = opts.parent
	if opts.ExitSpan {
		span.exit = true
	}

	// Guard access to spansCreated, spansDropped, rand, and childrenTimer.
	tx.TransactionData.mu.Lock()
	defer tx.TransactionData.mu.Unlock()

	notRecorded := !span.traceContext.Options.Recorded()
	exceedsMaxSpans := tx.maxSpans >= 0 && tx.spansCreated >= tx.maxSpans
	// Drop span when it is not recorded.
	if span.dropWhen(notRecorded) {
		// nothing to do here since it isn't recorded.
	} else if span.dropWhen(exceedsMaxSpans) {
		tx.spansDropped++
	} else {
		if opts.SpanID.Validate() == nil {
			span.traceContext.Span = opts.SpanID
		} else {
			binary.LittleEndian.PutUint64(span.traceContext.Span[:], tx.rand.Uint64())
		}
		span.stackStackTraceMinDuration = tx.spanStackTraceMinDuration
		span.stackTraceLimit = tx.stackTraceLimit
		span.compressedSpan.options = tx.compressedSpan.options
		span.exitSpanMinDuration = tx.exitSpanMinDuration
		tx.spansCreated++
	}

	if tx.breakdownMetricsEnabled {
		if span.parent != nil {
			if !span.parent.ended() {
				span.parent.childrenTimer.childStarted(span.timestamp)
			}
		} else {
			tx.childrenTimer.childStarted(span.timestamp)
		}
	}
	return span
}