utility to download badge for go test coverage

badge.go

func badgedl(pct float64) error {
	color := ""
	switch {
	case pct < 50:
		color = "orange"
	case pct < 60:
		color = "yellow"
	case pct < 70:
		color = "yellowgreen"
	case pct < 80:
		color = "green"
	case pct < 90:
		color = "brightgreen"
	default:
		color = "red"
	}
	u := "https://img.shields.io/badge/"
	format := "coverage-%.1f%%-%s.svg"
	u += url.QueryEscape(fmt.Sprintf(format, pct, color))
	fmt.Println("downloading badge:", u)
	if err := download(u, ".github/coverage.svg"); err != nil {
		return fmt.Errorf("badge: %w", err)
	}

	return nil
}

func download(url, path string) error {
	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		return err
	}
	// req.Header.Set("Content-Type", "application/json")

	client := http.Client{Timeout: 30 * time.Second}
	res, err := client.Do(req)
	if err != nil {
		return err
	}
	defer func() {
		err = errors.Join(err, res.Body.Close())
	}()

	if res.StatusCode >= 400 {
		return fmt.Errorf("status: %s, url: %s", res.Status, url)
	}
	b, err := io.ReadAll(res.Body)
	if err != nil {
		return err
	}
	err = writeBadge(path, b)
	return err
}