private String getUrl(AbstractBuild build) {
    Node node = build.getBuiltOn();
    if (node instanceof DockerSlave) {
      DockerSlave slave = (DockerSlave) node;
      return slave.getCloud().serverUrl;
    }

    return null;
  }
  private DockerClient getDockerClient(AbstractBuild build) {

    Node node = build.getBuiltOn();
    if (node instanceof DockerSlave) {
      DockerSlave slave = (DockerSlave) node;
      return slave.getCloud().connect();
    }

    return null;
  }