uima-ducc-agent/src/main/java/org/apache/uima/ducc/agent/launcher/ProcessStreamConsumer.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.uima.ducc.agent.launcher;

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

import org.apache.uima.ducc.common.utils.DuccLogger;
import org.apache.uima.ducc.common.utils.id.DuccId;

public class ProcessStreamConsumer extends Thread {
  public static final String LS = System.getProperty("line.separator");

  private InputStream is;

  private PrintStream os;

  DuccLogger logger;

  private DuccId workDuccId;

  private StringBuffer errStreamBuffer = new StringBuffer();

  public ProcessStreamConsumer(DuccLogger logger, ThreadGroup threadGroup, final String threadName,
          InputStream is, PrintStream os, DuccId workDuccId) {
    super(threadGroup, threadName);
    this.os = os;
    this.is = is;
    this.logger = logger;
    setDaemon(true);
    this.workDuccId = workDuccId;
  }

  public String getDataFromStream() {
    return errStreamBuffer.toString();
  }

  public void run() {
    try {

      InputStreamReader in = new InputStreamReader(is);
      BufferedReader reader = new BufferedReader(in);
      String line;
      while ((line = reader.readLine()) != null) {
        line += LS;
        if ("StdErrorReader".equals(Thread.currentThread().getName())) {
          logger.error("ProcessStreamConsumer.run()", workDuccId, line.trim());
          os.print("ERR>>>" + line);
          // Save stderr stream into a local buffer. When the process exits unexpectedly
          // errors will be copied to a Process object.
          errStreamBuffer.append(line.trim());
        } else {
          logger.info("ProcessStreamConsumer.run()", workDuccId, line.trim());
          os.print("OUT>>>" + line);
        }
        // Check if duccling redirected its output streams to a log. If so, it would put
        // out a marker that starts with "1200 Redirecting stdout". This is a clue to
        // stop consuming from the process streams. Just close streams and
        // return.
        if (line.trim().startsWith("1200 Redirecting stdout")) {
          break;
        }
      }
    } catch (Exception x) {
    } finally {
      try {
        os.flush();
      } catch (Exception e) {
        System.out.println("Caught Exception While Flushing " + Thread.currentThread().getName()
                + " Output Stream");
      }
      try {
        if (is != null) {
          is.close();
        }
        logger.debug("ProcessStreamConsumer.run()", workDuccId,
                "Stream Consumer Thread Terminated - Process Streams Redirected to a Log");
      } catch (IOException e) {
        // ignore
      }
    }
  }
}