gistfile1.php

/**
 * Wrapper to execute a remote command over ssh.
 * @param $ssh     Connection from ssh2_connect
 * @param $command string to execute on shell
 * @returns string
 */
function ssh2_exec_command($ssh, $command, $retry = 5) {
  // The `sleep` is a nasty hack to account for some kind of timing bug in ssh2
  $sleep = 0;
  $stream = false;
  while (!$stream) {
    $stream = ssh2_exec($ssh, "sleep {$sleep} ; " . $command);
    $sleep = $sleep + 2;
    if ($sleep > 60) {
      throw new Exception("Unable to execute command");
    }
  }
  stream_set_timeout($stream, 10);
  stream_set_blocking($stream, true);
  $data = stream_get_contents($stream);
  fclose($stream);
  if (!$data && $retry > 0) {
    // On failure, retry
    return ssh2_exec_command($command, $retry - 1);
  }
  return $data;
}

How about backing off with a doubling timeout? First 1 second, then 2, then 4, etc.

Goog idea.