code: /*
   * Copyright 2019 Mitsunori Komatsu (komamitsu)
   *
   * Licensed 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.komamitsu.fluency.fluentd.ingester.sender;
  
  import com.fasterxml.jackson.databind.ObjectMapper;
  import org.komamitsu.fluency.fluentd.ingester.Response;
  import org.komamitsu.fluency.fluentd.ingester.sender.failuredetect.FailureDetector;
  import org.komamitsu.fluency.util.ExecutorServiceUtils;
  import org.komamitsu.fluency.validation.Validatable;
  import org.komamitsu.fluency.validation.annotation.Min;
  import org.msgpack.jackson.dataformat.MessagePackFactory;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.net.SocketTimeoutException;
  import java.nio.ByteBuffer;
  import java.util.List;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Future;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  
  public abstract class NetworkSender<T>
          extends FluentdSender
  {
      private static final Logger LOG = LoggerFactory.getLogger(NetworkSender.class);
      private final byte[] optionBuffer = new byte[256];
      private final ExecutorService executorService = ExecutorServiceUtils.newSingleThreadDaemonExecutor();
  
      private final Config config;
      private final FailureDetector failureDetector;
      private final ObjectMapper objectMapper = new ObjectMapper(new MessagePackFactory());
  
      NetworkSender(FailureDetector failureDetector)
      {
          this(new Config(), failureDetector);
      }
  
      NetworkSender(Config config, FailureDetector failureDetector)
      {
          super(config);
          this.config = config;
          this.failureDetector = failureDetector;
      }
  
      @Override
      public boolean isAvailable()
      {
          return failureDetector == null || failureDetector.isAvailable();
      }
  
      abstract T getOrCreateSocketInternal()
              throws IOException;
  
      private synchronized T getOrCreateSocket()
              throws IOException
      {
          return getOrCreateSocketInternal();
      }
  
      abstract void sendBuffers(T socket, List<ByteBuffer> buffers)
              throws IOException;
  
      abstract void recvResponse(T socket, ByteBuffer buffer)
              throws IOException;
  
      private void propagateFailure(Throwable e)
      {
          if (failureDetector != null) {
              failureDetector.onFailure(e);
          }
      }
  
      @Override
      protected synchronized void sendInternal(List<ByteBuffer> buffers, String ackToken)
              throws IOException
      {
          long totalDataSize = buffers.stream().mapToInt(ByteBuffer::remaining).sum();
  
          try {
              LOG.trace("send(): sender={}, totalDataSize={}", this, totalDataSize);
              final T socket = getOrCreateSocket();
              sendBuffers(socket, buffers);
  
              if (ackToken == null) {
                  return;
              }
  
              // For ACK response mode
              final ByteBuffer byteBuffer = ByteBuffer.wrap(optionBuffer);
  
              Future<Void> future = executorService.submit(() -> {
                  LOG.trace("recv(): sender={}", this);
                  recvResponse(socket, byteBuffer);
                  return null;
              });
  
              try {
                  future.get(config.getReadTimeoutMilli(), TimeUnit.MILLISECONDS);
              }
              catch (InterruptedException e) {
                  throw new IOException("InterruptedException occurred", e);
              }
              catch (ExecutionException e) {
                  throw new IOException("ExecutionException occurred", e);
              }
              catch (TimeoutException e) {
                  throw new SocketTimeoutException("Socket read timeout");
              }
  
              Response response = objectMapper.readValue(optionBuffer, Response.class);
              if (!ackToken.equals(response.getAck())) {
                  throw new UnmatchedAckException("Ack tokens don't matched: expected=" + ", got=" + response.getAck());
              }
          }
          catch (IOException e) {
              LOG.error("Failed to send {} bytes data", totalDataSize);
              closeSocket();
              propagateFailure(e);
              throw e;
          }
      }
  
      abstract void closeSocket()
              throws IOException;
  
      @Override
      public synchronized void close()
              throws IOException
      {
          try {
              // Wait to confirm unsent request is flushed
              try {
                  TimeUnit.MILLISECONDS.sleep(config.getWaitBeforeCloseMilli());
              }
              catch (InterruptedException e) {
                  LOG.warn("Interrupted", e);
                  Thread.currentThread().interrupt();
              }
  
              closeSocket();
          }
          finally {
              try {
                  if (failureDetector != null) {
                      failureDetector.close();
                  }
              }
              finally {
                  ExecutorServiceUtils.finishExecutorService(executorService);
              }
          }
      }
  
      public int getConnectionTimeoutMilli()
      {
          return config.getConnectionTimeoutMilli();
      }
  
      public int getReadTimeoutMilli()
      {
          return config.getReadTimeoutMilli();
      }
  
      public FailureDetector getFailureDetector()
      {
          return failureDetector;
      }
  
      @Override
      public String toString()
      {
          return "NetworkSender{" +
                  "config=" + config +
                  ", failureDetector=" + failureDetector +
                  "} " + super.toString();
      }
  
      public static class UnmatchedAckException
              extends IOException
      {
          public UnmatchedAckException(String message)
          {
              super(message);
          }
      }
  
      public static class Config
              extends FluentdSender.Config
      {
          @Min(10)
          private int connectionTimeoutMilli = 5000;
          @Min(10)
          private int readTimeoutMilli = 5000;
          @Min(0)
          private int waitBeforeCloseMilli = 1000;
  
          public int getConnectionTimeoutMilli()
          {
              return connectionTimeoutMilli;
          }
  
          public void setConnectionTimeoutMilli(int connectionTimeoutMilli)
          {
              this.connectionTimeoutMilli = connectionTimeoutMilli;
          }
  
          public int getReadTimeoutMilli()
          {
              return readTimeoutMilli;
          }
  
          public void setReadTimeoutMilli(int readTimeoutMilli)
          {
              this.readTimeoutMilli = readTimeoutMilli;
          }
  
          public int getWaitBeforeCloseMilli()
          {
              return waitBeforeCloseMilli;
          }
  
          public void setWaitBeforeCloseMilli(int waitBeforeCloseMilli)
          {
              this.waitBeforeCloseMilli = waitBeforeCloseMilli;
          }
  
          @Override
          public String toString()
          {
              return "Config{" +
                      "connectionTimeoutMilli=" + connectionTimeoutMilli +
                      ", readTimeoutMilli=" + readTimeoutMilli +
                      ", waitBeforeCloseMilli=" + waitBeforeCloseMilli +
                      "} " + super.toString();
          }
      }
  }
  