jaegertracing/jaeger · error

failed to get trace: %w

Error message

failed to get trace: %w

What it means

In the get_span_details handler, the aggregated trace iterator from the query service can return a per-trace error. For a singular trace lookup (specific trace_id), such an error is fatal and is wrapped with "failed to get trace". It represents a trace-retrieval failure at the storage layer (or a not-found surfaced as an error), not malformed input.

Source

Thrown at cmd/jaeger/internal/extension/jaegerquery/internal/mcptools/internal/handlers/get_span_details.go:81

	// Create span ID set for efficient lookup
	spanIDSet := make(map[string]struct{}, len(canonicalSpanIDs))
	for _, spanID := range canonicalSpanIDs {
		spanIDSet[spanID] = struct{}{}
	}

	tracesIter := h.queryService.GetTraces(ctx, params)

	// Wrap with AggregateTraces to ensure each ptrace.Traces contains a complete trace
	aggregatedIter := jptrace.AggregateTraces(tracesIter)

	// Collect spans matching the requested span IDs
	var spanDetails []types.SpanDetail
	traceFound := false

	for trace, err := range aggregatedIter {
		if err != nil {
			// For singular lookups, return error directly
			return nil, types.GetSpanDetailsOutput{}, fmt.Errorf("failed to get trace: %w", err)
		}

		traceFound = true

		// Iterate through all spans in the trace
		for pos, span := range jptrace.SpanIter(trace) {
			spanIDStr := span.SpanID().String()

			// Check if this span ID is in the requested set
			if _, found := spanIDSet[spanIDStr]; found {
				detail := buildSpanDetail(pos, span)
				spanDetails = append(spanDetails, detail)

				// Remove from set to track which spans we've found
				delete(spanIDSet, spanIDStr)
			}
		}
	}

View on GitHub (pinned to 806f444784)

Solutions

1. Check the wrapped %w error to distinguish not-found from storage failure.
2. Verify the trace_id corresponds to this Jaeger backend and retention window.
3. Check storage health (index/shard status, connectivity) in jaeger-query logs.
4. Retry the request; for persistent not-found, confirm with trace search that the trace exists.

func validTraceRef(traceID string) bool {
	return len(traceID) == 32 && isHex(traceID) // reject obviously invalid ids before querying
}

out, _, err := handler.Handle(ctx, req, input)
if err != nil && strings.Contains(err.Error(), "failed to get trace") {
	if strings.Contains(err.Error(), "not found") {
		return nil // treat as missing trace, not a failure
	}
	log.Printf("trace fetch failed: %v", err) // check storage health and retry
}

When it happens

Trigger: Requesting span details for a trace_id whose fetch fails: trace not found where backend returns an error, storage read error, context cancellation mid-iteration, or partial/aggregated iteration failure while walking returned traces.

Common situations: Trace expired and purged by retention but still cached in a UI lookup; Elasticsearch shard unavailable; trace ID from another environment/backend queried against the wrong jaeger-query instance.

Related errors

• trace not found
• trace not found
• trace not found
• failed to get dependencies: %w
• failed to get services: %w

AI-assisted analysis of jaegertracing/jaeger@806f444784 (2026-09-01). Data as JSON: /api/errors/b0920bec3467a439. Report an issue: GitHub.