grafana/loki · error · logqlmodel.ParseError

invalid regexp parser: %s

Error message

invalid regexp parser: %s

What it means

Error "invalid regexp parser: %s" thrown in grafana/loki.

Source

Thrown at pkg/logql/syntax/ast.go:730

	if e.KeepEmpty {
		sb.WriteString(" ")
		sb.WriteString(OpKeepEmpty)
	}

	return sb.String()
}

type LineParserExpr struct {
	Op    string
	Param string
}

func newLabelParserExpr(op, param string) *LineParserExpr {
	if op == OpParserTypeRegexp {
		_, err := log.NewRegexpParser(param)
		if err != nil {
			panic(logqlmodel.NewParseError(fmt.Sprintf("invalid regexp parser: %s", err.Error()), 0, 0))
		}
	}
	if op == OpParserTypePattern {
		_, err := log.NewPatternParser(param)
		if err != nil {
			panic(logqlmodel.NewParseError(fmt.Sprintf("invalid pattern parser: %s", err.Error()), 0, 0))
		}
	}

	return &LineParserExpr{
		Op:    op,
		Param: param,
	}
}

func (e *LineParserExpr) Shardable(_ bool) bool { return true }

func (e *LineParserExpr) Walk(f WalkFn) { f(e) }

View on GitHub (pinned to 24cfedd4f6)

When it happens

Trigger: Thrown at pkg/logql/syntax/ast.go:730 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/loki@24cfedd4f6 (2026-08-15). Data as JSON: /api/errors/caa9f41f907570a5. Report an issue: GitHub.