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
   *
   *     https://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.avro.ipc.netty;
  
  import java.io.IOException;
  import java.net.InetSocketAddress;
  import java.nio.ByteBuffer;
  import java.util.List;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.function.Consumer;
  
  import org.apache.avro.ipc.Responder;
  import org.apache.avro.ipc.Server;
  import org.apache.avro.ipc.netty.NettyTransportCodec.NettyDataPack;
  import org.apache.avro.ipc.netty.NettyTransportCodec.NettyFrameDecoder;
  import org.apache.avro.ipc.netty.NettyTransportCodec.NettyFrameEncoder;
  import io.netty.bootstrap.ServerBootstrap;
  import io.netty.channel.Channel;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInitializer;
  import io.netty.channel.ChannelOption;
  import io.netty.channel.DefaultEventLoopGroup;
  import io.netty.channel.EventLoopGroup;
  import io.netty.channel.SimpleChannelInboundHandler;
  import io.netty.channel.nio.NioEventLoopGroup;
  import io.netty.channel.socket.SocketChannel;
  import io.netty.channel.socket.nio.NioServerSocketChannel;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A Netty-based RPC {@link Server} implementation.
   */
  public class NettyServer implements Server {
    private static final Logger LOG = LoggerFactory.getLogger(NettyServer.class.getName());
  
    private final Responder responder;
  
    private final Channel serverChannel;
    private final EventLoopGroup bossGroup;
    private final EventLoopGroup workerGroup;
    private final EventLoopGroup callerGroup;
    private final CountDownLatch closed = new CountDownLatch(1);
    private final AtomicInteger activeCount = new AtomicInteger(0);
  
    public NettyServer(Responder responder, InetSocketAddress addr) throws InterruptedException {
      this(responder, addr, null);
    }
  
    public NettyServer(Responder responder, InetSocketAddress addr, final Consumer<SocketChannel> initializer)
        throws InterruptedException {
      this(responder, addr, initializer, null, null, null, null);
    }
  
    public NettyServer(Responder responder, InetSocketAddress addr, final Consumer<SocketChannel> initializer,
        final Consumer<ServerBootstrap> bootStrapInitialzier) throws InterruptedException {
      this(responder, addr, initializer, bootStrapInitialzier, null, null, null);
    }
  
    public NettyServer(Responder responder, InetSocketAddress addr, final Consumer<SocketChannel> initializer,
        final Consumer<ServerBootstrap> bootStrapInitialzier, EventLoopGroup bossGroup, EventLoopGroup workerGroup,
        EventLoopGroup callerGroup) throws InterruptedException {
      this.bossGroup = bossGroup == null ? new NioEventLoopGroup(1) : bossGroup;
      this.workerGroup = workerGroup == null ? new NioEventLoopGroup(10) : workerGroup;
      this.callerGroup = callerGroup == null ? new DefaultEventLoopGroup(16) : callerGroup;
      this.responder = responder;
      ServerBootstrap bootstrap = new ServerBootstrap().group(this.bossGroup, this.workerGroup)
          .channel(NioServerSocketChannel.class).childHandler(new ChannelInitializer<SocketChannel>() {
            @Override
            public void initChannel(SocketChannel ch) throws Exception {
              if (initializer != null) {
                initializer.accept(ch);
              }
              ch.pipeline().addLast("frameDecoder", new NettyFrameDecoder())
                  .addLast("frameEncoder", new NettyFrameEncoder()).addLast("handler", new NettyServerAvroHandler());
            }
          }).option(ChannelOption.SO_BACKLOG, 1024).childOption(ChannelOption.TCP_NODELAY, true)
          .childOption(ChannelOption.SO_KEEPALIVE, true);
  
      if (bootStrapInitialzier != null) {
        bootStrapInitialzier.accept(bootstrap);
      }
      serverChannel = bootstrap.bind(addr).sync().channel();
    }
  
    @Override
    public void start() {
      // No-op.
    }
  
    @Override
    public void close() {
      workerGroup.shutdownGracefully().syncUninterruptibly();
      bossGroup.shutdownGracefully().syncUninterruptibly();
      try {
        serverChannel.closeFuture().sync();
      } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      closed.countDown();
    }
  
    @Override
    public int getPort() {
      return ((InetSocketAddress) serverChannel.localAddress()).getPort();
    }
  
    @Override
    public void join() throws InterruptedException {
      closed.await();
    }
  
    /**
     *
     * @return The number of clients currently connected to this server.
     */
    public int getNumActiveConnections() {
      return activeCount.get();
    }
  
    /**
     * Avro server handler for the Netty transport
     */
    class NettyServerAvroHandler extends SimpleChannelInboundHandler<NettyDataPack> {
  
      private NettyTransceiver connectionMetadata = new NettyTransceiver();
  
      @Override
      public void channelActive(ChannelHandlerContext ctx) throws Exception {
        activeCount.incrementAndGet();
        super.channelActive(ctx);
      }
  
      @Override
      protected void channelRead0(ChannelHandlerContext ctx, final NettyDataPack dataPack) throws Exception {
        callerGroup.submit(new Runnable() {
          @Override
          public void run() {
            List<ByteBuffer> req = dataPack.getDatas();
            try {
              List<ByteBuffer> res = responder.respond(req, connectionMetadata);
              // response will be null for oneway messages.
              if (res != null) {
                dataPack.setDatas(res);
                ctx.channel().writeAndFlush(dataPack);
              }
            } catch (IOException e) {
              LOG.warn("unexpected error");
            }
          }
        });
      }
  
      @Override
      public void exceptionCaught(ChannelHandlerContext ctx, Throwable e) {
        LOG.warn("Unexpected exception from downstream.", e);
        ctx.close().syncUninterruptibly();
      }
  
      @Override
      public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        LOG.info("Connection to {} disconnected.", ctx.channel().remoteAddress());
        activeCount.decrementAndGet();
        super.channelInactive(ctx);
      }
  
    }
  }
  