com.streamsets.datacollector.util.SystemProcessImpl.java Source code

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/**
 * Copyright 2015 StreamSets Inc.
 *
 * Licensed under 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 com.streamsets.datacollector.util;

import com.google.common.base.Joiner;
import com.google.common.collect.EvictingQueue;
import com.google.common.collect.ImmutableList;
import com.streamsets.pipeline.api.impl.Utils;
import com.streamsets.pipeline.lib.util.ThreadUtil;
import com.streamsets.pipeline.util.SystemProcess;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;
import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

public class SystemProcessImpl implements SystemProcess {
    private static final Logger LOG = LoggerFactory.getLogger(SystemProcessImpl.class);
    private static final AtomicLong fileCounter = new AtomicLong(0);
    private static final int OUT_FILE_LIMIT = 50;
    static final String OUT_EXT = ".out";
    static final String ERR_EXT = ".err";
    private static final Method DESTROY_FORCIBLY;
    static {
        Method destroyForcibly;
        try {
            destroyForcibly = Process.class.getDeclaredMethod("destroyForcibly");
        } catch (NoSuchMethodException e) {
            destroyForcibly = null;
        }
        DESTROY_FORCIBLY = destroyForcibly;
    }
    protected ImmutableList<String> args;
    private final File tempDir;
    private final File input = new File("/dev/null");
    private final File output;
    private final File error;
    private SimpleFileTailer outputTailer;
    private SimpleFileTailer errorTailer;
    private Process delegate;

    SystemProcessImpl(String name, File tempDir, File logDir) {
        String id = nextId();
        this.tempDir = tempDir;
        output = new File(logDir, Utils.format("{}-{}{}", name, id, OUT_EXT));
        error = new File(logDir, Utils.format("{}-{}{}", name, id, ERR_EXT));
    }

    public SystemProcessImpl(String name, File tempDir, List<String> args) {
        clean(tempDir, OUT_FILE_LIMIT);
        String id = nextId();
        output = new File(tempDir, Utils.format("{}-{}{}", name, id, OUT_EXT));
        error = new File(tempDir, Utils.format("{}-{}{}", name, id, ERR_EXT));
        this.tempDir = tempDir;
        this.args = ImmutableList.copyOf(args);
    }

    /**
     * @return a unique number which shorts in descending order
     */
    private static String nextId() {
        NumberFormat numberFormat = NumberFormat.getInstance();
        numberFormat.setMinimumIntegerDigits(10);
        numberFormat.setGroupingUsed(false);
        SimpleDateFormat dateFormat = new SimpleDateFormat("YYYY-MM-dd_HH.mm.ss");
        return Utils.format("{}-{}", dateFormat.format(new Date()),
                numberFormat.format(fileCounter.incrementAndGet()));
    }

    static void clean(File tempDir, int limit) {
        String[] files = tempDir.list(new FilenameFilter() {
            @Override
            public boolean accept(File dir, String name) {
                return name.endsWith(OUT_EXT) || name.endsWith(ERR_EXT);
            }
        });
        if (files != null && files.length > limit) {
            List<String> fileList = new ArrayList<>(files.length);
            fileList.addAll(Arrays.asList(files));
            Collections.sort(fileList);
            while (fileList.size() > limit) {
                File file = new File(tempDir, fileList.remove(0));
                if (!FileUtils.deleteQuietly(file)) {
                    LOG.warn("Could not delete: {}", file);
                }
            }
        }
    }

    @Override
    public void start() throws IOException {
        start(new HashMap<String, String>());
    }

    @Override
    public void start(Map<String, String> env) throws IOException {
        Utils.checkState(output.createNewFile(), Utils.formatL("Could not create output file: {}", output));
        Utils.checkState(error.createNewFile(), Utils.formatL("Could not create error file: {}", error));
        Utils.checkState(delegate == null, "start can only be called once");
        LOG.info("Standard output for process written to file: " + output);
        LOG.info("Standard error for process written to file: " + error);
        ProcessBuilder processBuilder = new ProcessBuilder().redirectInput(input).redirectOutput(output)
                .redirectError(error).directory(tempDir).command(args);
        processBuilder.environment().putAll(env);
        LOG.info("Starting: " + args);
        delegate = processBuilder.start();
        ThreadUtil.sleep(100); // let it start
        outputTailer = new SimpleFileTailer(output);
        errorTailer = new SimpleFileTailer(error);
    }

    @Override
    public String getCommand() {
        return Joiner.on(" ").join(args);
    }

    @Override
    public boolean isAlive() {
        return delegate != null && isAlive(delegate);
    }

    @Override
    public void cleanup() {
        if (outputTailer != null) {
            outputTailer.close();
        }
        if (errorTailer != null) {
            errorTailer.close();
        }
        kill(5000);
    }

    @Override
    public Collection<String> getAllOutput() {
        if (outputTailer != null) {
            return outputTailer.getAllData();
        }
        return new ArrayList<>();
    }

    @Override
    public Collection<String> getAllError() {
        if (errorTailer != null) {
            return errorTailer.getAllData();
        }
        return new ArrayList<>();
    }

    @Override
    public Collection<String> getOutput() {
        if (outputTailer != null) {
            return outputTailer.getData();
        }
        return new ArrayList<>();
    }

    @Override
    public Collection<String> getError() {
        if (errorTailer != null) {
            return errorTailer.getData();
        }
        return new ArrayList<>();
    }

    @Override
    public void kill(long timeoutBeforeForceKill) {
        if (outputTailer != null) {
            outputTailer.close();
        }
        if (errorTailer != null) {
            errorTailer.close();
        }
        if (delegate != null && isAlive(delegate)) {
            delegate.destroy();
            long start = System.currentTimeMillis();
            while (isAlive(delegate) && (System.currentTimeMillis() - start) > timeoutBeforeForceKill) {
                if (!ThreadUtil.sleep(100)) {
                    break;
                }
            }
            if (isAlive(delegate)) {
                if (DESTROY_FORCIBLY != null) {
                    try {
                        DESTROY_FORCIBLY.invoke(delegate);
                    } catch (Exception e) {
                        LOG.error("Error trying to call destroyForcibly on {}: {}", delegate, e, e);
                    }
                }
            }
        }
    }

    @Override
    public String toString() {
        return Utils.format("SystemProcess: {} ", Joiner.on(" ").join(args));
    }

    @Override
    public int exitValue() {
        return delegate.exitValue();
    }

    @Override
    public boolean waitFor(long timeout, TimeUnit unit) {
        return waitFor(delegate, timeout, unit);
    }

    /**
     * Java 1.7 does not have Process.isAlive
     */
    private static boolean isAlive(Process process) {
        try {
            process.exitValue();
            return false;
        } catch (IllegalThreadStateException e) {
            return true;
        }
    }

    /**
     * Java 1.7 does not have Process.waitFor(timeout)
     */
    private static boolean waitFor(Process process, long timeout, TimeUnit unit) {
        long startTime = System.nanoTime();
        long rem = unit.toNanos(timeout);
        do {
            try {
                process.exitValue();
                return true;
            } catch (IllegalThreadStateException ex) {
                if (rem > 0)
                    ThreadUtil.sleep(Math.min(TimeUnit.NANOSECONDS.toMillis(rem) + 1, 100));
            }
            rem = unit.toNanos(timeout) - (System.nanoTime() - startTime);
        } while (rem > 0);
        return false;
    }

    private static class SimpleFileTailer {
        private final File file;
        private final EvictingQueue<String> history;
        private final RandomAccessFile randomAccessFile;
        private final byte[] inbuf;

        public SimpleFileTailer(File file) {
            this.file = file;
            this.history = EvictingQueue.create(2500);
            this.inbuf = new byte[8192 * 8];
            try {
                this.randomAccessFile = new RandomAccessFile(file, "r");
            } catch (FileNotFoundException e) {
                throw new RuntimeException(Utils.format("Unexpected error reading output file '{}': {}", file, e),
                        e);
            }
        }

        public void close() {
            IOUtils.closeQuietly(randomAccessFile);
        }

        public List<String> getData() {
            List<String> result = new ArrayList<>();
            try {
                readLines(randomAccessFile, result);
            } catch (IOException e) {
                throw new RuntimeException(Utils.format("Error reading from '{}': {}", file, e, e));
            }
            history.addAll(result);
            return result;
        }

        public Collection<String> getAllData() {
            EvictingQueue<String> result = EvictingQueue.create(2500);
            BufferedReader reader = null;
            try {
                reader = new BufferedReader(new FileReader(file));
                String line;
                while ((line = reader.readLine()) != null) {
                    result.add(line);
                }
            } catch (IOException e) {
                String msg = Utils.format("Error reading from command output file '{}': {}", file, e);
                throw new RuntimeException(msg, e);
            } finally {
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (IOException ex) {
                        // ignored
                    }
                }
            }
            return result;
        }

        /**
         * Read new lines.
         *
         * @param reader The file to read
         * @return The new position after the lines have been read
         * @throws java.io.IOException if an I/O error occurs.
         */
        private long readLines(final RandomAccessFile reader, List<String> result) throws IOException {
            ByteArrayOutputStream lineBuf = new ByteArrayOutputStream(64);
            long pos = reader.getFilePointer();
            long rePos = pos; // position to re-read
            int num;
            boolean seenCR = false;
            while (((num = reader.read(inbuf)) != -1)) {
                for (int i = 0; i < num; i++) {
                    final byte ch = inbuf[i];
                    switch (ch) {
                    case '\n':
                        seenCR = false; // swallow CR before LF
                        result.add(new String(lineBuf.toByteArray(), StandardCharsets.UTF_8));
                        lineBuf.reset();
                        rePos = pos + i + 1;
                        break;
                    case '\r':
                        if (seenCR) {
                            lineBuf.write('\r');
                        }
                        seenCR = true;
                        break;
                    default:
                        if (seenCR) {
                            seenCR = false; // swallow final CR
                            result.add(new String(lineBuf.toByteArray(), StandardCharsets.UTF_8));
                            lineBuf.reset();
                            rePos = pos + i + 1;
                        }
                        lineBuf.write(ch);
                    }
                }
                pos = reader.getFilePointer();
            }
            IOUtils.closeQuietly(lineBuf); // not strictly necessary
            reader.seek(rePos); // Ensure we can re-read if necessary
            return rePos;
        }
    }
}