tsenart/vegeta · error

bad URL: %s, %w

Error message

bad URL: %s, %w

What it means

Returned when the URL portion of a target line fails url.ParseRequestURI. The method was valid but the second token is not a parseable absolute request URI.

Source

Thrown at lib/targets.go:300

			}
		}

		tgt.Body = body
		tgt.Header = http.Header{}
		for k, vs := range hdr {
			tgt.Header[k] = vs
		}

		tokens := strings.SplitN(line, " ", 2)
		if len(tokens) < 2 {
			return fmt.Errorf("bad target: %s", line)
		}
		if !startsWithHTTPMethod(line) {
			return fmt.Errorf("bad method: %s", tokens[0])
		}
		tgt.Method = tokens[0]
		if _, err = url.ParseRequestURI(tokens[1]); err != nil {
			return fmt.Errorf("bad URL: %s, %w", tokens[1], err)
		}
		tgt.URL = tokens[1]
		line = strings.TrimSpace(sc.Peek())
		if line == "" || startsWithHTTPMethod(line) {
			return nil
		}
		for sc.Scan() {
			if line = strings.TrimSpace(sc.Text()); line == "" {
				break
			} else if strings.HasPrefix(line, "#") {
				continue
			} else if strings.HasPrefix(line, "@") {
				if tgt.Body, err = os.ReadFile(line[1:]); err != nil {
					return fmt.Errorf("bad body: %w", err)
				}
				break
			}
			tokens = strings.SplitN(line, ":", 2)

View on GitHub (pinned to cf58112690)

Solutions

  1. Provide an absolute URL including scheme and host, e.g. "GET http://localhost:8080/path".
  2. Percent-encode or quote special characters in the URL.
  3. Inspect the URL text shown in the error and run it through url.ParseRequestURI locally to confirm validity.
  4. Shell-quote URLs containing ? and & so the targets file ends up intact.

Example fix

// before
GET localhost:8080/hello?a=1&b=2
// after
GET http://localhost:8080/hello?a=1&b=2
Defensive patterns

Strategy: validation

Validate before calling

func validURL(u string) error {
    _, err := url.ParseRequestURI(u)
    return err
}
// ensure scheme present
func hasScheme(u string) bool { return strings.HasPrefix(u, "http://") || strings.HasPrefix(u, "https://") }

Try / catch

if _, err := vegeta.NewTargets(r); err != nil {
    if strings.Contains(err.Error(), "bad URL:") {
        return fmt.Errorf("targets need absolute http(s) URLs: %w", err)
    }
    return err
}

Prevention

When it happens

Trigger: Target lines with malformed URLs: missing scheme ("GET localhost:8080/"), invalid characters or spaces in the URL, or an empty URL token.

Common situations: Writing relative paths instead of absolute URLs in targets files, unencoded special characters (#, spaces, quotes) in URLs, shell variable expansion gone wrong leaving "" or partial URLs.

Related errors

AI-assisted analysis of tsenart/vegeta@cf58112690 (2026-08-31). Data as JSON: /api/errors/74c43575c751201b. Report an issue: GitHub.