grafana/k6 · error · ErrInvalidURLScheme

invalid URL scheme: %q

Error message

invalid URL scheme: %q

What it means

A validation guard in parseURL that wraps ErrInvalidURLScheme. It fires when the URL given in the otel config uses a scheme other than http or https (e.g. grpc:// or ftp://). The at-fault input is the malformed otel URL's scheme.

Source

Thrown at internal/lib/trace/otel.go:227

			return params, fmt.Errorf("unknown otel config key %s", key)
		}
	}

	if params.proto == "grpc" && params.urlPath != "" {
		return params, ErrInvalidGRPCWithURLPath
	}

	return params, nil
}

func (p *tracerProviderParams) parseURL(s string) error {
	u, err := url.Parse(s)
	if err != nil {
		return err
	}

	if u.Scheme != "http" && u.Scheme != "https" {
		return fmt.Errorf("%w: %q", ErrInvalidURLScheme, u.Scheme)
	}

	p.proto = "http"
	p.endpoint = u.Host
	p.urlPath = u.Path
	p.insecure = u.Scheme == "http"

	return nil
}

func (p *tracerProviderParams) parseProto(proto string) error {
	if proto != "http" && proto != "grpc" {
		return fmt.Errorf("%w: %q", ErrInvalidProto, proto)
	}

	p.proto = proto

	return nil

View on GitHub (pinned to 01ffac6f24)

Solutions

1. Use an http:// or https:// URL for the otel endpoint
2. For gRPC protocol, set proto=grpc and give the host:port endpoint without a URL path
3. Check that the URL was not truncated or corrupted in the config

When it happens

Trigger: Thrown at internal/lib/trace/otel.go:227 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/ebad2ae1bf186d22. Report an issue: GitHub.