func DownloadBinary()

in httputil/httputil.go [172:234]
51 lines of code
12 McCabe index (conditional complexity)

func DownloadBinary(originURL, destDir, destFile string) (string, error) {
	err := os.MkdirAll(destDir, 0755)
	if err != nil {
		return "", fmt.Errorf("could not create directory %s: %v", destDir, err)
	}
	destinationPath := filepath.Join(destDir, destFile)

	if _, err := os.Stat(destinationPath); err != nil {
		tmpfile, err := ioutil.TempFile(destDir, "download")
		if err != nil {
			return "", fmt.Errorf("could not create temporary file: %v", err)
		}
		defer func() {
			err := tmpfile.Close()
			if err == nil {
				os.Remove(tmpfile.Name())
			}
		}()

		u, err := url.Parse(originURL)
		if err != nil {
			// originURL supposed to be valid
			return "", err
		}

		log.Printf("Downloading %s...", originURL)

		var auth string = ""
		t, err := tryFindNetrcFileCreds(u.Host)
		if err == nil {
			// successfully parsed netrc for given host
			auth = t
		}

		resp, err := get(originURL, auth)
		if err != nil {
			return "", fmt.Errorf("HTTP GET %s failed: %v", originURL, err)
		}
		defer resp.Body.Close()

		if resp.StatusCode != 200 {
			return "", fmt.Errorf("HTTP GET %s failed with error %v", originURL, resp.StatusCode)
		}

		_, err = io.Copy(tmpfile, resp.Body)
		if err != nil {
			return "", fmt.Errorf("could not copy from %s to %s: %v", originURL, tmpfile.Name(), err)
		}

		err = os.Chmod(tmpfile.Name(), 0755)
		if err != nil {
			return "", fmt.Errorf("could not chmod file %s: %v", tmpfile.Name(), err)
		}

		tmpfile.Close()
		err = os.Rename(tmpfile.Name(), destinationPath)
		if err != nil {
			return "", fmt.Errorf("could not move %s to %s: %v", tmpfile.Name(), destinationPath, err)
		}
	}

	return destinationPath, nil
}