Apache Twill 是一个 Apache Hadoop YARN 的抽象层，减少了开发分布式应用程序的复杂度，允许开发者把精力放在应用逻辑上。Apache Twill 可以让你向使用线程一样来使用 YARN 的分布式编程模型。

示例代码：

public class EchoServer implements TwillRunnable {

  private static Logger LOG = LoggerFactory.getLogger(EchoServer.class);
  private final ServerSocket serverSocket;
  private final int port;

  public EchoServer() {
    ...
  }

  @Override
  public void run() {
    while ( isRunning() ) {
      Socket socket = serverSocket.accept();
      ...
    }
  }
}

运行：

TwillRunnerService runnerService = new YarnTwillRunnerService(
  new YarnConfiguration(), zkConnectStr);
runnerService.startAndWait();

TwillController controller = runnerService.prepare(new EchoServer())
  .addLogHandler(new PrinterLogHandler(new PrintWriter(System.out)))
  .start();

controller.addListener(new ListenerAdapter() {
  @Override
  public void running() {
    LOG.info('Echo Server Started');
  }
}

controller.stop().get();

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