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.cassandra.service;
  
  import java.net.InetAddress;
  import java.util.concurrent.TimeUnit;
  import java.util.function.Predicate;
  
  import com.google.common.annotations.VisibleForTesting;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import io.netty.channel.EventLoopGroup;
  import io.netty.channel.epoll.Epoll;
  import io.netty.channel.epoll.EpollEventLoopGroup;
  import io.netty.channel.nio.NioEventLoopGroup;
  import io.netty.util.Version;
  import org.apache.cassandra.auth.AuthenticatedUser;
  import org.apache.cassandra.config.DatabaseDescriptor;
  import org.apache.cassandra.config.EncryptionOptions;
  import org.apache.cassandra.metrics.ClientMetrics;
  import org.apache.cassandra.transport.Dispatcher;
  import org.apache.cassandra.transport.Server;
  import org.apache.cassandra.utils.NativeLibrary;
  
  import static org.apache.cassandra.config.CassandraRelevantProperties.NATIVE_EPOLL_ENABLED;
  
  /**
   * Handles native transport server lifecycle and associated resources. Lazily initialized.
   */
  public class NativeTransportService
  {
  
      private static final Logger logger = LoggerFactory.getLogger(NativeTransportService.class);
  
      private Server server = null;
  
      private boolean initialized = false;
      private EventLoopGroup workerGroup;
  
      /**
       * Creates netty thread pools and event loops.
       */
      @VisibleForTesting
      synchronized void initialize()
      {
          if (initialized)
              return;
  
          if (useEpoll())
          {
              workerGroup = new EpollEventLoopGroup();
              logger.info("Netty using native Epoll event loop");
          }
          else
          {
              workerGroup = new NioEventLoopGroup();
              logger.info("Netty using Java NIO event loop");
          }
  
          int nativePort = DatabaseDescriptor.getNativeTransportPort();
          InetAddress nativeAddr = DatabaseDescriptor.getRpcAddress();
  
          org.apache.cassandra.transport.Server.Builder builder = new org.apache.cassandra.transport.Server.Builder()
                                                                  .withEventLoopGroup(workerGroup)
                                                                  .withHost(nativeAddr);
  
          EncryptionOptions.TlsEncryptionPolicy encryptionPolicy = DatabaseDescriptor.getNativeProtocolEncryptionOptions().tlsEncryptionPolicy();
          server = builder.withTlsEncryptionPolicy(encryptionPolicy).withPort(nativePort).build();
  
          ClientMetrics.instance.init(server);
  
          initialized = true;
      }
  
      /**
       * Starts native transport server.
       */
      public void start()
      {
          logger.info("Using Netty Version: {}", Version.identify().entrySet());
          initialize();
          server.start();
      }
  
      /**
       * Stops currently running native transport server.
       */
      public void stop()
      {
          stop(false);
      }
  
      public void stop(boolean force)
      {
          if (server != null)
              server.stop(force);
      }
  
      /**
       * Ultimately stops servers and closes all resources.
       */
      public void destroy()
      {
          stop();
          ClientMetrics.instance.release();
          server = null;
  
          // shutdown executors used by netty for native transport server
          if (workerGroup != null)
              workerGroup.shutdownGracefully(3, 5, TimeUnit.SECONDS).awaitUninterruptibly();
  
          Dispatcher.shutdown();
      }
  
      /**
       * @return intend to use epoll based event looping
       */
      public static boolean useEpoll()
      {
          final boolean enableEpoll = NATIVE_EPOLL_ENABLED.getBoolean();
  
          if (enableEpoll && !Epoll.isAvailable() && NativeLibrary.osType == NativeLibrary.OSType.LINUX)
              logger.warn("epoll not available", Epoll.unavailabilityCause());
  
          return enableEpoll && Epoll.isAvailable();
      }
  
      /**
       * @return true in case native transport server is running
       */
      public boolean isRunning()
      {
          return server != null && server.isRunning();
      }
  
      @VisibleForTesting
      EventLoopGroup getWorkerGroup()
      {
          return workerGroup;
      }
  
      @VisibleForTesting
      Server getServer()
      {
          return server;
      }
  
      public void clearConnectionHistory()
      {
          server.clearConnectionHistory();
      }
  
      public void disconnect(Predicate<AuthenticatedUser> userPredicate)
      {
          server.disconnect(userPredicate);
      }
  }
  