alluxio.master.journal.JournalTool.java Source code

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Here is the source code for alluxio.master.journal.JournalTool.java

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/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.master.journal;

import alluxio.RuntimeConstants;
import alluxio.proto.journal.Journal.JournalEntry;
import alluxio.util.CommonUtils;

import org.apache.commons.cli.BasicParser;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.commons.lang3.StringUtils;

import java.io.IOException;

import javax.annotation.concurrent.NotThreadSafe;

/**
 * Tool for reading the journal. It reads binary journal entries and prints human-readable ones to
 * standard out. Example usage below.
 *
 * <pre>
 * java -cp assembly/target/alluxio-assemblies-0.9.0-SNAPSHOT-jar-with-dependencies.jar \
 *   alluxio.master.journal.JournalTool < journal/FileSystemMaster/log.out
 * </pre>
 */
@NotThreadSafe
public final class JournalTool {
    /** Separator to place at the end of each journal entry. */
    private static final String ENTRY_SEPARATOR = StringUtils.repeat('-', 80);
    /** Amount of time to wait before giving up on the user supplying a journal log via stdin. */
    private static final long TIMEOUT_MS = 2000;
    private static final int EXIT_FAILED = -1;
    private static final int EXIT_SUCCEEDED = 0;
    private static final Options OPTIONS = new Options().addOption("help", false, "Show help for this test")
            .addOption("noTimeout", false, "Wait indefinitely for stdin to supply input");

    private static boolean sNoTimeout = false;
    private static boolean sHelp = false;

    private JournalTool() {
    } // prevent instantiation

    /**
     * Reads a journal via
     * {@code java -cp \
     * assembly/target/alluxio-assemblies-<ALLUXIO-VERSION>-jar-with-dependencies.jar \
     * alluxio.master.journal.JournalTool < journal/FileSystemMaster/log.out}.
     *
     * @param args arguments passed to the tool
     * @throws IOException if a non-Alluxio related exception occurs
     */
    public static void main(String[] args) throws IOException {
        if (!parseInputArgs(args)) {
            usage();
            System.exit(EXIT_FAILED);
        }
        if (sHelp) {
            usage();
            System.exit(EXIT_SUCCEEDED);
        }
        if (!sNoTimeout && !stdinHasData()) {
            System.exit(EXIT_FAILED);
        }

        JournalFormatter formatter = new ProtoBufJournalFormatter();
        JournalInputStream journalStream = formatter.deserialize(System.in);
        JournalEntry entry;
        while ((entry = journalStream.read()) != null) {
            System.out.print(entry);
            System.out.println(ENTRY_SEPARATOR);
        }
    }

    /**
     * Parses the input args with a command line format, using
     * {@link org.apache.commons.cli.CommandLineParser}.
     *
     * @param args the input args
     * @return true if parsing succeeded
     */
    private static boolean parseInputArgs(String[] args) {
        CommandLineParser parser = new BasicParser();
        CommandLine cmd;
        try {
            cmd = parser.parse(OPTIONS, args);
        } catch (ParseException e) {
            System.out.println("Failed to parse input args: " + e);
            return false;
        }
        sNoTimeout = cmd.hasOption("noTimeout");
        sHelp = cmd.hasOption("help");
        return true;
    }

    /**
     * @return true if stdin has data before {@link #TIMEOUT_MS} elapses
     */
    private static boolean stdinHasData() throws IOException {
        long start = System.currentTimeMillis();
        while (System.in.available() == 0) {
            if (System.currentTimeMillis() - start > TIMEOUT_MS) {
                System.out.println("Timed out waiting for input from stdin. Use -noTimeout to wait longer.");
                return false;
            }
            CommonUtils.sleepMs(50);
        }
        return true;
    }

    private static void usage() {
        new HelpFormatter().printHelp(
                "java -cp alluxio-" + RuntimeConstants.VERSION
                        + "-jar-with-dependencies.jar alluxio.master.journal.JournalTool",
                "Read an Alluxio journal from stdin and write it human-readably to stdout", OPTIONS, "", true);
    }
}