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.asterix.replication.messaging;
  
  import java.io.ByteArrayInputStream;
  import java.io.DataInputStream;
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.net.InetSocketAddress;
  import java.nio.ByteBuffer;
  import java.nio.channels.SocketChannel;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.stream.Stream;
  
  import org.apache.asterix.common.api.INcApplicationContext;
  import org.apache.asterix.common.exceptions.ReplicationException;
  import org.apache.asterix.replication.api.IReplicationMessage;
  import org.apache.asterix.replication.api.PartitionReplica;
  import org.apache.asterix.replication.management.NetworkingUtil;
  import org.apache.hyracks.api.network.ISocketChannel;
  import org.apache.hyracks.api.network.ISocketChannelFactory;
  import org.apache.hyracks.data.std.util.ExtendedByteArrayOutputStream;
  import org.apache.hyracks.util.NetworkUtil;
  import org.apache.hyracks.util.StorageUtil;
  
  public class ReplicationProtocol {
  
      /**
       * All replication messages start with ReplicationRequestType (4 bytes), then the length of the request in bytes
       */
      public static final String LOG_REPLICATION_ACK = "$";
      public static final int INITIAL_BUFFER_SIZE = StorageUtil.getIntSizeInBytes(4, StorageUtil.StorageUnit.KILOBYTE);
      private static final int REPLICATION_REQUEST_TYPE_SIZE = Integer.BYTES;
      private static final int REPLICATION_REQUEST_HEADER_SIZE = REPLICATION_REQUEST_TYPE_SIZE + Integer.BYTES;
  
      public enum ReplicationRequestType {
          GOODBYE,
          ACK,
          PARTITION_RESOURCES_REQUEST,
          PARTITION_RESOURCES_RESPONSE,
          REPLICATE_RESOURCE_FILE,
          DELETE_RESOURCE_FILE,
          CHECKPOINT_PARTITION,
          LSM_COMPONENT_MASK,
          MARK_COMPONENT_VALID,
          DROP_INDEX,
          REPLICATE_LOGS,
          DELETE_PARTITION
      }
  
      private static final Map<Integer, ReplicationRequestType> TYPES = new HashMap<>();
  
      static {
          Stream.of(ReplicationRequestType.values()).forEach(type -> TYPES.put(type.ordinal(), type));
      }
  
      public static ByteBuffer readRequest(ISocketChannel socketChannel, ByteBuffer dataBuffer) throws IOException {
          // read request size
          NetworkingUtil.readBytes(socketChannel, dataBuffer, Integer.BYTES);
          final int requestSize = dataBuffer.getInt();
          final ByteBuffer buf = ensureSize(dataBuffer, requestSize);
          // read request
          NetworkingUtil.readBytes(socketChannel, buf, requestSize);
          return buf;
      }
  
      public static ReplicationRequestType getRequestType(ISocketChannel socketChannel, ByteBuffer byteBuffer)
              throws IOException {
          // read replication request type
          NetworkingUtil.readBytes(socketChannel, byteBuffer, REPLICATION_REQUEST_TYPE_SIZE);
          return TYPES.get(byteBuffer.getInt());
      }
  
      private static ByteBuffer getGoodbyeBuffer() {
          ByteBuffer bb = ByteBuffer.allocate(REPLICATION_REQUEST_TYPE_SIZE);
          bb.putInt(ReplicationRequestType.GOODBYE.ordinal());
          bb.flip();
          return bb;
      }
  
      public static int getTxnIdFromLogAckMessage(String msg) {
          return Integer.parseInt(msg.substring(msg.indexOf(LOG_REPLICATION_ACK) + 1));
      }
  
      public static void sendGoodbye(ISocketChannel socketChannel) throws IOException {
          ByteBuffer goodbyeBuffer = ReplicationProtocol.getGoodbyeBuffer();
          NetworkingUtil.transferBufferToChannel(socketChannel, goodbyeBuffer);
      }
  
      public static void sendAck(ISocketChannel socketChannel, ByteBuffer buf) {
          try {
              buf.clear();
              buf.putInt(ReplicationRequestType.ACK.ordinal());
              buf.flip();
              NetworkingUtil.transferBufferToChannel(socketChannel, buf);
          } catch (IOException e) {
              throw new ReplicationException(e);
          }
      }
  
      public static void waitForAck(PartitionReplica replica) throws IOException {
          final ISocketChannel channel = replica.getChannel();
          final ByteBuffer buf = replica.getReusableBuffer();
          ReplicationRequestType responseFunction = ReplicationProtocol.getRequestType(channel, buf);
          if (responseFunction != ReplicationRequestType.ACK) {
              throw new IllegalStateException("Unexpected response while waiting for ack.");
          }
      }
  
      public static void sendTo(PartitionReplica replica, IReplicationMessage task) {
          final ISocketChannel channel = replica.getChannel();
          final ByteBuffer buf = replica.getReusableBuffer();
          sendTo(channel, task, buf);
      }
  
      public static void sendTo(ISocketChannel channel, IReplicationMessage task, ByteBuffer buf) {
          ExtendedByteArrayOutputStream outputStream = new ExtendedByteArrayOutputStream();
          try (DataOutputStream oos = new DataOutputStream(outputStream)) {
              task.serialize(oos);
              final int requestSize = REPLICATION_REQUEST_HEADER_SIZE + oos.size();
              final ByteBuffer requestBuffer = ensureSize(buf, requestSize);
              requestBuffer.putInt(task.getMessageType().ordinal());
              requestBuffer.putInt(oos.size());
              requestBuffer.put(outputStream.getByteArray(), 0, outputStream.getLength());
              requestBuffer.flip();
              NetworkingUtil.transferBufferToChannel(channel, requestBuffer);
              channel.getSocketChannel().socket().getOutputStream().flush();
          } catch (IOException e) {
              throw new ReplicationException(e);
          }
      }
  
      public static IReplicationMessage read(ISocketChannel socketChannel, ByteBuffer buffer) throws IOException {
          final ReplicationRequestType type = getRequestType(socketChannel, buffer);
          return readMessage(type, socketChannel, buffer);
      }
  
      public static IReplicationMessage readMessage(ReplicationRequestType type, ISocketChannel socketChannel,
              ByteBuffer buffer) {
          try {
              final ByteBuffer requestBuf = ReplicationProtocol.readRequest(socketChannel, buffer);
              final ByteArrayInputStream input =
                      new ByteArrayInputStream(requestBuf.array(), requestBuf.position(), requestBuf.limit());
              try (DataInputStream dis = new DataInputStream(input)) {
                  switch (type) {
                      case PARTITION_RESOURCES_REQUEST:
                          return PartitionResourcesListTask.create(dis);
                      case PARTITION_RESOURCES_RESPONSE:
                          return PartitionResourcesListResponse.create(dis);
                      case REPLICATE_RESOURCE_FILE:
                          return ReplicateFileTask.create(dis);
                      case DELETE_RESOURCE_FILE:
                          return DeleteFileTask.create(dis);
                      case CHECKPOINT_PARTITION:
                          return CheckpointPartitionIndexesTask.create(dis);
                      case LSM_COMPONENT_MASK:
                          return ComponentMaskTask.create(dis);
                      case DROP_INDEX:
                          return DropIndexTask.create(dis);
                      case MARK_COMPONENT_VALID:
                          return MarkComponentValidTask.create(dis);
                      case REPLICATE_LOGS:
                          return ReplicateLogsTask.create(dis);
                      case DELETE_PARTITION:
                          return DeletePartitionTask.create(dis);
                      default:
                          throw new IllegalStateException("Unrecognized replication message");
                  }
              }
          } catch (IOException e) {
              throw new ReplicationException(e);
          }
      }
  
      public static ByteBuffer getEndLogReplicationBuffer() {
          final int logsBatchSize = 1;
          final ByteBuffer endLogRepBuffer =
                  ByteBuffer.allocate(Integer.BYTES + ReplicateLogsTask.END_REPLICATION_LOG_SIZE);
          endLogRepBuffer.putInt(logsBatchSize);
          endLogRepBuffer.put((byte) 0);
          endLogRepBuffer.flip();
          return endLogRepBuffer;
      }
  
      public static ISocketChannel establishReplicaConnection(INcApplicationContext appCtx, InetSocketAddress location)
              throws IOException {
          final SocketChannel socketChannel = SocketChannel.open();
          NetworkUtil.configure(socketChannel);
          socketChannel.connect(location);
          // perform handshake in a non-blocking mode
          socketChannel.configureBlocking(false);
          final ISocketChannelFactory socketChannelFactory =
                  appCtx.getServiceContext().getControllerService().getNetworkSecurityManager().getSocketChannelFactory();
          final ISocketChannel clientChannel = socketChannelFactory.createClientChannel(socketChannel);
          if (clientChannel.requiresHandshake() && !clientChannel.handshake()) {
              throw new IllegalStateException("handshake failure");
          }
          // switch to blocking mode after handshake success
          socketChannel.configureBlocking(true);
          return clientChannel;
      }
  
      private static ByteBuffer ensureSize(ByteBuffer buffer, int size) {
          if (buffer == null || buffer.capacity() < size) {
              return ByteBuffer.allocate(size);
          }
          buffer.clear();
          return buffer;
      }
  }
  