content: /*
   * 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.cassandra.utils.binlog;
  
  import java.io.File; // checkstyle: permit this import
  import java.io.IOException;
  import java.nio.file.Path;
  import java.util.concurrent.DelayQueue;
  import java.util.concurrent.Delayed;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.TimeUnit;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import com.google.common.annotations.VisibleForTesting;
  import com.google.common.primitives.Longs;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import net.openhft.chronicle.queue.impl.single.SingleChronicleQueue;
  import org.apache.cassandra.utils.FBUtilities;
  import org.apache.cassandra.utils.concurrent.UncheckedInterruptedException;
  
  import static java.util.concurrent.TimeUnit.MILLISECONDS;
  import static org.apache.cassandra.concurrent.ExecutorFactory.Global.executorFactory;
  import static org.apache.cassandra.utils.Clock.Global.currentTimeMillis;
  
  /**
   * Archives binary log files immediately when they are rolled using a configure archive command.
   *
   * The archive command should be "/path/to/script.sh %path" where %path will be replaced with the file to be archived
   */
  public class ExternalArchiver implements BinLogArchiver
  {
      private static final Logger logger = LoggerFactory.getLogger(ExternalArchiver.class);
      // used to replace %path with the actual file to archive when calling the archive command
      private static final Pattern PATH = Pattern.compile("%path");
      private static final long DEFAULT_RETRY_DELAY_MS = TimeUnit.MILLISECONDS.convert(5, TimeUnit.MINUTES);
  
      /**
       * use a DelayQueue to simplify retries - we want first tries to be executed immediately and retries should wait DEFAULT_RETRY_DELAY_MS
       */
      private final DelayQueue<DelayFile> archiveQueue = new DelayQueue<>();
      private final String archiveCommand;
      private final ExecutorService executor = executorFactory().sequential("BinLogArchiver");
      private final Path path;
      /**
       * for testing, to be able to make sure that the command is executed
       */
      private final ExecCommand commandExecutor;
      private volatile boolean shouldContinue = true;
  
      public ExternalArchiver(String archiveCommand, Path path, int maxArchiveRetries)
      {
          this(archiveCommand, path, DEFAULT_RETRY_DELAY_MS, maxArchiveRetries, ExternalArchiver::exec);
      }
  
      @VisibleForTesting
      ExternalArchiver(String archiveCommand, Path path, long retryDelayMs, int maxRetries, ExecCommand command)
      {
          this.archiveCommand = archiveCommand;
          this.commandExecutor = command;
          // if there are any .cq4 files in path, archive them on startup - this handles any leftover files from crashes etc
          archiveExisting(path);
          this.path = path;
  
          executor.execute(() -> {
             while (shouldContinue)
             {
                 DelayFile toArchive = null;
                 try
                 {
                     toArchive = archiveQueue.poll(100, TimeUnit.MILLISECONDS);
                     if (toArchive != null)
                         archiveFile(toArchive.file);
                 }
                 catch (Throwable t)
                 {
                     if (toArchive != null)
                     {
  
                         if (toArchive.retries < maxRetries)
                         {
                             logger.error("Got error archiving {}, retrying in {} minutes", toArchive.file, TimeUnit.MINUTES.convert(retryDelayMs, TimeUnit.MILLISECONDS), t);
                             archiveQueue.add(new DelayFile(toArchive.file, retryDelayMs, TimeUnit.MILLISECONDS, toArchive.retries + 1));
                         }
                         else
                         {
                             logger.error("Max retries {} reached for {}, leaving on disk", toArchive.retries, toArchive.file, t);
                         }
                     }
                     else
                         logger.error("Got error waiting for files to archive", t);
                 }
             }
             logger.debug("Exiting archiver thread");
          });
      }
  
      public void onReleased(int cycle, File file)
      {
          logger.debug("BinLog file released: {}", file);
          archiveQueue.add(new DelayFile(file, 0, TimeUnit.MILLISECONDS, 0));
      }
  
      /**
       * Stops the archiver thread and tries to archive all existing files
       *
       * this handles the case where a user explicitly disables full/audit log and would expect all log files to be archived
       * rolled or not
       */
      public void stop()
      {
          shouldContinue = false;
          try
          {
              // wait for the archiver thread to stop;
              executor.submit(() -> {}).get();
              // and try to archive all remaining files before exiting
              archiveExisting(path);
          }
          catch (InterruptedException e)
          {
              throw new UncheckedInterruptedException(e);
          }
          catch (ExecutionException e)
          {
              throw new RuntimeException(e);
          }
      }
  
      /**
       * Iterates over all files in path, executing the archive command for each.
       */
      private void archiveExisting(Path path)
      {
          if (path == null)
              return;
          for (File f : path.toFile().listFiles((f) -> f.isFile() && f.getName().endsWith(SingleChronicleQueue.SUFFIX))) // checkstyle: permit this invocation
          {
              try
              {
                  logger.debug("Archiving existing file {}", f);
                  archiveFile(f);
              }
              catch (IOException e)
              {
                  logger.error("Got error archiving existing file {}", f, e);
              }
          }
      }
  
      private void archiveFile(File f) throws IOException
      {
          String cmd = PATH.matcher(archiveCommand).replaceAll(Matcher.quoteReplacement(f.getAbsolutePath()));
          logger.debug("Executing archive command: {}", cmd);
          commandExecutor.exec(cmd);
      }
  
      static void exec(String command) throws IOException
      {
          ProcessBuilder pb = new ProcessBuilder(command.split(" "));
          pb.redirectErrorStream(true);
          FBUtilities.exec(pb);
      }
  
      private static class DelayFile implements Delayed
      {
          public final File file;
          private final long delayTime;
          private final int retries;
  
          public DelayFile(File file, long delay, TimeUnit delayUnit, int retries)
          {
              this.file = file;
              this.delayTime = currentTimeMillis() + MILLISECONDS.convert(delay, delayUnit);
              this.retries = retries;
          }
          public long getDelay(TimeUnit unit)
          {
              return unit.convert(delayTime - currentTimeMillis(), TimeUnit.MILLISECONDS);
          }
  
          public int compareTo(Delayed o)
          {
              DelayFile other = (DelayFile)o;
              return Longs.compare(delayTime, other.delayTime);
          }
      }
  
      interface ExecCommand
      {
          public void exec(String command) throws IOException;
      }
  }
  