DistributedShell.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.twill.yarn;

import com.google.common.base.Charsets;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import org.apache.twill.api.AbstractTwillRunnable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 *
 */
public final class DistributedShell extends AbstractTwillRunnable {

  private static final Logger LOG = LoggerFactory.getLogger(DistributedShell.class);

  public DistributedShell(String...commands) {
    super(ImmutableMap.of("cmds", Joiner.on(';').join(commands)));
  }

  @Override
  public void run() {
    for (String cmd : Splitter.on(';').split(getArgument("cmds"))) {
      try {
        Process process = new ProcessBuilder(ImmutableList.copyOf(Splitter.on(' ').split(cmd)))
                              .redirectErrorStream(true).start();
        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream(), Charsets.US_ASCII));
        try {
          String line = reader.readLine();
          while (line != null) {
            LOG.info(line);
            line = reader.readLine();
          }
        } finally {
          reader.close();
        }
      } catch (IOException e) {
        LOG.error("Fail to execute command " + cmd, e);
      }
    }
  }

  @Override
  public void stop() {
    // No-op
  }
}