org.apache.tajo.cli.ExecExternalShellCommand.java Source code

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Here is the source code for org.apache.tajo.cli.ExecExternalShellCommand.java

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/**
 * 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.tajo.cli;

import java.io.*;
import java.util.concurrent.CountDownLatch;

public class ExecExternalShellCommand extends TajoShellCommand {
    public ExecExternalShellCommand(TajoCli.TajoCliContext context) {
        super(context);
    }

    @Override
    public String getCommand() {
        return "\\!";
    }

    @Override
    public void invoke(String[] command) throws Exception {
        StringBuilder shellCommand = new StringBuilder();
        String prefix = "";
        for (int i = 1; i < command.length; i++) {
            shellCommand.append(prefix).append(command[i]);
            prefix = " ";
        }

        String builtCommand = shellCommand.toString();
        if (command.length < 2) {
            throw new IOException("ERROR: '" + builtCommand + "' is an invalid command.");
        }

        String[] execCommand = new String[3];
        execCommand[0] = "/bin/bash";
        execCommand[1] = "-c";
        execCommand[2] = builtCommand;

        PrintWriter sout = context.getOutput();

        CountDownLatch latch = new CountDownLatch(2);
        Process process = Runtime.getRuntime().exec(execCommand);
        try {
            InputStreamConsoleWriter inWriter = new InputStreamConsoleWriter(process.getInputStream(), sout, "",
                    latch);
            InputStreamConsoleWriter errWriter = new InputStreamConsoleWriter(process.getErrorStream(), sout,
                    "ERROR: ", latch);

            inWriter.start();
            errWriter.start();

            int processResult = process.waitFor();
            latch.await();
            if (processResult != 0) {
                throw new IOException("ERROR: Failed with exit code = " + processResult);
            }
        } finally {
            org.apache.commons.io.IOUtils.closeQuietly(process.getInputStream());
            org.apache.commons.io.IOUtils.closeQuietly(process.getOutputStream());
            org.apache.commons.io.IOUtils.closeQuietly(process.getErrorStream());
        }
    }

    @Override
    public String getUsage() {
        return "<command> [params]";
    }

    @Override
    public String getDescription() {
        return "executes external shell command in TAJO shell";
    }

    static class InputStreamConsoleWriter extends Thread {
        private InputStream in;
        private PrintWriter writer;
        private String prefix;
        private CountDownLatch latch;

        public InputStreamConsoleWriter(InputStream in, PrintWriter writer, String prefix, CountDownLatch latch) {
            this.in = in;
            this.writer = writer;
            this.prefix = prefix;
            this.latch = latch;
        }

        @Override
        public void run() {
            BufferedReader reader = null;
            try {
                reader = new BufferedReader(new InputStreamReader(in));
                String line;
                while ((line = reader.readLine()) != null) {
                    writer.println(prefix + line);
                    writer.flush();
                }
            } catch (Exception e) {
                writer.println("ERROR: " + e.getMessage());
            } finally {
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (IOException e) {
                    }
                }
                latch.countDown();
            }
        }
    }
}