/*
    * 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.hadoop.hbase.regionserver.wal;
  
  import java.io.IOException;
  import java.security.Key;
  import java.security.SecureRandom;
  
  import javax.crypto.spec.SecretKeySpec;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.util.ByteStringer;
  import org.apache.hadoop.hbase.util.EncryptionTest;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.io.crypto.Cipher;
  import org.apache.hadoop.hbase.io.crypto.Encryption;
  import org.apache.hadoop.hbase.io.crypto.Encryptor;
  import org.apache.hadoop.hbase.protobuf.generated.WALProtos.WALHeader;
  import org.apache.hadoop.hbase.security.EncryptionUtil;
  import org.apache.hadoop.hbase.security.User;
  
  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
  public class SecureProtobufLogWriter extends ProtobufLogWriter {
  
    private static final Log LOG = LogFactory.getLog(SecureProtobufLogWriter.class);
    private Encryptor encryptor = null;
  
    @Override
    protected WALHeader buildWALHeader(Configuration conf, WALHeader.Builder builder)
        throws IOException {
      builder.setWriterClsName(SecureProtobufLogWriter.class.getSimpleName());
      if (conf.getBoolean(HConstants.ENABLE_WAL_ENCRYPTION, false)) {
        EncryptionTest.testKeyProvider(conf);
        EncryptionTest.testCipherProvider(conf);
  
        // Get an instance of our cipher
        final String cipherName =
            conf.get(HConstants.CRYPTO_WAL_ALGORITHM_CONF_KEY, HConstants.CIPHER_AES);
        Cipher cipher = Encryption.getCipher(conf, cipherName);
        if (cipher == null) {
          throw new RuntimeException("Cipher '" + cipherName + "' is not available");
        }
  
        // Generate an encryption key for this WAL
        SecureRandom rng = new SecureRandom();
        byte[] keyBytes = new byte[cipher.getKeyLength()];
        rng.nextBytes(keyBytes);
        Key key = new SecretKeySpec(keyBytes, cipher.getName());
        builder.setEncryptionKey(ByteStringer.wrap(EncryptionUtil.wrapKey(conf,
            conf.get(HConstants.CRYPTO_WAL_KEY_NAME_CONF_KEY,
                conf.get(HConstants.CRYPTO_MASTERKEY_NAME_CONF_KEY,
                    User.getCurrent().getShortName())),
            key)));
  
        // Set up the encryptor
        encryptor = cipher.getEncryptor();
        encryptor.setKey(key);
  
        if (LOG.isTraceEnabled()) {
          LOG.trace("Initialized secure protobuf WAL: cipher=" + cipher.getName());
        }
      }
      builder.setCellCodecClsName(SecureWALCellCodec.class.getName());
      return super.buildWALHeader(conf, builder);
    }
  
    @Override
    protected void initAfterHeader(boolean doCompress) throws IOException {
      if (conf.getBoolean(HConstants.ENABLE_WAL_ENCRYPTION, false) && encryptor != null) {
        WALCellCodec codec = SecureWALCellCodec.getCodec(this.conf, encryptor);
        this.cellEncoder = codec.getEncoder(this.output);
        // We do not support compression
        this.compressionContext = null;
      } else {
        super.initAfterHeader(doCompress);
      }
    }
  
  }