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 com.alibaba.jstorm.blobstore;
  
  import backtype.storm.Config;
  import com.alibaba.jstorm.utils.JStormUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.nio.file.Files;
  import java.util.*;
  
  /**
   * Very basic blob store impl with no ACL handling.
   */
  public class FileBlobStoreImpl {
      private static final long FULL_CLEANUP_FREQ = 60 * 60 * 1000L;
      private static final int BUCKETS = 1024;
      private static final Logger LOG = LoggerFactory.getLogger(FileBlobStoreImpl.class);
      private static final Timer timer = new Timer("FileBlobStore cleanup thread", true);
  
      public class KeyInHashDirIterator implements Iterator<String> {
          private int currentBucket = 0;
          private Iterator<String> it = null;
          private String next = null;
  
          public KeyInHashDirIterator() throws IOException {
              primeNext();
          }
  
          private void primeNext() throws IOException {
              while (it == null && currentBucket < BUCKETS) {
                  String name = String.valueOf(currentBucket);
                  File dir = new File(fullPath, name);
                  try {
                      it = listKeys(dir);
                  } catch (FileNotFoundException e) {
                      it = null;
                  }
                  if (it == null || !it.hasNext()) {
                      it = null;
                      currentBucket++;
                  } else {
                      next = it.next();
                  }
              }
          }
  
          @Override
          public boolean hasNext() {
              return next != null;
          }
  
          @Override
          public String next() {
              if (!hasNext()) {
                  throw new NoSuchElementException();
              }
              String current = next;
              next = null;
              if (it != null) {
                  if (!it.hasNext()) {
                      it = null;
                      currentBucket++;
                      try {
                          primeNext();
                      } catch (IOException e) {
                          throw new RuntimeException(e);
                      }
                  } else {
                      next = it.next();
                  }
              }
              return current;
          }
  
          @Override
          public void remove() {
              throw new UnsupportedOperationException("Delete Not Supported");
          }
      }
  
      private File fullPath;
      private TimerTask cleanup = null;
  
      public FileBlobStoreImpl(File path, Map<String, Object> conf) throws IOException {
          LOG.info("Creating new blob store based in {}", path);
          fullPath = path;
          fullPath.mkdirs();
          Object shouldCleanup = conf.get(Config.BLOBSTORE_CLEANUP_ENABLE);
          if (JStormUtils.parseBoolean(shouldCleanup, false)) {
              LOG.debug("Starting File blobstore cleaner");
              cleanup = new TimerTask() {
                  @Override
                  public void run() {
                      try {
                          fullCleanup(FULL_CLEANUP_FREQ);
                      } catch (IOException e) {
                          LOG.error("Error trying to cleanup", e);
                      }
                  }
              };
              timer.scheduleAtFixedRate(cleanup, 0, FULL_CLEANUP_FREQ);
          }
      }
  
      /**
       * @return all keys that are available for reading.
       * @throws IOException on any error.
       */
      public Iterator<String> listKeys() throws IOException {
          return new KeyInHashDirIterator();
      }
  
      /**
       * Get an input stream for reading a part.
       * @param key the key of the part to read.
       * @return the where to read the data from.
       * @throws IOException on any error
       */
      public LocalFsBlobStoreFile read(String key) throws IOException {
          return new LocalFsBlobStoreFile(getKeyDir(key), BlobStoreFile.BLOBSTORE_DATA_FILE);
      }
  
      /**
       * Get an object tied to writing the data.
       * @param key the key of the part to write to.
       * @return an object that can be used to both write to, but also commit/cancel the operation.
       * @throws IOException on any error
       */
      public LocalFsBlobStoreFile write(String key, boolean create) throws IOException {
          return new LocalFsBlobStoreFile(getKeyDir(key), true, create);
      }
  
      /**
       * Check if the key exists in the blob store.
       * @param key the key to check for
       * @return true if it exists else false.
       */
      public boolean exists(String key) {
          return getKeyDir(key).exists();
      }
  
      /**
       * Delete a key from the blob store
       * @param key the key to delete
       * @throws IOException on any error
       */
      public void deleteKey(String key) throws IOException {
          File keyDir = getKeyDir(key);
          LocalFsBlobStoreFile pf = new LocalFsBlobStoreFile(keyDir, BlobStoreFile.BLOBSTORE_DATA_FILE);
          pf.delete();
          delete(keyDir);
      }
  
      private File getKeyDir(String key) {
          String hash = String.valueOf(Math.abs((long)key.hashCode()) % BUCKETS);
          File ret = new File(new File(fullPath, hash), key);
          LOG.debug("{} Looking for {} in {}", new Object[]{fullPath, key, hash});
          return ret;
      }
  
      public void fullCleanup(long age) throws IOException {
          long cleanUpIfBefore = System.currentTimeMillis() - age;
          Iterator<String> keys = new KeyInHashDirIterator();
          while (keys.hasNext()) {
              String key = keys.next();
              File keyDir = getKeyDir(key);
              Iterator<LocalFsBlobStoreFile> i = listBlobStoreFiles(keyDir);
              if (!i.hasNext()) {
                  //The dir is empty, so try to delete it, may fail, but that is OK
                  try {
                      keyDir.delete();
                  } catch (Exception e) {
                      LOG.warn("Could not delete "+keyDir+" will try again later");
                  }
              }
              while (i.hasNext()) {
                  LocalFsBlobStoreFile f = i.next();
                  if (f.isTmp()) {
                      if (f.getModTime() <= cleanUpIfBefore) {
                          f.delete();
                      }
                  }
              }
          }
      }
  
      protected Iterator<LocalFsBlobStoreFile> listBlobStoreFiles(File path) throws IOException {
          ArrayList<LocalFsBlobStoreFile> ret = new ArrayList<LocalFsBlobStoreFile>();
          File[] files = path.listFiles();
          if (files != null) {
              for (File sub: files) {
                  try {
                      ret.add(new LocalFsBlobStoreFile(sub.getParentFile(), sub.getName()));
                  } catch (IllegalArgumentException e) {
                      //Ignored the file did not match
                      LOG.warn("Found an unexpected file in {} {}",path, sub.getName());
                  }
              }
          }
          return ret.iterator();
      }
  
      protected Iterator<String> listKeys(File path) throws IOException {
          String[] files = path.list();
          if (files != null) {
              return Arrays.asList(files).iterator();
          }
          return new LinkedList<String>().iterator();
      }
  
      protected void delete(File path) throws IOException {
          Files.deleteIfExists(path.toPath());
      }
  
      public void shutdown() {
          if (cleanup != null) {
              cleanup.cancel();
              cleanup = null;
          }
      }
  }
  