SigNoz/signoz · error

invalid expression %s: %v

Error message

invalid expression %s: %v

What it means

In query-builder validation, each expression string is compiled with govaluate.NewEvaluableExpressionWithFunctions. If the expression has syntax errors (unbalanced parens, bad tokens, unknown function names not in the allowed funcs map), this error is collected.

Source

Thrown at pkg/query-service/app/parser.go:713

	var expressions []string
	for _, q := range qp.CompositeQuery.BuilderQueries {
		expressions = append(expressions, q.Expression)
	}
	errs := validateExpressions(expressions, queryBuilder.EvalFuncs, qp.CompositeQuery)
	if len(errs) > 0 {
		return multierr.Combine(errs...)
	}
	return nil
}

// validateExpressions validates the math expressions using the list of
// allowed functions.
func validateExpressions(expressions []string, funcs map[string]govaluate.ExpressionFunction, cq *v3.CompositeQuery) []error {
	var errs []error
	for _, exp := range expressions {
		evalExp, err := govaluate.NewEvaluableExpressionWithFunctions(exp, funcs)
		if err != nil {
			errs = append(errs, fmt.Errorf("invalid expression %s: %v", exp, err))
			continue
		}
		for _, v := range evalExp.Vars() {
			var hasVariable bool
			for _, q := range cq.BuilderQueries {
				if q.Expression == v {
					hasVariable = true
					break
				}
			}
			if !hasVariable {
				errs = append(errs, fmt.Errorf("unknown variable %s", v))
			}
		}
	}
	return errs
}

View on GitHub (pinned to 5069bf80b0)

Solutions

1. Fix the arithmetic/functional expression syntax (balanced parens, valid operators)
2. Verify every function used exists in the allowed functions for your version (see constants/functions docs)
3. Test the expression locally with govaluate or in the UI formula box first

Example fix

// before
{"expression": "A +"}
// after
{"expression": "A + B"}

if _, err := govaluate.NewEvaluableExpressionWithFunctions(expr, allowedFuncs); err != nil { return fmt.Errorf("bad expression: %v", err) }

Aggregate the errs slice returned by validateExpressions and show all expression errors at once in the UI/API response.

When it happens

Trigger: POST /api/v3/query_range with a builder query expression like 'A + ' , 'sum(', or using a function not in the allowed function map for your SigNoz version.

Common situations: Hand-crafting formulas in the query builder UI/API; using newly added functions against an older SigNoz; copy-paste introducing smart quotes or invisible characters.

Related errors

• error building clickhouse query: %v
• unknown variable %s
• live tail is only supported for single query
• invalid data type for resource attribute: %s
• unsupported operation, exists and not exists can only be app

AI-assisted analysis of SigNoz/signoz@5069bf80b0 (2026-08-28). Data as JSON: /api/errors/ac5e6e7faf192b5d. Report an issue: GitHub.