SigNoz/signoz · error

existingFilterItems must contain a valid key

Error message

existingFilterItems must contain a valid key

What it means

FilterAttributeValueRequest.Validate() iterates ExistingFilterItems and fails if any item's Key.Key is empty. Existing filters constrain the value search, and each must reference a real attribute key.

Source

Thrown at pkg/query-service/model/v3/v3.go:346

		return fmt.Errorf("startTimeMillis is required")
	}

	if f.EndTimeMillis == 0 {
		return fmt.Errorf("endTimeMillis is required")
	}

	if f.Limit == 0 {
		f.Limit = 100
	}

	if f.Limit > 1000 {
		return fmt.Errorf("limit must be less than 1000")
	}

	if f.ExistingFilterItems != nil {
		for _, value := range f.ExistingFilterItems {
			if value.Key.Key == "" {
				return fmt.Errorf("existingFilterItems must contain a valid key")
			}
		}
	}

	if err := f.DataSource.Validate(); err != nil {
		return fmt.Errorf("invalid data source: %w", err)
	}

	if f.DataSource != DataSourceMetrics {
		if err := f.AggregateOperator.Validate(); err != nil {
			return fmt.Errorf("invalid aggregate operator: %w", err)
		}
	}

	return nil
}

type AggregateAttributeResponse struct {

View on GitHub (pinned to 5069bf80b0)

Solutions

1. Prune filter items whose Key.Key is empty before sending the request
2. Ensure each existingFilterItems entry has a fully populated Key object with a non-empty key string
3. Add client-side validation that a filter row is complete before it enters the request

Example fix

// before
"existingFilterItems":[{"key":{"key":"","dataType":"string"},"value":"x","operator":"="}]

// after
"existingFilterItems":[{"key":{"key":"http.method","dataType":"string"},"value":"GET","operator":"="}]

for _, it := range req.ExistingFilterItems { if it.Key.Key == "" { return errors.New("existingFilterItems contains empty key") } }

func existingFiltersComplete(items []v3.FilterItem) bool { for _, it := range items { if it.Key.Key == "" { return false } }; return true }

When it happens

Trigger: Sending existingFilterItems in the attribute_value request where an entry has {"key":{"key":"","dataType":"string",...}} — e.g. a filter row added in the UI but with no attribute chosen yet, or a stale filter item with an empty key field.

Common situations: Filter builder state serializing incomplete rows, clients reusing FilterItem structs where only Key was partially populated, migration code dropping the key field.

Understand the failure class

Background: "Missing required field" and "field is required" errors: why libraries reject payloads that omit mandatory fields — this error's family across 20 libraries.

Related errors

• filterAttributeKey is required
• ErrCodeInvalidInput
• invalid value for key %s: %v
• unsupported operator %s
• invalid operator: %s

AI-assisted analysis of SigNoz/signoz@5069bf80b0 (2026-08-28). Data as JSON: /api/errors/8a0ffe048a8445e5. Report an issue: GitHub.