What causes "while extracting scope from bucket %s: %w" in crowdsecurity/crowdsec?

Look at the wrapped inner error (scope filter / empty scope information) for the root cause

while extracting scope from bucket %s: %w

Error message

while extracting scope from bucket %s: %w

What it means

alertFormatSource aggregates the per-event sources of all queued events in an overflowing bucket. It calls SourceFromEvent for each queued event; if any per-event scope extraction fails (e.g. the scope filter evaluation errors), it aborts alert creation and wraps the error naming the bucket. This is a propagation wrapper — the root cause is inside SourceFromEvent (scope filter evaluation).

Source

Thrown at pkg/leakybucket/overflows.go:277

		events = append(events, &ovflwEvent)
	}

	return events
}

// alertFormatSource iterates over the queue to collect sources
func alertFormatSource(leaky *Leaky, queue *pipeline.Queue) (map[string]models.Source, string, error) {
	var source_type string

	sources := make(map[string]models.Source)

	log.Debugf("Formatting (%s) - scope Info : scope_type:%s / scope_filter:%s", leaky.Factory.Spec.Name, leaky.Factory.Spec.ScopeType.Scope, leaky.Factory.Spec.ScopeType.Filter)

	qEvents := queue.GetQueue()
	for idx := range qEvents {
		srcs, err := SourceFromEvent(qEvents[idx], leaky)
		if err != nil {
			return nil, "", fmt.Errorf("while extracting scope from bucket %s: %w", leaky.Factory.Spec.Name, err)
		}

		for key, src := range srcs {
			if source_type == types.Undefined {
				source_type = *src.Scope
			}

			if *src.Scope != source_type {
				return nil, "",
					fmt.Errorf("event has multiple source types : %s != %s", *src.Scope, source_type)
			}

			sources[key] = src
		}
	}

	return sources, source_type, nil
}

View on GitHub (pinned to 909b515798)

Solutions

Look at the wrapped inner error (scope filter / empty scope information) for the root cause
Run the scenario with a debug bucket or cscli hub test to reproduce on the offending events
Fix the scenario's scope filter expression or parser output that made SourceFromEvent fail
Reload the hub (cscli hub reload) after editing the scenario

Defensive patterns

Strategy: try-catch

Validate before calling

// Reproduce before deploy:
// crowdsec -type nginx -config dev.yaml (debug) and check bucket formatting on a sample overflow
cscli metrics  # confirm buckets overflow and alerts are produced

Try / catch

// Where alerts are built programmatically:
alert, err := leakybucket.NewAlert(leaky, queue)
if err != nil {
    log.Errorf("alert creation failed for bucket %s: %v", leaky.Factory.Spec.Name, err)
    return err // surface the chain; inner error names the failing filter
}

Prevention

Fix the root cause reported by the inner SourceFromEvent error, not the wrapper
Test scenarios with debug enabled before production reload
Monitor crowdsec.log for repeated occurrences of this wrapper

When it happens

Trigger: An overflow triggers NewAlert → alertFormatSource; SourceFromEvent returns an error for any queued event (scope filter runtime failure, or RunTimeFilter nil with non-Range scope); the error is wrapped with the bucket name via this message.

Common situations: A scenario whose scope filter breaks only for certain parsed events in the overflow queue — the alert itself then fails to build even though the bucket overflowed; commonly after a parser/hub update changed event shape.

Related errors

AI-assisted analysis of crowdsecurity/crowdsec@909b515798 (2026-09-06). Data as JSON: /api/errors/53f0a3e5e7eb140f. Report an issue: GitHub.