content: /*
   * 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;
  
  import static alluxio.metrics.sink.MetricsServlet.OBJECT_MAPPER;
  
  import alluxio.conf.Configuration;
  import alluxio.conf.PropertyKey;
  import alluxio.metrics.MetricsSystem;
  import alluxio.util.CommonUtils;
  import alluxio.util.ThreadUtils;
  
  import com.google.common.base.Throwables;
  import com.google.common.collect.ImmutableSet;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.PrintStream;
  import java.nio.ByteBuffer;
  import java.nio.charset.StandardCharsets;
  import java.time.Duration;
  import java.time.Instant;
  import java.time.ZoneId;
  import java.time.format.DateTimeFormatter;
  import java.time.format.FormatStyle;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Locale;
  import java.util.Set;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Future;
  
  /**
   * Utility methods for Alluxio {@link Process}es.
   */
  public final class ProcessUtils {
    private static final Logger LOG = LoggerFactory.getLogger(ProcessUtils.class);
  
    public static final Set<CommonUtils.ProcessType> COLLECT_ON_EXIT =
        ImmutableSet.of(CommonUtils.ProcessType.MASTER, CommonUtils.ProcessType.WORKER);
    public static volatile boolean sInfoDumpOnExitCheck = false;
    public static final DateTimeFormatter DATETIME_FORMAT =
        DateTimeFormatter.ofLocalizedDateTime(FormatStyle.SHORT).ofPattern("yyyyMMdd-HHmmss")
            .withLocale(Locale.getDefault()).withZone(ZoneId.systemDefault());
  
    /**
     * Runs the given {@link Process}. This method should only be called from {@code main()} methods.
     *
     * @param process the {@link Process} to run
     */
    public static void run(Process process) {
      try {
        LOG.info("Starting {}.", process);
        LOG.info("Alluxio version: {}-{}", RuntimeConstants.VERSION, ProjectConstants.REVISION);
        LOG.info("Java version: {}", System.getProperty("java.version"));
        process.start();
        LOG.info("Stopping {}.", process);
  
        dumpInformationOnExit();
  
        System.exit(0);
      } catch (Throwable t) {
        LOG.error("Uncaught exception while running {}, stopping it and exiting. "
            + "Exception \"{}\", Root Cause \"{}\"", process, t, Throwables.getRootCause(t), t);
        try {
          process.stop();
        } catch (Throwable t2) {
          // continue to exit
          LOG.error("Uncaught exception while stopping {}, simply exiting. "
              + "Exception \"{}\", Root Cause \"{}\"", process, t2, Throwables.getRootCause(t2),
              t2);
        }
        dumpInformationOnExit();
  
        System.exit(-1);
      }
    }
  
    /**
     * Logs a fatal error and then exits the system.
     *
     * @param logger the logger to log to
     * @param format the error message format string
     * @param args args for the format string
     */
    public static void fatalError(Logger logger, String format, Object... args) {
      fatalError(logger, new Throwable(), format, args);
    }
  
    /**
     * Logs a fatal error and then exits the system.
     *
     * @param logger the logger to log to
     * @param t the throwable causing the fatal error
     * @param format the error message format string
     * @param args args for the format string
     */
    public static void fatalError(Logger logger, Throwable t, String format, Object... args) {
      String message = String.format("Fatal error: " + format, args);
      if (t != null) {
        message += "\n" + Throwables.getStackTraceAsString(t);
      }
      if (Configuration.getBoolean(PropertyKey.TEST_MODE)) {
        throw new RuntimeException(message);
      }
      logger.error(message);
  
      dumpInformationOnExit();
  
      System.exit(-1);
    }
  
    /**
     * Adds a shutdown hook that will be invoked when a signal is sent to this process.
     *
     * The process may be utilizing some resources, and this shutdown hook will be invoked by
     * JVM when a SIGTERM is sent to the process by "kill" command. The shutdown hook calls
     * {@link Process#stop()} method to cleanly release the resources and exit.
     *
     * @param process the data structure representing the process to terminate
     */
    public static void stopProcessOnShutdown(final Process process) {
      Runtime.getRuntime().addShutdownHook(new Thread(() -> {
        try {
          dumpInformationOnExit();
          process.stop();
        } catch (Throwable t) {
          LOG.error("Failed to stop process", t);
        }
      }, "alluxio-process-shutdown-hook"));
    }
  
    /**
     * Outputs process critical information like metrics and jstack before it exits.
     * This is synchronous in order to capture as much information at the scene as possible.
     * The information will be output to separate files in the log directory.
     */
    public static void dumpInformationOnExit() {
      if (!COLLECT_ON_EXIT.contains(CommonUtils.PROCESS_TYPE.get())) {
        LOG.info("Process type is {}, skip dumping metrics and thread stacks",
            CommonUtils.PROCESS_TYPE.get());
        return;
      }
      if (Configuration.getBoolean(PropertyKey.EXIT_COLLECT_INFO)) {
        synchronized (ProcessUtils.class) {
          if (!sInfoDumpOnExitCheck) {
            sInfoDumpOnExitCheck = true;
            LOG.info("Logging metrics and jstack on {} exit...", CommonUtils.PROCESS_TYPE.get());
            try {
              String logsDir = Configuration.getString(PropertyKey.LOGS_DIR);
              String outputFilePrefix = "alluxio-"
                  + CommonUtils.PROCESS_TYPE.get().toString().toLowerCase() + "-exit";
              dumpMetrics(logsDir, outputFilePrefix);
              dumpStacks(logsDir, outputFilePrefix);
            } catch (Throwable t) {
              LOG.error("Failed to dump metrics and jstacks", t);
            }
          }
        }
      } else {
        LOG.info("Not logging metrics and jstack on exit, set {}=true to enable this feature",
            PropertyKey.EXIT_COLLECT_INFO.getName());
      }
    }
  
    /**
     * Outputs process critical information like metrics and jstack before the primary master
     * fails over to standby. This is asynchronous in order not to block the failover.
     * The information will be output to separate files in the log directory.
     *
     * @param es the thread pool to submit tasks to
     * @return a list of futures for async info dumping jobs
     */
    public static List<Future<Void>> dumpInformationOnFailover(ExecutorService es) {
      if (Configuration.getBoolean(PropertyKey.MASTER_FAILOVER_COLLECT_INFO)) {
        LOG.info("Logging metrics and jstack when primary master switches to standby...");
        String logsDir = Configuration.getString(PropertyKey.LOGS_DIR);
        String outputFilePrefix = "alluxio-"
            + CommonUtils.PROCESS_TYPE.get().toString().toLowerCase() + "-failover";
        List<Future<Void>> futures = new ArrayList<>();
        // Attempt to dump metrics first before MetricsMaster clears all metrics
        // The failover procedure will shutdown RPC -> Journal -> Master components
        // So we rely on the first two steps take longer than this thread
        futures.add(es.submit(() -> {
          ProcessUtils.dumpMetrics(logsDir, outputFilePrefix);
          return null;
        }));
        futures.add(es.submit(() -> {
          ProcessUtils.dumpStacks(logsDir, outputFilePrefix);
          return null;
        }));
        LOG.info("Started dumping metrics and jstacks into {}", logsDir);
        return futures;
      } else {
        LOG.info("Not logging information like metrics and jstack on failover, "
            + "set {}=true to enable this feature",
            PropertyKey.MASTER_FAILOVER_COLLECT_INFO.getName());
        return Collections.emptyList();
      }
    }
  
    private static void dumpMetrics(String logsDir, String outputFilePrefix) {
      Instant start = Instant.now();
      String childFilePath = String.format("%s-metrics-%s.json",
          outputFilePrefix, DATETIME_FORMAT.format(start));
      File metricDumpFile = new File(logsDir, childFilePath);
      try (FileOutputStream fos = new FileOutputStream(metricDumpFile, false)) {
        // The metrics json string is ~100KB in size
        String outputContents = OBJECT_MAPPER.writerWithDefaultPrettyPrinter()
            .writeValueAsString(MetricsSystem.METRIC_REGISTRY);
        fos.getChannel().write(ByteBuffer.wrap(outputContents.getBytes(StandardCharsets.UTF_8)));
      } catch (IOException e) {
        LOG.error("Failed to persist metrics to {}", metricDumpFile.getAbsolutePath(), e);
        return;
      }
      Instant end = Instant.now();
      LOG.info("Dumped metrics of current process in {}ms to {}",
          Duration.between(start, end).toMillis(), childFilePath);
    }
  
    private static void dumpStacks(String logsDir, String outputFilePrefix) {
      Instant start = Instant.now();
      String childFilePath = String.format("%s-stacks-%s.txt",
          outputFilePrefix, DATETIME_FORMAT.format(start));
      File stacksDumpFile = new File(logsDir, childFilePath);
      try (PrintStream stream = new PrintStream(stacksDumpFile)) {
        // Dumping one thread produces <1KB
        ThreadUtils.printThreadInfo(stream, "Dumping all threads in process");
      } catch (IOException e) {
        LOG.error("Failed to persist thread stacks to {}", stacksDumpFile.getAbsolutePath(), e);
        return;
      }
      Instant end = Instant.now();
      LOG.info("Dumped jstack of current process in {}ms to {}",
          Duration.between(start, end).toMillis(), childFilePath);
    }
  
    private ProcessUtils() {} // prevent instantiation
  }
  