grafana/k6 · error

invalid stack URL: %w

Error message

invalid stack URL: %w

What it means

resolveCloudTestURL parses the configured stack URL with url.Parse before joining the test path; if parsing fails this error wraps the url package's parse error. url.Parse almost never fails — only malformed input such as control characters, a bad percent-encoding (e.g. '%zz'), or an invalid port triggers it. The stack URL comes from the login config or K6_CLOUD_STACK_URL.

Source

Thrown at internal/cmd/cloud.go:592

	if projectID > 0 {
		tmpCloudConfig["projectID"] = projectID

		b, err := json.Marshal(tmpCloudConfig)
		if err != nil {
			return err
		}

		arc.Options.Cloud = b

		cloudConfig.ProjectID = null.IntFrom(projectID)
	}
	return nil
}

func resolveCloudTestURL(stackURL string, testID int64) (string, error) {
	u, err := url.Parse(stackURL)
	if err != nil {
		return "", fmt.Errorf("invalid stack URL: %w", err)
	}

	return u.JoinPath("a", "k6-app", "tests", strconv.FormatInt(testID, 10)).String(), nil
}

View on GitHub (pinned to 93accf6570)

Solutions

1. Re-run `k6 cloud login` to store a clean, canonical stack URL
2. Fix or unset K6_CLOUD_STACK_URL; it must be a plain absolute URL like https://team.grafana.net
3. Strip whitespace/newlines from CI-injected URL variables

Example fix

# before
export K6_CLOUD_STACK_URL=$'https://team.grafana.net\r'
# after
export K6_CLOUD_STACK_URL=https://team.grafana.net

if raw, ok := os.LookupEnv("K6_CLOUD_STACK_URL"); ok {
    trimmed := strings.TrimSpace(raw)
    u, err := url.Parse(trimmed)
    if err != nil || u.Scheme == "" || u.Host == "" {
        log.Fatalf("K6_CLOUD_STACK_URL=%q is not an absolute URL", raw)
    }
}

func isValidStackURL(raw string) bool {
    u, err := url.Parse(strings.TrimSpace(raw))
    return err == nil && u.Scheme != "" && u.Host != ""
}

When it happens

Trigger: The stored stack URL or K6_CLOUD_STACK_URL contains control characters, invalid escape sequences, or a malformed port (e.g. 'https://team.grafana.net:80x' or a value copied with an embedded newline).

Common situations: Hand-edited config.json; CI variables injected with a trailing newline or carriage return; stack URLs assembled by string concatenation with unescaped characters.

Related errors

• couldn't parse cloud logs host %w
• creating upload request: %w
• invalid stack URL: %w
• stack URL is required to validate token
• Run `k6 cloud login` to authenticate, or check the docs for

AI-assisted analysis of grafana/k6@93accf6570 (2026-08-15). Data as JSON: /api/errors/92a0962b0f2ea434. Report an issue: GitHub.