How to use

RocksDbKeyValueReader

in

org.apache.samza.storage.kv

 public static void main(String[] args) throws RocksDBException {
  RocksDbReadingTool tool = new RocksDbReadingTool();
  OptionSet options = tool.parser().parse(args);
  MapConfig config = tool.loadConfig(options);
  String path = tool.getDbPath();
  String dbName = tool.getDbName();
  RocksDbKeyValueReader kvReader = new RocksDbKeyValueReader(dbName, path, config);

  for (Object obj : tool.getKeys()) {
   Object result = kvReader.get(obj);
   tool.outputResult(obj, result);
  }

  kvReader.stop();
 }
}

/**
 * Construct the <code>RocksDbKeyValueReader</code> with store's name,
 * database's path and Samza's config
 *
 * @param storeName name of the RocksDb defined in the config file
 * @param dbPath path to the db directory
 * @param config Samza's config
 */
public RocksDbKeyValueReader(String storeName, String dbPath, Config config) {
 // get the key serde and value serde from the config
 JavaStorageConfig storageConfig = new JavaStorageConfig(config);
 JavaSerializerConfig serializerConfig = new JavaSerializerConfig(config);
 keySerde = getSerdeFromName(storageConfig.getStorageKeySerde(storeName), serializerConfig);
 valueSerde = getSerdeFromName(storageConfig.getStorageMsgSerde(storeName), serializerConfig);
 // get db options
 Options options = RocksDbOptionsHelper.options(config, 1, new File(dbPath), StorageEngineFactory.StoreMode.ReadWrite);
 // open the db
 RocksDB.loadLibrary();
 try {
  db = RocksDB.openReadOnly(options, dbPath);
 } catch (RocksDBException e) {
  throw new SamzaException("can not open the rocksDb in " + dbPath, e);
 }
}

/**
 * Construct the <code>RocksDbKeyValueReader</code> with store's name,
 * database's path and Samza's config
 *
 * @param storeName name of the RocksDb defined in the config file
 * @param dbPath path to the db directory
 * @param config Samza's config
 */
public RocksDbKeyValueReader(String storeName, String dbPath, Config config) {
 // get the key serde and value serde from the config
 JavaStorageConfig storageConfig = new JavaStorageConfig(config);
 JavaSerializerConfig serializerConfig = new JavaSerializerConfig(config);
 keySerde = getSerdeFromName(storageConfig.getStorageKeySerde(storeName), serializerConfig);
 valueSerde = getSerdeFromName(storageConfig.getStorageMsgSerde(storeName), serializerConfig);
 // get db options
 Options options = RocksDbOptionsHelper.options(config, 1);
 // open the db
 RocksDB.loadLibrary();
 try {
  db = RocksDB.openReadOnly(options, dbPath);
 } catch (RocksDBException e) {
  throw new SamzaException("can not open the rocksDb in " + dbPath, e);
 }
}

 public static void main(String[] args) throws RocksDBException {
  RocksDbReadingTool tool = new RocksDbReadingTool();
  OptionSet options = tool.parser().parse(args);
  MapConfig config = tool.loadConfig(options);
  String path = tool.getDbPath();
  String dbName = tool.getDbName();
  RocksDbKeyValueReader kvReader = new RocksDbKeyValueReader(dbName, path, config);

  for (Object obj : tool.getKeys()) {
   Object result = kvReader.get(obj);
   tool.outputResult(obj, result);
  }

  kvReader.stop();
 }
}

/**
 * Construct the <code>RocksDbKeyValueReader</code> with store's name,
 * database's path and Samza's config
 *
 * @param storeName name of the RocksDb defined in the config file
 * @param dbPath path to the db directory
 * @param config Samza's config
 */
public RocksDbKeyValueReader(String storeName, String dbPath, Config config) {
 // get the key serde and value serde from the config
 JavaStorageConfig storageConfig = new JavaStorageConfig(config);
 JavaSerializerConfig serializerConfig = new JavaSerializerConfig(config);
 keySerde = getSerdeFromName(storageConfig.getStorageKeySerde(storeName), serializerConfig);
 valueSerde = getSerdeFromName(storageConfig.getStorageMsgSerde(storeName), serializerConfig);
 // get db options
 Options options = RocksDbOptionsHelper.options(config, 1);
 // open the db
 RocksDB.loadLibrary();
 try {
  db = RocksDB.openReadOnly(options, dbPath);
 } catch (RocksDBException e) {
  throw new SamzaException("can not open the rocksDb in " + dbPath, e);
 }
}

 public static void main(String[] args) throws RocksDBException {
  RocksDbReadingTool tool = new RocksDbReadingTool();
  OptionSet options = tool.parser().parse(args);
  MapConfig config = tool.loadConfig(options);
  String path = tool.getDbPath();
  String dbName = tool.getDbName();
  RocksDbKeyValueReader kvReader = new RocksDbKeyValueReader(dbName, path, config);

  for (Object obj : tool.getKeys()) {
   Object result = kvReader.get(obj);
   tool.outputResult(obj, result);
  }

  kvReader.stop();
 }
}

@Test
public void testReadCorrectDbValue() throws RocksDBException {
 HashMap<String, String> map = new HashMap<String, String>();
 map.put("stores." + DB_NAME + ".factory", "mockFactory");
 map.put("stores." + DB_NAME + ".key.serde", "string");
 map.put("stores." + DB_NAME + ".msg.serde", "string");
 Config config = new MapConfig(map);
 RocksDbKeyValueReader reader = new RocksDbKeyValueReader(DB_NAME, dirPath.toString(), config);
 assertEquals("this is string", reader.get("testString"));
 // should throw exception if the input is in other type
 boolean throwClassCastException = false;
 try {
  reader.get(123);
 } catch (Exception e) {
  if (e instanceof ClassCastException) {
   throwClassCastException = true;
  }
 }
 assertTrue(throwClassCastException);
 reader.stop();
 // test with customized serde
 map.put("serializers.registry.mock.class", IntegerSerdeFactory.class.getCanonicalName());
 map.put("stores." + DB_NAME + ".key.serde", "mock");
 map.put("stores." + DB_NAME + ".msg.serde", "mock");
 config = new MapConfig(map);
 reader = new RocksDbKeyValueReader(DB_NAME, dirPath.toString(), config);
 assertEquals(456, reader.get(123));
 assertNull(reader.get(789));
 reader.stop();
}